_UNIVERSITY OF CALIFORNIA PUBLICATIONS_

                         COLLEGE OF AGRICULTURE
                     AGRICULTURAL EXPERIMENT STATION
                          BERKELEY, CALIFORNIA

                        THE ALMOND IN CALIFORNIA

                                   BY
                              R. H. TAYLOR

                            BULLETIN No. 297
                              AUGUST, 1918

                     UNIVERSITY OF CALIFORNIA PRESS
                                BERKELEY
                                  1918


    BENJAMIN IDE WHEELER, President of the University.


EXPERIMENT STATION STAFF


HEADS OF DIVISIONS

    THOMAS FORSYTH HUNT, Director.
    EDWARD J. WICKSON, Horticulture (Emeritus).
    HERBERT J. WEBBER, Director Citrus Experiment Station; Plant Breeding.
    HUBERT E. VAN NORMAN, Vice-Director; Dairy Management.
    WILLIAM A. SETCHELL, Botany.
    MYER E. JAFFA, Nutrition.
    CHARLES W. WOODWORTH, Entomology.
    RALPH E. SMITH, Plant Pathology.
    J. ELIOT COIT, Citriculture.
    JOHN W. GILMORE, Agronomy.
    CHARLES F. SHAW, Soil Technology.
    JOHN W. GREGG, Landscape Gardening and Floriculture.
    FREDERIC T. BIOLETTI, Viticulture and Enology.
    WARREN T. CLARKE, Agricultural Extension.
    JOHN S. BURD, Agricultural Chemistry.
    CHARLES B. LIPMAN, Soil Chemistry and Bacteriology.
    ‡CLARENCE M. HARING, Veterinary Science and Bacteriology.
    ERNEST B. BABCOCK, Genetics.
    GORDON H. TRUE, Animal Husbandry.
    JAMES T. BARRETT, Plant Pathology.
    FRITZ W. WOLL, Animal Nutrition.
    WALTER MULFORD, Forestry.
    W. P. KELLEY, Agricultural Chemistry.
    H. J. QUAYLE, Entomology.
    J. B. DAVIDSON, Agricultural Engineering.
    ELWOOD MEAD, Rural Institutions.
    H. S. REED, Plant Physiology.
    W. L. HOWARD, Pomology.
    †FRANK ADAMS, Irrigation Investigations.
    C. L. ROADHOUSE, Dairy Industry.
    O. J. KERN, Agricultural Education.
    JOHN E. DOUGHERTY, Poultry Husbandry.
    S. S. ROGERS, Olericulture.
    J. G. MOODEY, Assistant to the Director.
    Mrs. D. L. BUNNELL, Librarian.


DIVISION OF POMOLOGY

    W. L. HOWARD
    R. H. TAYLOR
    A. H. HENDRICKSON
    *E. L. OVERHOLSER
    W. P. TUFTS
    W. L. SWEET
    G. L. PHILP
    ‡V. W. HOFFMAN
    M. N. WOOD

‡ In military service.

† In co-operation with office of Public Roads and Rural Engineering, U.
S. Department of Agriculture.

* Exchange professor from Cornell University for 1918-19.




THE ALMOND IN CALIFORNIA

BY R. H. TAYLOR




INTRODUCTION


The almond (_Prunus communis_) is supposed to be native to the countries
around the Mediterranean and at present the bulk of the world’s supply
is produced in that region. It resembles the peach somewhat in manner of
growth and character of blossoms and leaves, but the wood is much harder
and the tree is longer-lived under equally favorable conditions. The
fruit, instead of having a thick, fleshy pericarp as in the case of the
peach, has a thin, leathery pericarp or hull, which splits on ripening
and generally opens when dry, exposing the nut inside.

California produces over 98 per cent of the entire American crop and has
done so for many years. During the period from 1900 to 1913 the number
of bearing trees remained approximately the same, new plantings having
replaced old orchards that were being pulled out. The variation in
California production from year to year prior to 1915, as shown in figure
1, is due to seasonal variations rather than to change in acreage.

Imports into the United States from the Mediterranean countries are also
shown in figure 1, the top line representing the total imports, the other
lines, as indicated, showing the proportion of that total originating in
the three principal countries exporting to the United States. Previous to
1912 the records of shelled and unshelled almonds were not kept separate.
Since the records have been segregated, the percentages of shelled
almonds imported each year have been approximately as follows:

                Per cent
    1912-13        83
    1913-14        70
    1914-15        71
    1915-16        82
    1916-17        79
                  ---
        Average    77

With the 1915 crop the production in California entered upon what appears
to be a long prospective increase. The large acreage of almonds set out
in the last four or five years is the result of greatly improved market
conditions due to the successful work of the California Almond Growers’
Exchange. The first of these new plantings are now coming into bearing,
and each year for many years in the future will continue to see increased
yields. Large acreages are still being planted so that the almond
production in California bids fair to continue to grow.

Within the next few years California growers will, in all probability,
be forced to accept lower prices for their almonds than they are now
receiving. The American markets are fully supplied at present prices,
yet constantly increasing acreage will inevitably result in a greatly
increased tonnage. European almonds are being produced at a lower net
cost and can be laid down on the Atlantic Coast more cheaply than is
possible with the California product. This brings the grower face to face
with the necessity of becoming more thoroughly familiar with the most
economical methods of production and marketing if they are to continue
to make a profit. It is essential, therefore, that a careful study be
made of all the factors concerned in the growth, production and final
disposition of the almond crop.


HABITS

The almond is the first of the deciduous fruit trees to start growth
and come into bloom in the spring, and normally the last one to shed
its leaves in the fall. In other words, it has a very short period of
rest. When the trees are forced into premature dormancy by mites or
lack of moisture, they soon reach the end of their normal rest period
before the winter season is over. Then the first warm weather in spring
will bring the trees into blossom. In some cases where moisture and
temperature conditions are favorable late in the fall, they may actually
blossom before the winter season. In young trees that have become dormant
unusually early, the rest period may terminate and then the tips of the
branches resume growth and continue to slowly develop new leaves at the
terminals throughout the winter. Trees which have been kept growing
thriftily until the leaves have been forced to fall by the cold weather
and frosts of winter, do not tend to blossom as early in the spring, nor
do they open under the influence of a few days of warm weather in late
winter or early spring.

Young trees blossom somewhat later than the older trees, and buds on
sucker growth blossom later than the more mature portions of the same
tree. The difference may amount to three or four days or almost a week.
Well-grown trees carry large numbers of blossoms over the entire tree, as
shown in figure 2.

[Illustration: Fig. 1.—IMPORTS OF ALMONDS INTO THE U.S.

Crops of 1899 to 1917.]

The wood of the almond is very hard and strong, enabling the tree to bear
the weight of heavy crops where pruning has been given proper attention
during the formative period of the young tree. As with other fruit trees,
the almond is subject to heart-rot and care should always be exercised
to prevent the checking and cracking of large wounds and consequent
infection with decay organisms. The hardness of the wood makes it the
finest kind of fuel, and when old orchards are being dug up the returns
from the sale of wood often more than pay for the expense of digging and
cutting up the trees and burning the brush.

The nuts are of two general classes—sweet and bitter almonds. The former
is primarily the almond of commerce, though the latter is used largely
in the manufacture of almond oil and almond flavoring, as well as in
the manufacture of prussic acid. The bitter almond is also used largely
in nurseries as a rootstock upon which to bud the almond and some other
fruits.

For a long time there has been considerable evidence to show that some
varieties are always self-sterile while a few are sometimes self-fertile.
Work done in 1916 and 1917 by Tufts[1] shows that practically all
varieties are self-sterile and that some of the self-sterile varieties
are also inter-sterile. In these tests the principal commercial varieties
were used. Blossoms of each variety were pollenized with pollen from
its own blossoms and from each of the others. Checks were for natural
pollination with each variety. The important results of this work are
briefly summarized as follows:

The Nonpareil and I.X.L. are inter-sterile, although both are
inter-fertile with the Ne Plus Ultra.

The Languedoc and Texas are inter-sterile.

The I.X.L. and Peerless are practically inter-sterile.

The California has proved the best pollenizer thus far tested, for all
varieties that bloom near it.

The Drake is inter-fertile with the Nonpareil, I.X.L., Ne Plus Ultra,
Peerless and Jordan, the only ones tested.

The I.X.L. is inter-fertile with the Drake, Jordan, California,
Languedoc, Ne Plus Ultra and Texas.

The Ne Plus Ultra is inter-fertile with the California, Drake, I.X.L.,
Languedoc and Nonpareil.


REQUIREMENTS

While the almond is in many ways an easy tree to grow where conditions
are favorable, it is more particular in its requirements than most
common orchard fruits, and the grower may find it difficult to produce
a good, thrifty tree unless he chooses the proper location. Very often
it will grow well and make a fine healthy tree, but owing to unfavorable
conditions, will not bear regularly, if it all.

[Illustration: Fig. 2.—Seven-year-old Ne Plus Ultra almond in full bloom,
at the University Farm, March, 1915, showing distribution of blossoms
well down into center of tree. Paper bags cover blossoms pollenized by
hand.]


CLIMATE

_Heat._—Where the conditions of soil and moisture are favorable the
almond will endure the intense heat of the interior valleys and even of
the Imperial Valley, provided it is pruned properly to shade the main
branches so as to prevent sunburn. Where trees, by severe pruning, are
opened up suddenly to the intense heat of the summer sun, almonds will
sunburn, but if the necessary opening up is done gradually, the bark will
become inured to the new conditions without danger. The nuts grow and
ripen more satisfactorily in the greater heat of the interior than along
the coast.

_Frost._—The almond tree is hardy and will endure fully as much cold
as the hardiest peach without injury. Trees are found growing well in
Illinois, Ohio, New York and other Eastern states. In very favorable
seasons they may even bear fruit, though this happens very seldom, due to
the extremely early habit of blooming before the spring frosts are over.
The first warm weather seems to start the trees into bloom, especially
where the enforced dormant season of winter is very long.

The blossoms, on the other hand, are very tender. There is a great range
in the degree of frost which will cause injury, depending largely on the
condition of the tree during the time that the fruit buds are forming and
developing, as well as on the duration and severity of the frost. Buds
and blossoms on trees which have been forced into premature dormancy,
either by lack of moisture or by severe attacks of red spider, are much
more susceptible to frost than those on trees which have continued
growth late enough in the fall to provide for the proper development and
maturity of the buds. After differentiation of fruit buds commences in
the summer, the almond leaves should remain on the tree until late into
the fall in order to strengthen and develop the fruit buds and store up
the elaborated food material for the use of the buds in their normal
development through the winter. Studies of almond buds gathered from
healthy trees which held their leaves until late fall frosts at Davis,
showed the first evidence of differentiation between fruit and flower
buds commencing about August 18, while the flower was not completely
developed until February 18 following. During the intervening time
development proceeded unchecked through the winter even though the tree
was apparently dormant. During the time the crop is ripening on the
trees, little is done toward storing food material for the buds. If the
leaves turn yellow or drop soon after harvest, the trees do not have the
opportunity of storing a sufficient supply of plant food for their normal
requirements and the buds are insufficiently nourished during the winter
period. The resulting buds are weakened and the indications are that they
are unable to endure unfavorable climatic conditions in the spring, such
as light frosts, continued cold weather or sudden changes from warm to
cold weather.

The most tender stage in the blossoming and development of the young
fruit seems to be immediately following the dropping of the calyx lobes
from the young fruit as it first commences to swell rapidly. The blossom
becomes more and more tender as it opens out and reaches the above stage.
After the young fruit has attained the size of a pea it rapidly becomes
more resistant to low temperatures. Blossoms with the petals exposed but
not yet opened have been known to stand temperatures of 24 degrees F.
and blossoms with petals beginning to fall have stood 28 degrees F. No
records are available as to the duration of these temperatures. In other
cases, blossoms with the petals falling have been killed by temperatures
of 30 and 31 degrees F. It must be remembered in this connection that
the almond blooms earlier than other orchard fruits and, therefore, is
often subjected to much more severe frosts than occur during the blooming
period of the later fruits. The greatest injury is likely to occur when a
frost follows one or more days of warm weather. When the mean temperature
both day and night remains low, frosts that might otherwise kill the
flowers or setting fruit do no harm. This is what occurred in February,
1917, at the University Farm, when repeated frosts at blooming time did
no harm whatever.

In determining the desirability of a location in regard to its freedom
from frost, the possibility of adequate air drainage is an important
item. For this reason the lands along the lower foothills immediately
above the floor of the valleys are ordinarily much less subject to
frost—because the cold air is free to drain away to the lower levels.
Generally the lands along the banks of streams which have been built
up higher than the other lands of the Great Valleys through which they
flow, are less subject to frost by reason of the natural flow of the
cold air from them to the lower lands adjacent. For the same reason the
planting of almonds in the lower lands of the valleys, no matter how
large the valleys may be, should be avoided, unless the locality has been
thoroughly tested for a long period of years and has proved to be an
exception to the rule because of some peculiar situation with favoring
air currents or air drainage, such as might exist near a natural draw
in the hills where the settling of the cold air in some portions of the
adjacent valley might be prevented. Such locations are generally confined
to very small areas. Oftentimes an opening or draw in the hills may
serve as an outlet for the drainage of much colder air from considerably
higher elevations beyond, and then the danger from frost is very greatly
increased. This is very common where cañons act as drains to conduct the
cold air from the high Sierras to the valleys below.

Variable weather conditions, and especially as regards temperature in
the spring after growth commences, are highly undesirable. Warm weather
immediately followed by cold tends to produce sour-sap, fruit drop and
kindred physiological ills. Oftentimes crops have been lost where no
frosts occurred after blooming commenced, simply due to sudden changes
in the weather. However, it is highly probable that the greater portion
of the trouble with fruit dropping, when of the size of peas or larger,
is due to improper pollination. When the soil is not sufficiently well
drained at such a time, the sour-sap effect is greatly augmented.

_Humidity._—Foggy or moist weather during ripening or harvesting is
highly objectionable. The nuts do not dry out rapidly enough on the trees
to prevent the growth of molds and consequent darkening of the shells.
The nuts then require much heavier bleaching to brighten them properly
for the demands of the market. The damp weather prevents the rapid and
thorough drying-out of the kernel; the sulphur fumes are absorbed by the
moist kernel and it sometimes becomes rancid before it is six months old.

Much damp weather in the spring encourages the growth of “shot-hole”
fungus in the blossoms and fruit, often causing the loss of a
considerable portion of the crop; the loss of leaf surface from the
fungus infection is sometimes so great as to materially affect the vigor
and vitality of the tree.

_Rainfall._—It is impossible to state any definite amount of rainfall
which will or will not maintain the trees and enable them to bear regular
crops of nuts, for so much depends not only on the variation in rainfall
in different sections and in different years, as regards distribution
throughout the year, but also on the time and intensity of the fall,
the character of the weather following the rains and the ability of the
soil to receive and retain the rain that falls. Ordinarily, however,
with the above factors favorable, it is conceded that where the winter
rainfall averages sixteen inches, almonds can generally be grown without
supplementing the water supply by irrigation, if the orchardist exercises
reasonable care to conserve the moisture for the use of the trees. Where
the rainfall is inadequate some means of irrigation must be found to make
up the deficit.

In some sections the annual rainfall varies greatly from year to year.
Often it falls in such a way that a large proportion of it is lost in
the surface run-off. In many places the soil is so leachy that it is
incapable of holding sufficient water for the use of the trees throughout
the summer, much of the winter rainfall being lost in the underground
drainage. Under either of these conditions, 40 inches of rainfall might
not be sufficient. Very often winter rains are followed by desiccating
winds so that a considerable portion of the rain which falls is lost by
evaporation before anything can be done to hold it.

Continued rainy, damp and cold weather at the time of blooming is
apt to sour the pollen or actually wash it away and thus prevent the
fertilization of the blossoms, without which a crop is impossible.
Bees and other insects are the principal means of accomplishing the
pollination of almonds and such weather prevents them from working.


SOIL

The almond is a deep-rooting tree and draws heavily upon the
plant-nourishing elements of the soil. In ripening the large number of
seeds which it is required to do, the tree must draw upon a considerable
area of soil in order to supply the large amount of mineral matter that
is needed to develop and mature the seeds. Analyses of almonds, as
compared with other commonly grown fruits and nuts, made by Colby,[2]
show that the almond leads in the total quantity of mineral matters
withdrawn from the soil. Colby further states that “The stone fruits fall
much below the almond in total ash (mineral matter) excepting the olive,
the ash of which, however, is largely silica (nearly eight-tenths), an
ingredient so plentifully distributed in all soils that it is of no
pecuniary value.” Table I illustrates this statement.

These figures suggest the necessity of having a deep, rich, well-drained
soil for best results. For this reason and because of the deep-rooting
habit of the almond, the soil should be at least ten or twelve feet deep.

_Hardpan._—Compacted substrata in the soil, whether they be hard clay
layers or cemented layers of silicious, ferruginous or calcareous origin,
are objectionable. They not only prevent the roots from foraging to a
considerable depth as they normally tend to do, but they prevent proper
drainage and aeration of the soil. If such layers are comparatively
thin, that is, not more that two or three feet thick at the most, they
may be shattered with dynamite so as to allow the moisture, air and
roots to penetrate to the better soil below. Hardpan, therefore, should
be avoided where it is too thick to be broken up or where it is not
underlaid by desirable soil.


TABLE I

SOIL INGREDIENTS EXTRACTED BY THE ALMOND AS COMPARED WITH OTHER ORCHARD
TREES, AS SHOWN BY ANALYSIS OF 1000 LBS. EACH OF THE CROPS IN A FRESH
CONDITION

                                           Phosphoric   Total
                          Potash,   Lime,    Acid,       Ash,   Nitrogen,
    Fruit                  lbs.      lbs.    lbs.        lbs.    lbs.

    Almond (hulled)        5.49      1.72    4.33        15.00    16.40
    Almond (not hulled)    9.95      1.04    2.04        17.29    17.01
    Walnut (hulled)        1.50      1.81    2.78         7.50    10.20
    Walnut (not hulled)    8.18      1.55    1.47        12.98     5.41
    Chestnut (hulled)      3.72       .71    1.89         8.20     8.00
    Chestnut (not hulled)  3.67      1.20    1.58         9.52     6.40
    Prunes (green)         2.66       .13     .53         4.03     1.48
    Apricots (green)       2.83       .18     .71         5.16     2.29
    Olives                 8.85      2.32    1.18        94.63*    5.85

    * 80.7 pounds of which is silica.

_Humus._—A plentiful supply of humus in the soil is essential. It not
only improves the physical condition of the soil, but assists drainage,
moisture retention and in rendering the plant food available in
sufficient quantities for the use of the trees and for the maturing of
full crops of almonds. Many orchards have been very light producers year
after year because of a deficiency of humus in the soil.

_Drainage._—The almond root is very particular as to its air and moisture
requirements in the soil. It will not endure standing water in the soil
for any length of time, especially during the growing season. Exclusion
of air by excessive moisture is believed to be one of the most productive
causes of “sour-sap.” If allowed to continue for any length of time such
conditions will cause the death of many or even all the roots and with
them the top.

_Water Table._—A factor which is very commonly overlooked in connection
with the natural drainage of almond lands is the position of the water
table at different seasons of the year. Great care must be exercised in
choosing a location to be sure that the water table does not rise during
the summer. This is a very serious problem in many irrigated sections.
Where the water table during the winter months is less than 12 feet in
depth it is highly desirable to have as little fluctuation as possible.
Where fluctuations take place at a greater depth than 12 feet they are
not generally serious. The ideal condition is where the water table is
highest in the winter and quickly drops after the winter rains are over,
to a depth of from 10 to 12 or 15 feet, remaining at that point during
the remainder of the growing season.

The soil in addition to being well drained, must be sufficiently
retentive of moisture to supply the tree throughout a long, dry
growing-season. If the soil will not retain a sufficient amount of the
winter and spring rains, recourse must be had to irrigation to supply the
deficiency.

_Alkali._—Alkali lands are unsuited to almond culture and should be
carefully avoided.

In summarizing the soil requirements for almond culture, it may be
stated that the ideal almond soil is a medium loam, uniform in texture,
or nearly so, to a depth of at least twelve feet, well drained and
yet retentive of moisture for the use of the tree during the summer.
Fortunately some of the best almond soils are situated along stream banks
where the land is relatively high, and is, therefore, less subject to
frost. These streams flowing from the mountains and foothills have built
up their own beds by the detritus brought from the hills. The coarser
particles being deposited first and nearest the stream itself, make the
better drained soils, while the finer particles and the clays, deposited
further back from the bank and in the lower lands, form the heavier soils.

The various conditions mentioned above are what the tree should have for
best conditions of growth and production. Oftentimes these conditions
may be approached without the soil being as deep as ten or twelve feet.
Exceptions to this will be mentioned in discussing the various almond
districts of the state. It is essential to understand that trees,
while growing and bearing on shallow soils in some localities, do so
because of other exceptionally favorable conditions; either the soil is
exceptionally well drained and yet sufficiently retentive of moisture, or
the humus in the soil is plentiful and the roots are able to work into
the underlying partially decomposed rock for moisture and some plant
food. In such localities the trees bear comparatively well because of the
exceptional freedom from frost in the spring. Trees in these localities
are generally smaller than on the deeper, richer soils, and where other
conditions are equal, they bear crops in proportion to their size.


ALMOND DISTRICTS

Almonds are grown in nearly every county in California. In some counties
the few trees growing only occasionally succeed in producing a crop of
nuts. There are sections in nearly all parts of the state, however,
where they are a success commercially. Within these sections may be
found desirable and undesirable locations, depending upon soil and
moisture conditions and freedom from injurious frosts. Any discussion of
a district, therefore, does not necessarily mean that all lands within
that district are uniformly adapted to almond culture. On this account
it is impossible to define a district any more closely than to name the
center and include with it the outlying districts. In the same way it is
sometimes impossible to say just where one district begins and another
ends. Adaptability of any special location can be determined only by
careful study of the land itself and diligent inquiry of those familiar
with it.

As far as possible, districts should be chosen where a definite cold
winter season exists. Warm weather and lack of freezing temperatures do
not hold the trees fully dormant and any frequent occurrence or unusual
continuation of spring weather in the winter will start the trees into
growth; cooler weather following, interferes with the normal flow of sap,
results in injury to the tree and blossoms, and often causes gumming
of the nuts which mature. This condition exists largely in the lower
elevations in Southern California and especially in the coastal portion,
where the ameliorating influence of the Pacific is felt. This same
condition exists close to the coast in the northern portion of the state.
Further inland and at higher elevations the winters are more pronounced,
and where these are not too severe or prolonged the almond thrives best.


SACRAMENTO VALLEY AND FOOTHILL SECTIONS

Commencing in Solano County, about eight miles northwest of Suisun and
extending as far north as the southern end of Shasta County, close to
the base of the foothills on the west side of the Sacramento River, are
a large number of orchards on the bottom lands of the valley. These are
found principally on the higher lands along the banks of streams flowing
from the Coast Range in a generally easterly direction to the Sacramento
River. The two most important streams of this type are Putah Creek,
forming the boundary between Yolo and Solano counties, and Cache Creek,
flowing through the Capay Valley and across Yolo County to the Sacramento
River.

These plantings being on the floor of the valley are more subject to
frost than the foothill plantings, but they have the advantage of being
on the rich valley soils, and while they may lose a crop occasionally
from frosts, they make it up in the long run by the much larger growth of
the trees and their ability to produce larger yields. Many orchards do
not show any such ability to produce large crops, but such a failure must
be attributed to lack of pruning and care, rather than to any inherent
inability of the large trees to produce nuts. Again, trees on the rich
and moist bottom lands may be kept so vigorous and healthy by good care
that they are apparently able to endure lower temperatures than less
vigorous trees on the shallow and poor upland soils where frosts are less
common or severe.

Many recent plantings have been made along the lower foothills on the
west side of the Sacramento Valley. The three most important districts
where these plantings have been made are west of Dunnigan, Arbuckle
and Corning. The plantings in these districts are mostly on a gravelly
clay or clay loam soil which is not as rich nor generally as deep as
the bottom lands and, consequently, the trees are somewhat smaller, but
they have the advantage of freedom from spring frosts due to superior
air drainage. The problem in this district is chiefly one of moisture
retention by cultivation, as in most cases the growers are unable to get
water for irrigation at a reasonable cost, if at all.

The valley districts extend to Tehama County and down the east side of
the Sacramento River, the same as on the west side, the principal centers
being at Chico, Durham, Liveoak, Pennington and Sutter. Parts of the
Liveoak section are too low and many orchards have suffered from poor
drainage both of water and air.

The foothill sections on the east side are principally around Antelope,
Fairoaks and Orangevale in Sacramento County and the southern end of
Placer County. Here the danger from frost is slightly greater than on the
western foothills because of the proximity to the snow-covered Sierra
Nevada Mountains. On the other hand, water from the Sierras renders
irrigation possible at a reasonable cost, so the trees can be kept in
good condition. Care must be exercised here to avoid frost pockets. There
is also danger of poor soil drainage in the swales.


SAN JOAQUIN VALLEY AND FOOTHILL SECTIONS

Conditions here blend very much into those of the Sacramento Valley
sections. Continuing south there are plantings around Acampo, Lodi,
Stockton, Linden, Ripon, Modesto and more scattered plantings farther up
the valley. The danger from spring frosts increases southward due to the
earlier blooming of the trees. In some of these sections, notably around
Ripon and Modesto, the excessive use of irrigation water for alfalfa and
other crops has resulted in a rise of the water table in many places
until it is within a foot or two of the surface during the summer months,
and in many other places comes to within four feet of the surface.

On the west side of the San Joaquin Valley the principal plantings have
been in eastern Contra Costa County. Most of these orchards are of old
trees, planted from 15 to 30 years ago. In order to obtain satisfactory
air and soil drainage the orchards were planted on the rolling hills,
the soil being nearly all blow-sand. Irrigation is too expensive to be
installed on most of this land, and the problem in that section is to
conserve moisture and at the same time hold the soil in place and prevent
it from being carried away by the wind.

[Illustration: Fig. 3.—Typical hillside orchard of Jordan almonds near
Los Gatos. Trees are variable in size, and some are missing. In the right
foreground is a typical spot of missing trees resulting from Oak fungus
infection.]


THE COAST SECTION

Almonds were planted quite extensively in past years in many of the coast
valleys, such as the Santa Clara, and where they were protected from the
direct influence of the moist ocean breezes, they apparently did well.
Later most of these orchards were replaced by prunes and apricots as they
were generally found to be better paying crops in these valleys. On the
hills, however, many typical hillside orchards remain, as shown in figure
3.

Localities directly affected by the coast breezes have proved themselves
to be unfit for commercial almond culture.


INTERIOR COAST VALLEYS AND HILLS

Back from the coast in the smaller valleys and on the hills where the
coast fogs seldom reach, many locations may be found where almonds are
producing successfully. These favorable localities are scattered, owing
to lack of proper soil or moisture conditions.

_Paso Robles District._—The one outstanding district in the coast hills
where the almond is being grown successfully is in the country west of
Paso Robles. There, at an elevation ranging from 900 to 2000 feet, where
there is sufficient air drainage to the considerably lower land near
by, the almonds are doing well. These plantings are, in most cases, on
a comparatively heavy soil, sometimes approaching adobe, and underlaid
by marl. This limestone formation is quite permeable to both water and
the roots of the trees, and the rock itself acts as a sponge and holds
considerable quantities of moisture. On the other hand, consisting of
steep hills, the land is excellently drained and the trees seldom suffer
from standing water around the roots.

The chief objection is that most of this land is very shallow, generally
ranging from two to four or five feet deep. In some places almonds are
found growing where the marl is so close to the surface as to be turned
up by the plow. This makes the retention of moisture for the use of the
trees a serious problem. The trees do not attain large size on such soils
and the nuts are inclined to be somewhat smaller than normal. The steep
character of much of the land makes tillage and spraying rather difficult
and expensive. As long as the price of the land is kept down to a
reasonable figure, the grower can afford to put more money into the care
of both land and trees. It must be thoroughly understood that there are
many localities close to Paso Robles that are greatly subject to frost
and hence not at all suited to almond culture. This is especially true of
the lands directly around and east of Paso Robles, and also of any of the
comparatively low lands throughout the district.


SOUTHERN CALIFORNIA

The entire coast district of Southern California has practically proved
itself to be unfitted for almond culture, except at elevations above 1500
or 2000 feet. The limiting factor seems to be the lack of a sufficiently
definite winter season at the lower elevations. Trees are inclined to
bloom too early in the season or before the winter is over.

Above 1500 or 2000 feet the increased elevation gives a sufficiently
definite cold winter season and the trees tend to blossom at more
seasonable times. Aside from scattered plantings in the hills of San
Diego County and a few orchards around Hemet and San Jacinto in Riverside
County, the principal plantings are at Banning and in the Mojave Desert.

_Banning District._—Within a radius of three miles of Banning, with an
average elevation of 2300 feet, where a plentiful supply of water is to
be had from the mountains to the north, are a large number of orchards
ranging in age from 2 to 29 years. The bulk of the plantings were made
during 1910 and 1911. This is the oldest district in southern California
and has proved itself to be well fitted for almond culture.

_Antelope Valley and Vicinity._—The old plantings in the Mojave Desert
are few and far between. They have, however, served as an impetus for
large plantings in recent years many of which have turned out to be
failures. This happened in many portions of Antelope Valley, west of
Lancaster, on the Southern Pacific Railroad in northern Los Angeles
County. Many more of these plantings are young and still have to prove
themselves.

Orchard almond trees are never grown from seed, as they do not reproduce
true to type, but are propagated by budding desirable varieties on
seedling roots in the manner commonly employed in nursery practices for
other stone fruits, like the peach. Every grower must decide, however, on
what rootstocks he will plant his trees.


ROOTSTOCKS

There is much to learn yet regarding the behavior of the different
roots under varying conditions when used as stock for the almond, but
sufficient information has already been gathered to permit of certain
recommendations being made.

_Almond Root._—The greatest proportion of almonds in this state are
on almond roots. Where the most desirable soil, moisture and drainage
conditions exist it is best to select the almond root. It will live
in comparatively dry soils, but cannot be expected to make a tree of
large size or bear crops of nuts if the dry conditions continue. Where
irrigation is not available, and the soil is deep and of proper texture,
sufficient moisture may be retained in most years by cultivation to
enable the tree to grow and bear fruit. When extra dry years come, the
almond root may not enable the tree to grow or produce any better than
would another kind of root, but it will carry the tree over a few dry
seasons as well or better than any other. Then, when sufficient moisture
does come, the almond root is ready to start the tree off in its normal
course with the least loss of time.

[Illustration: Fig. 4.—Languedoc almond on peach[3] root; typical of
other trees in same orchard, near Davis. Planted about forty-seven years
before. Compare with trees in same orchard on Myrobalan root, as shown in
Fig. 5.]

The bitter almond is often recommended as being superior to the sweet
almond as a stock. This claim has never been proved. Experiments indicate
that there is fully as much variation between the bitter almond seedlings
grown from seed from different trees as there is between seedlings from
bitter and sweet almonds. Both are equally subject to attack by gophers.
The grower’s chief object, therefore, should be to secure as healthy,
vigorous trees as possible whether they be on sweet or bitter almond
roots.

_Peach Root._—Where the soil moisture is quite variable in different
portions of the soil, or variable from time to time during the growing
season, the peach root will probably be most satisfactory. Soils less
than six or eight feet deep, or where gravelly or hardpan layers occur
at less depths, are not satisfactory in most cases for the almond root,
and under these conditions the peach root is better. The peach root is
a little better where irrigation is practiced during the summer, and
especially so where there is danger of slow drainage of excess water
from the soil. The peach does not thrive with standing water around
its roots, but will better withstand fluctuating or temporary extremes
in water supply than the almond. Its union with the almond is entirely
satisfactory. See figure 4.

[Illustration: Fig. 5.—Languedoc almond on Myrobalan root, typical of
many other trees in same orchard, near Davis, planted about forty-seven
years ago. Compare with trees planted same time on peach root as shown in
Fig. 4.]

_Davidiana Root._—Within the last five or six years the United States
Department of Agriculture has introduced the seed of a Chinese peach,
_Prunus davidiana_, the root of which is more resistant to alkali than
the ordinary peach. This has been found to unite readily with the almond,
although experiments have not yet gone far enough to fully determine its
true value. It gives promise, however, of being a very desirable stock
for sections where alkali may be troublesome.

_Undesirable Roots._—The Myrobalan plum has frequently been recommended
as a stock for the almond on poorly drained soils. The two make a strong
union, but the plum root grows much slower than the almond top, as
indicated in figure 5. A comparison with figure 4, in which both trees
are 48-year-old Languedoc, shows that the trees on Myrobalan root are
pinched-in below the union while those on peach root are swollen at the
base. Even young trees show the same pinching-in below the union. Almond
trees on Myrobalan root do not make as large trees nor do they bear
satisfactory crops in any portion of the state where it has been possible
to compare them with the same varieties on other roots in similar
situations.

The apricot is occasionally recommended because of its strong, thrifty
growth, but it is a mistake to attempt to use it, as the union is not
satisfactory. The trees grow thriftily for awhile, but before they reach
full bearing they either break off at the union or are blown over above
the union by moderate winds.


TOP-WORKING OLD TREES

Often through injudicious selection of varieties for original plantings,
or for some other reason, it becomes desirable to work over old trees to
more desirable varieties. This may be done by budding or grafting. In
either case the tree may be entirely reworked in one season or one-half
may be done the first season and the other half the next. The almond
will recover fully if completely deheaded to a height of from five to
six feet from the ground, provided it is not subjected to severe winds
or excessive moisture in the soil. Winds are liable to break off the
new top during the first year or two. Where these are dangerous it may
be well to leave half of the tree on the windward side to be worked the
second season. The remaining portions will help to serve as a wind-break
until the top-worked portion of the tree has a chance to unite solidly
with the stub of the main branch to which it is attached. Where winds
are not likely to do damage it is generally the most economical method
to work over the entire tree at one time. If the roots are subjected to
excessive moisture conditions during the first season, the new growth may
be unusually vigorous and much more likely to be blown out as a result of
the heavy top and the poor attachment to the stub. “Sour-sap” may also
be very serious. Under such conditions leaving half the tree the first
season will enable it to distribute the growth more evenly with less
undesirable forcing.

Whether the top-working shall be done by budding or grafting depends
largely upon the wishes of the grower and the skill of the workman.
Grafting will give a new tree more quickly than budding, because by the
latter method a year is lost in growing a supply of new wood on the stubs
into which the buds must be placed. By grafting, the new scions may start
growing the first spring without any delay. Ordinarily the best method
is to graft the trees the first winter and then, where the grafts fail
to grow, buds may be inserted in the new growth which will come from
the stub. During the first two seasons especially, great care must be
exercised to keep out the sprouts that interfere with the growth of the
scions. At the same time, all water-sprouts should not be removed during
the first summer or there will not be sufficient leaf surface to perform
the necessary functions of the tree. In addition, the scions tend to grow
so rankly that they will be top-heavy and much more liable to be blown
out by the wind, as shown in figure 6. This may largely be prevented by
pinching the ends of the new scion growth during the early summer to
force lateral branching. At the end of the first year all water-sprouts
should be removed leaving nothing but the growth from the scions.

[Illustration: Fig. 6.—Twenty-seven-year-old trees deheaded two years
before, showing the break-off of the new growth by strong winds.]


PLANTING

The usual preparation given land for orchard purposes prior to planting
should be applied to land being prepared for almonds. Special care must
be given to insure thorough aeration of the subsoil by breaking up all
hardpan, plow-pan or other compacted layers in the soil, where possible.

[Illustration: Fig. 7.—Almonds planted twelve feet apart. Trees in very
weak condition and almost entirely defoliated by mites before harvest.
The few nuts ripening on the trees are small “sticktights.” Photo taken
September 21, 1915.]

_Distance._—Almonds in most soils should be planted 30 × 30 feet on the
square. In rich, deep soils the trees quickly fill the intervening space,
the roots occupying the entire soil area long before the tops touch. In
poor, shallow soils, or soils deficient in available moisture, the trees
may not occupy the entire area above ground, but the roots will require
more horizontal feeding space to enable them to make the size trees and
bear the crops that they should.

Trees planted too close together often abstract the moisture from the
soil before the growing season is completed. This shortage of moisture,
with the aid of mites, commonly called red-spider, causes the loss of
the leaves long before they normally should drop. Under such conditions
the fruit buds are unable to make the vigorous growth which they should.
These weak buds are unable to endure the degree of frost or other
unfavorable conditions that stronger ones withstand without serious
injury.

The trees must have plenty of sunlight and air. If planted too close, the
trees tend to grow too high, each one striving for the light which is
only available from above. In figure 7 the upward tendency of the trees
is clearly shown. Such trees, if pruned as they ought to be, have a much
greater tendency to send out numerous water-sprouts than trees which
have plenty of room for the tops to expand laterally. After the tops of
the trees interlock and shut out the sunlight from the lower portions,
the smaller branches and fruit spurs in those parts gradually weaken
and die, and eventually the entire crop is produced on or near the tops
of the trees, where direct sunlight is available, as shown in figure 7.
The excessive upward growth of the trees, with the consequent forcing of
the fruit bearing to the top, not only greatly increases the difficulty
and cost of pruning, spraying and harvesting, but reduces the possible
bearing surface of the trees.

_Setting the Trees._—The utmost care is necessary in setting out the
trees to secure a uniform stand of vigorous trees. The trees are planted
much the same as other deciduous orchard trees, but care must be used to
spread the roots well to secure a thorough compacting of the soil around
all the roots, and to see that the trees are not planted deeper than they
were in the nursery.


CULTURE

_Soil Handling._—The almond is one of the most exacting of fruits as
regards its cultivation. The assumption is very often made by growers
that because the tree will live through periods of prolonged drouth, it
will also thrive under careless or poor methods of cultivation. That
this is entirely erroneous may be inferred from the fact previously
referred to that the almond draws more heavily upon the plant food of
the soil for the ripening of its crop than any of the common orchard
fruits. Experience has abundantly proved that many almond orchards are
not bearing profitable crops because the requisite soil constituents are
not available in sufficient quantities during the long growing season.
The reasons for this condition may be one or several. First, there may
not be sufficient moisture available throughout the season, or it may not
be distributed evenly or in sufficient amounts throughout the entire soil
area. Second, there may be insufficient aeration of the soil; and third,
there may not be sufficient humus to fix the soluble plant food in the
soil and render it readily available as needed by the roots.

Proper distribution of moisture in sufficient quantities is essential to
secure adequate solution of the mineral elements needed by the roots for
the use of the tree in all its parts. Sufficient aeration is needed to
provide for the normal oxidation and weathering of the soil particles,
and also for the respiration of the roots themselves.

There seems to be no question about the value of spring plowing and
cultivation to put the soil in good physical condition, but many growers
apparently question the value of summer cultivation. Though the surface
of the soil appears to be unchanged after a period of several months,
the fact is entirely overlooked that the structure of the mulch has been
gradually changed and capillarity to the surface has been restored. The
result is that evaporation takes place so rapidly from soils in such a
condition, as well as from the leaves of the trees, that long before the
end of the season the moisture is practically gone.

The methods and tools used are much the same as for other orchard
trees and it is only necessary to call attention to items likely to
be neglected. Spring plowing should vary in depth from year to year
to avoid the formation of an impervious plow-sole. The depth to plow
ranges from a minimum of six inches to ten or twelve inches or more as
desirable. Summer cultivation should be kept up at least once a month,
and preferably oftener, throughout the summer months and the soil should
be stirred to a depth of four inches to provide a mulch sufficient to
hold the moisture effectively in the hot, dry climates where almonds are
grown. The actual number of cultivations necessary will depend on the
types of soil. Harness with projecting hames or broad singletrees or with
projections of any kind to catch on the branches or bark of the trees
should never be used in an orchard.

_Cover Crops._—Constant cultivation throughout the summer allows the
humus to be burned out of the surface soil and, by hindering the growth
of vegetation, prevents the addition of a natural supply of humus to
replace that which has been lost. It is necessary, therefore, that some
artificial means be used to supply the deficiency. The annual growth of
winter cover crops to be plowed in during the spring, while not entirely
replacing the humus burned out in the summer, serves to reduce the annual
loss and at the same time assists materially in improving the texture of
the soil.

A shade crop, such as alfalfa, may be grown successfully in mature
orchards where irrigation water is available, and where perfect drainage
of surface and subsoil can be maintained. During the first four or five
years or more such a crop is generally a detriment to the almond trees,
but after the trees reach maturity it may be beneficial in securing
better drainage and aeration of the soil by the penetration of the
numerous roots to considerable depths and their consequent decay when
it is plowed in. Alfalfa also supplies nitrogen to the soil and thus
gradually increases the fertility. The great danger with such a crop is
that the orchardist is apt to irrigate for the alfalfa at the expense of
the trees because of the quicker returns from the former. In deep, rich
soils the cuttings of alfalfa may be removed from the land, though the
last cutting in the fall should be allowed to remain on the land. Where
this is done, a natural mulch is obtained which helps to increase the
supply of humus. If the soil is poor and lacking in humus it is better
to leave more cuttings of the alfalfa on the ground to decay. As this
continues the soil becomes, through the increased accumulations of humus,
more permeable and yet more retentive of moisture, and less irrigation
will serve the trees more effectively.

During the early spring a well-established stand of alfalfa may assist so
materially in getting rid of the excess water in the soil that sour-sap,
fruit drop and kindred ills resulting from the unseasonable warm weather
while the ground is filled with water and the trees are starting into
growth, may be greatly reduced or avoided entirely.

_Irrigation._—Water for irrigating almonds must always be used with great
care whether it be in summer or winter. All water should be so applied
that it will readily spread through the soil and not remain in excessive
quantities for any length of time. Water should not be applied during
blossoming or setting of the fruit in the spring or within a week or
more of harvest. On the other hand, water applied just before the hulls
commence to open, where the soil has become too dry, greatly reduces
the number of sticktights, or almonds in which the hulls stick to the
ripening nuts without opening.

_Fertilization._—Little or no systematic work has been done up to the
present time in the use of commercial fertilizers on almonds. The use of
barnyard manure is desirable wherever obtainable. The value of almond
hulls as fertilizers is doubtful because of the difficulty of bringing
about their thorough decay when applied in sufficient quantities to be
worth while. The use of lime to correct soil acidity and for improving
the texture of heavy soils will be found desirable where this is
obtainable at reasonable rates.


PRUNING

The almond trees normally set a larger number of fruit buds than they
are capable of maturing. The number of blossoms set on a healthy tree to
produce a full crop will be generally not more than 20 per cent of the
total number which opened in the spring, and oftentimes much less. It has
frequently been noted that trees which are somewhat lacking in vigor are
inclined to set a larger number of fruit buds than those that are strong
and vigorous. The normal set of blossoms on a young, vigorous tree is
shown in figure 2. The result is that with the sub-normal strength of
such trees being distributed among the extra number of fruit buds, the
latter are not able to develop into the strong, healthy buds they should.
The results of such conditions have been discussed on pages 23, bottom,
and 24, top. One of the best means of securing and keeping healthy,
productive trees is by careful, thoughtful and systematic pruning. The
treatment given most of the almond orchards would indicate that the
growers consider pruning to be one of the least important of the cultural
practices.

[Illustration: Fig. 8.—Typical Drake almond tree in University Farm
orchard; nine years old.]

[Illustration: Fig. 9.—Typical Languedoc almond tree in University Farm
orchard; nine years old.]

To be most effective, pruning must be followed systematically throughout
the entire life of the tree. The details of the practice will vary
greatly, depending on the soil, moisture and climatic conditions
surrounding the tree, as well as other treatment accorded it. At planting
time, it is generally agreed that the tree should be cut back to between
18 and 24 inches from the ground to reduce the top to correspond to the
shortened root system and to form a low head for the tree. A low head is
desirable to avoid sunburn of the trunk and to keep the tree within easy
reach for pruning, spraying and harvesting. During the first summer in
the orchard much can be done to obtain a well-balanced head, to get the
main branches well spaced on the trunk, and to prevent crowding later on,
by pinching out all undesirable growth as fast as it appears and forcing
the growth into those parts of the tree which are to remain. If these
branches tend to grow too long and willowy, they may be made to branch
by pinching back when they attain the desired height. In this way, if
the tree can be kept growing vigorously, the beginning of an excellent
foundation framework may be developed the first year.

[Illustration: Fig. 10.—Typical Nonpareil almond tree in University
Farm orchard; nine years old. Note numerous water sprouts which must be
removed.]

[Illustration: Fig. 11.—Typical I.X.L. almond tree in University Farm
orchard; nine years old.]

The following winter, when the tree is one year old in the orchard, if it
has grown too vigorously and the branches are too long and willowy and
not properly branched it should be headed back to improve the shape and
symmetry of the whole tree. If the tree has not made sufficient growth
to give it a properly shaped head, it should also be cut back even more
severely than in the case of the too vigorous growth. There sometimes
will be trees that during the first year will develop such a well-shaped
and stocky frame that no further heading will be necessary, all future
pruning being limited to thinning out undesirable and interfering
branches. Ordinarily, however, it will be highly desirable or necessary
to continue the practice of heading-in the yearling tree at least. As
long as heading continues it will pay to give special attention to
pinching and thinning the following summer. In this way the frame of the
tree may be developed more quickly and the future necessity of heading be
materially lessened. In rich bottom lands where moisture is plentiful,
heading may be necessary when the tree is two, three and, in extreme
cases, 4 years old, in order to spread the tree and prevent it from
growing too high. The necessity for this can only be determined by a
careful study of the tree itself and the conditions surrounding it.

[Illustration: Fig. 12.—Typical Ne Plus Ultra almond tree in University
Farm orchard; nine years old.]

The habit of growth of a given variety will have a great deal to
do with the number of seasons during which heading back will be
practiced. Spreading varieties, such as the Drake (see figure 8), if
making a strong, vigorous growth, should not be headed any longer than
is necessary to start a sufficient number of main branches. Every
opportunity must be given the trees of this variety to grow as upright as
possible. Summer pruning of the drooping, undesirable branches wherever
they develop, will help to increase the growth of the upright branches.
By pruning as far as possible to inside buds, every opportunity will be
given the trees to grow upward. If trees of such varieties make a poor,
weak growth, a very heavy heading will force them to make a stronger and
more vigorous growth the following season, provided any unfavorable soil
and moisture conditions are corrected. Care must be exercised with these
trees to prevent the downward growth of any of the branches by pruning
them off during the summer, as suggested above. As soon as a strong,
upright growth is started, no further heading should be done, but careful
thinning by removal of undesirable growth should be continued.

Upright varieties, such as the Languedoc (see figure 9) and Texas, may
require heading for a longer time than the more spreading varieties. It
is necessary to force them to branch nearer the ground and they should be
made to spread as much as possible. Pruning to outside buds and summer
pinching will aid materially and make it unnecessary to head back after
the first two or three years. Where this is not done, heading may be
necessary at the end of the third and possibly to the fourth year if the
tree is in rich, deep, moist soil. Another advantage of summer pinching
and removal of water sprouts is that the trees are not allowed to develop
a thick “crow’s nest” at the end of the stubs where heading back was done
the previous winter, making the following winter pruning much easier. The
habit of growth of each of the principal commercial varieties is shown in
figures 8 to 12, inclusive.

After the main framework is properly started, further pruning will be
limited to thinning out the tree to keep it sufficiently open and to
remove all dead, injured and interfering branches. Most of the growth
after this will continue from the ends of the remaining branches and as
the trees grow higher they will tend to branch more. All cross branches
and those that are liable to interfere later should be taken out. All
water sprouts should be removed unless they are needed to fill in
undesirable open spaces.

As the trees come into full bearing and approach maturity, the vigorous
wood growth will cease and will be replaced by a moderate yearly growth
of wood which will gradually increase the size of the tree without making
it unmanageable. Where trees continue to make excessive wood growth when
they should be bearing, the trouble may generally be traced to unusually
rich, moist soil, a condition which pruning cannot correct. It may be
beneficial to stop pruning altogether for a few years, which will be
likely to throw the trees into heavy bearing and thus stop excessive wood
growth. After the bearing habit is once thoroughly established, moderate
pruning may be done to get the tree back into proper shape.

[Illustration: Fig. 13.—Eighteen-year-old almond trees deheaded six feet
from ground, in the Armstrong orchard near Davis. Stubs painted with
white lead. Photo taken February, 1914. Compare with Figs. 14 to 19.]

[Illustration: Fig. 14.—Same trees as Fig. 13, showing growth one year
after deheading. Photo taken March, 1915. On some of the trees long
stubs were left near the bottom of the trees from which new growth never
started. Only a moderate thinning out of the new growth was done.]

The mature tree should have its branches so spaced that sunlight may
penetrate to all portions of the tree. This is necessary for the
continued health and life of the fruit spurs in the lower portions of the
tree. If the top is too dense, the new growth can only continue in the
top and outer portions of the tree where sunlight can penetrate. When
an adventitious bud does start in the center of the tree it immediately
makes a strong vigorous growth to reach the sunlight far above. Such a
growth is called a water sprout. If the trees are kept so pruned that
the shadow on the ground during the greater part of the day is mottled
with sunlight while the trees are in full leaf, the small growth may be
maintained in the center and the bearing surface greatly increased. Where
this is done the trees will not tend to grow as high as they otherwise
would. Pruning of healthy, mature trees, therefore, will be limited to
thinning out and removal of dead and interfering branches and water
sprouts. Portions which grow too high may be brought down by removal
close to a shorter and lower branch. By giving this treatment only to
small portions of the tree during a season, the forcing of water sprouts
may be largely avoided.

[Illustration: Fig. 15.—Same trees as Fig. 14, showing two seasons’
growth after deheading. Photo taken February, 1916, just after pruning
had been completed.]

Old trees, or those which, through improper care or neglect have become
weak and unfruitful, may often be rejuvenated. One method is to dehead
them to a height of about six feet from the ground and to grow entirely
new tops. By this method about three years are required to bring the
trees back to the point where they are again ready to bear profitable
crops. The objections to this are that it is an expensive operation, no
crops whatever can be obtained for two years, organisms of decay may gain
entrance to the wood, and sometimes the sudden shock to the tree renders
it more subject to physiological disturbances. The advantages are that if
proper care is given the trees during the rebuilding period, much better
formed trees may be obtained and a finer quality of bearing wood be
secured throughout the new trees.

[Illustration: Fig. 16.—Same trees as Fig. 14, showing three seasons’
growth after deheading. Photo taken January, 1917. No pruning done this
winter. Trees have not borne more than a few almonds but have a good set
of fruit buds.]

To be successful, the deheading process must be followed by careful
thinning of the sprouts that will be forced from the old stubs. If too
much thinning is done the first year, there is danger of those that are
left becoming top-heavy and breaking off. This is especially troublesome
in sections subject to strong winds. The new sprouts should be left
sufficiently thick to help support each other, and yet should be thinned
out sufficiently to prevent crowding. At the end of the first season’s
growth, further trimming should be done, giving those branches best
adapted for the frame of the new tree a chance to take the lead the
following season. A sufficient amount of secondary growth should be left
to help take care of the excessive sap flow in the shortened tree, but
this must be watched to see that it does not interfere with the growth
which is to be permanent. By the end of the second year, the permanent
branches should be sufficiently strong and firm to permit the entire
removal of all other branches. The amount of wood to be left until the
end of the second season and then removed is clearly shown in figures 18
and 19. The third year the tree should make sufficient growth to restore
very largely the equilibrium between the top and the roots and also
produce a small crop. Figures 13 to 17, inclusive, illustrate the steps
in rejuvenating an orchard by the deheading process from the start until
the trees are again in commercial bearing.

[Illustration: Fig. 17.—Same trees as Fig. 14, showing four seasons’
growth after deheading. Photo taken December, 1917, after trees have
borne their first good crop of nuts. No pruning has been done since
January, 1916.]

Some growers find it more desirable to cut back only one-half of each
tree at a time. The shock to the tree is not so great and the liability
to sour-sap correspondingly less. The halves of the tree left standing
act as a wind-break to prevent the blowing out of the new growth, which
at the same time is less likely to break off because of its slower and
more sturdy growth. The objection to this method is that the other half
must be cut off the following winter and the shaping process is more or
less uneven, and necessarily continued over a long time.

[Illustration: Fig. 18.—Two seasons’ growth before pruning of almond
trees deheaded six feet from the ground January, 1914, in the Armstrong
orchard near Davis. The tree was only moderately thinned at the end of
the first year. Photo taken February 2, 1916.]

The other method of rejuvenation is to thin out gradually the dead and
weakened branches in the old trees and rebuild them gradually, removing
only a small portion in any one year. As the new growth is forced out it
is used to replace the old wood where possible. Such a system requires
more cutting of small branches high up in the tree to be successful, for
it must not be opened to sunlight too suddenly or sunburn will result.
The cutting of a large number of small branches tends to force the growth
of new buds over a large proportion of the tree and if done moderately
many of these will quickly develop into fruiting wood. Eventually, many
large branches may have to be removed as newer branches are developed,
but this must necessarily be a comparatively gradual process. The
advantages of this method are that there is no sudden shock to the tree,
there is always sufficient leaf surface to care for any extra supply of
sap which may be forced into the tree by unfavorable weather and moisture
conditions, and cropping will be continuous.

[Illustration: Fig. 19.—Same tree as Fig. 18 after pruning. The actual
time required to prune this tree was twenty-five minutes. Photo taken
February, 1916.]

Whatever method of rejuvenation is used, the grower must be very
careful from the first to protect all large wounds by some paint or
other protective covering, such as asphaltum, to prevent checking and
weathering and to keep decay from getting started and working into the
heart of the tree. With very large wounds a protective covering must be
kept on during the remainder of the life of the tree, or until the wounds
heal over completely.


INFLUENCE OF CULTURE ON NUTS

The effect of culture on the nuts is quite marked. All varieties will
vary in size from season to season and in different orchards during the
same season, depending on the plant food and moisture supply available
during the time the nuts are maturing. Some varieties, notably the
Nonpareil, will vary more in size than in plumpness, while other
varieties, like the Ne Plus Ultra, are more inclined to produce somewhat
shriveled kernels and imperfectly developed shells and the variation
in size will not be as great. As the trees bear larger crops the nuts
produced are inclined to be smaller. Young, vigorous trees with a light
crop will often produce unusually large nuts with comparatively thin
shells. The value of a variety, therefore, will depend largely upon its
behavior after the trees reach full maturity and bearing.


ORCHARD HEATING FOR FROST PREVENTION

There has been considerable interest in protecting almonds from frost
because of the frequency with which they are subjected to such conditions
by reason of their early blossoming habit. The use of orchard heaters
in some districts has become a common and successful practice. It is
possible to economically control several degrees of frost for three or
four nights or possibly more by a judicious use of heaters.

The best type of heater for almond orchards has not been thoroughly
worked out as yet, but the reservoir heaters of the Bolton or Hamilton
type have been commonly and successfully used. The former are commonly
known as “pots.” At least 75 one or two-gallon heaters per acre are
necessary to control temperatures as low as 27 or 28 degrees F. Probably
not over 100 pots to an acre would be needed at most. Double the number
of pots should be placed around the outside row of the orchard to afford
the necessary protection.

The gravity of oil best suited for orchard heating is between 20 and 25
degrees Beaumé. It is essential that it be as free from impurities, such
as sulphur, as possible. During the spring of 1917, orchard heating was
done very extensively in some districts of the state while the trees
were approaching full bloom. As the season progressed it became apparent
that some serious injury had been done by the heating, for the bulk of
the blossoms fell off and the leaves turned yellow in streaks as if
burned by an acid. The appearance was exactly as if the particles of
soot settling on the pistils of the flowers and on the young leaves had
absorbed sulphur dioxide gas (a product of oil combustion where sulphur
is contained in the oil) and that the dews uniting with it to form
sulphurous acid had done the damage. Had the heating been done later and
only after the trees had passed full bloom, it is possible that a much
heavier set of nuts might have been secured, since the small fruits,
where they had formed, seemed to have been uninjured, only the pistils
of the flowers having been affected, probably preventing pollination and
fertilization of the ovules.

The time of heating is therefore a very important point. Almond blossoms
become progressively more tender to frost as they advance in development.
With their petals on they are not nearly as tender as they are after the
petals have fallen. They reach their most tender stage after the calyx
shucks have fallen from the young expanding fruits before they are the
size of a pea. Ordinarily, orchard heating before the trees have passed
full bloom is a waste of time and material and is often injurious. The
most needed time is for a period of two or three weeks after the bulk of
the petals have fallen, unless temperatures below 28 or 29 degrees are
encountered before that time.


CROP HANDLING

_Harvesting._—The harvesting of the crop should be commenced as soon
as the hulls have opened to their fullest extent and no time should be
lost in completing the work. The nuts in the center of the tree are the
last ones to ripen and so may be used as indicators. If harvesting is
commenced early, the nuts will cling to the tree rather tenaciously and
knocking must be very vigorous in order to shake them loose. On the other
hand, if they are allowed to hang too long after ripening, a number of
difficulties may be encountered. They may be blown to the ground by light
winds and the cost of gathering be increased, as quite commonly occurs
with the Peerless, or the hulls may dry up and in doing so, close around
the nuts to a greater or less extent and add to the cost and difficulty
of hulling. This is most noticeable with the Nonpareil. Strong winds
will break off a great many of the nuts of any of the varieties, and
promptness is doubly essential where there is any likelihood of such
winds during the harvest season. Depredations by birds may cause serious
losses, especially with the soft and papershell varieties. Infestation by
worms may often be quite serious in the papershell varieties when they
are allowed to hang too long. In case of damp or foggy weather the shells
turn dark and sometimes commence to mildew, requiring heavier bleaching
to brighten them sufficiently for market demands. Rain stains can never
be removed entirely by bleaching.

[Illustration: Fig. 20.—Harvesting almonds by knocking onto sheets spread
on ground.]

The crop is gathered by knocking the ripened nuts and hulls with long
poles onto sheets spread on the ground under the trees. The knocking
should be done near the portions of the trees where the nuts are borne
and by striking a number of light, quick blows, rather than by a heavy
blow aimed to jar a large branch. This will avoid injury to the bark by
bruising and will accomplish the work in less time. The blows should
always be delivered squarely against the branch. A glancing blow will
tear the bark and break off a great many fruit spurs, thus reducing the
bearing surface for the next year. For this reason harvesters must be
watched closely all the time to insure the proper use of the poles. The
sheets, two in number, are spread under the trees so they will overlap
and catch all the nuts that fall (see figure 20). When sufficiently
loaded with nuts to make dragging the sheets from one tree to another
difficult, they are emptied into lug boxes and sent to the huller.

The character of the harvesting equipment may vary considerably,
depending on the acreage, character of trees and ground, time required,
capital available, and the personal wishes of the owner. Some growers
use heavy poles of pine, spruce or fir, while others prefer the lighter
bamboo poles. The heavy poles are from 1½ to 2 inches in diameter at the
base and from ¾ to 1 inch in diameter at the top. Experience has shown
that poles of this type over 20 feet in length become unwieldy, and not
only swing slowly but do more damage because of the greater difficulty of
control. Most growers prefer 16-foot poles with a few 20-foot ones for
use in the tops of the taller trees. Where the tops cannot be reached
with these, the men climb into the trees with shorter poles. The bamboo
poles used are about 24 feet long and because of their lightness can be
used with greater speed. Bamboo poles with short internodes should be
selected as they are less likely to break. Breakage may also be reduced
by storing the poles in a cool place where drying-out will not be
excessive.

The sheets used are made of duck ranging in weight from 7 to 12 ounces.
Sizes of single sheets range from 12 × 24 to 24 × 48 feet. Sheets need
not be much longer than the longest diameter of the tree. To prevent
mildew and rotting of the fabric in the sheets they should be boiled in
a solution of tannin before being used. The life of sheets thus treated
will be greatly lengthened.

A number of growers have provided special contrivances by which sheets
are mounted on sleds or wheels so they are not dragged on the ground. The
principal objection to such an arrangement is that the sled or wheeled
frame must be made in two sections, one for each side of the tree, thus
increasing the cost of the operation because the horses can be used for
nothing else while harvesting is in progress. On the other hand, by the
dragging process sheets will not last more than two or three seasons,
whereas by the sled or wagon method they will last from six to ten years
longer. The two wagons shown in figure 21, each 12 × 24 feet, cost
between $60 and $70, about 1914. The canvas portion is of 8-ounce duck.
By this method the knockers can gather ten lug boxes before emptying.
The work can be done much faster with wagons. With the sleds a sheet is
fastened lengthwise on the right-hand side of one and another on the
left-hand side of the other sled.

_Hulling._—After harvesting, the almonds, hulls and all are taken while
still moist, to the huller to separate them. If they become dry before
hulling they must be dipped in water or the shells will be broken. All
hulling was formerly done by hand, and this is still done where only
small lots are to be handled. The invention of machinery for this purpose
has reduced the cost of hulling from 60 to 80 per cent, for most outfits
separate the hulls from the nuts before they leave the machine. Some of
the hand hullers consist simply of the hulling portion of the large power
machines without the separating screens. These cost about one-sixth or
one-seventh as much as the large machines, and where a man has a small
acreage and is too far away to haul to a large huller, a hand machine
will greatly facilitate the work, even though the final separation must
be done by hand.

[Illustration: Fig. 21.—Portable almond sheets mounted on wheels as used
by N. J. Lund, Oakdale, California, 1916.]

There are three different kinds of hulling and separating machines now
in operation in California, all invented by California almond growers.
The first one made was the Read “Sure-Pop” almond huller. This is now
manufactured in three sizes by the Schmeiser Manufacturing Company,
Davis, California. The No. 3 huller does not have any separating device
and is generally best for orchards of less than ten acres. It may be
operated by hand or by a small engine or motor. The No. 2 hullers both
hull and separate and are operated only by power. They should pay in
orchards of ten acres or more. The No. 1 is the largest made and is for
use in large orchards of 100 acres or more.

The Beach huller is of more recent origin, having been in use only since
1895. It was invented by J. E. Beach of Fairoaks, California, and is
being manufactured by him. The two sizes of this machine are both power
outfits; they are doing satisfactory work at the present time.

The third huller is that made by C. U. Reams of Suisun. One of the first
machines made by him was in 1897, and is now in working order at the F.
O. Scarlett ranch, northeast of Suisun, and is doing satisfactory work.
Since the first invention, Reams has made a number of improvements both
in the method of hulling and of separating.

Many growers do not have sufficient tonnage to enable them to afford
a commercial huller, and yet hulling by hand is a slow and tedious
practice. C. E. Sedgwick, Manager of the Solano District of the Pacific
Gas and Electric Company, located at Dixon, California, conceived the
idea of using a centrifugal blower operated by a small electric motor
to do the hulling. His description of this outfit, quoted from “Pacific
Service Magazine,” April, 1916, page 393, after making two small
corrections given by Mr. Sedgwick, is as follows:

    The equipment consists of a No. 0 Sturtevant exhaust fan belted
    to a 1 h.p. motor. The nuts are fed into the suction side of
    the fan where they are picked up by the runner, hurled against
    the casing of the fan and blown out of the discharge into a box.

    The motor consumes three-tenths kilowatts when almonds are
    fed into the fan at the rate of a lug box every minutes and
    one-half, so that the power cost, even at the 8-cent lighting
    rate, is only 2.4 cents per hour. The fan costs about $20,
    while the regular commercial hullers run as high as $750.

Further inquiry from Mr. Sedgwick developed the fact that this huller has
operated for three seasons on a 20-acre almond orchard. Peerless, Drake
and I.X.L. almonds were all hulled successfully. Nonpareils have not
as yet been tried. The speed most commonly used was about 1200 r.p.m.,
though it varied somewhat with the different varieties. He believes that
a larger size would do better work.

The efficiency of any of the above hullers depends largely upon the speed
of the machine and upon the condition of the almonds in the hulls. If
the machine runs too fast the almonds will be broken and injured, and if
it runs too slowly many of the almonds are not hulled. If the almonds
are allowed to hang on the trees too long, or if allowed to lie around
too long after being harvested, the hulls become dry and leathery and
the difficulty of hulling is greatly increased. Dipping in water in such
cases may help to overcome this difficulty to a limited extent.

The papershell varieties, notably the Nonpareil, are much more difficult
to hull without breaking the shells than are the harder shelled
varieties. The Nonpareil hull has a tendency to close around the nut on
drying, making hulling under such circumstances very difficult.

Often when the moisture supply in the soil is exhausted before the nuts
are ripe, or where the loss of leaf surface due to mites is serious
prior to ripening, the hulls open only slightly or not at all, but dry
onto the shell of the nut. Such “sticktights” can only be disposed of
profitably by allowing them to thoroughly dry, when they are cracked and
sold as kernels.

After the hulling operation all almonds must be gone over by hand to
remove pieces of hulls and inferior or gummy nuts. Where canvas drapers
are not available for sorting directly from the huller, the nuts are
piled in hoppers and sorted on benches beneath them.

_Drying._—Immediately following the sorting, the nuts are spread on trays
and thoroughly dried in the sun. In the interior valleys during the hot,
dry weather the nuts will sometimes dry so quickly that by the time the
sorting from hoppers is completed the nuts are sufficiently dry to be
bleached. The grower must be certain, however, that such is the case
before any bleaching is done, or before the almonds are delivered to the
warehouses for bleaching. The nuts are sufficiently dry when the kernels
will break without bending. Quick drying is essential to prevent the
excessive darkening of the shell.

_Bleaching._—When thoroughly dry the nuts are ready for bleaching. The
shells are first moistened by spraying with water or subjecting them to
low-pressure steam for 10 to 20 minutes. The shells are then subjected
to the fumes of burning sulphur for 10 to 30 minutes. The sulphur fumes
are absorbed by the moisture on the shells, which are bleached to a
bright yellow color. After bleaching the nuts are exposed to the air for
a few moments to allow them to dry. The market demands a nut that has
been sufficiently bleached to give it a bright, clean, yellow color.
An over-bleached almond is equally objectionable because of its pale,
sickly, yellow or whitish color. Over-steaming or sulphuring permits
excessive penetration of the sulphur fumes, with the resulting danger
of absorption by the kernel. While this may not be noticeable in the
flavor, it will eventually result in premature deterioration in the form
of rancidity. Unbleached almonds remain edible much longer than bleached
almonds in nearly every case. Ordinarily one to three pounds of the best
flowers of sulphur is required to bleach a ton of almonds. Lump sulphur
is not satisfactory.

_Sacking._—During the preliminary handling of almonds ordinary grain
sacks are commonly used. After bleaching, in which condition they are
ready for market, they are put in standard almond bags, measuring 20 × 40
inches and weighing 1¼ pounds. The weight of a bag of almonds will vary,
depending not only on the variety but also on the year in which the crop
was grown and the locality in which it was produced. For selling purposes
the California Almond Growers’ Exchange estimates weights of different
varieties to be as follows: Nonpareil about 85 pounds to the bag; I.X.L.
about 80 pounds; Ne Plus Ultra, 75 pounds; Drake, 90 to 100 pounds;
Languedoc, 100 pounds; and hardshell almonds, 100 to 120 pounds.

_Shelling._—Within the past two years the shelling of almonds has taken a
prominent place in the consideration of the men charged with the disposal
of the almond crop. The increasing popularity of shelled almonds, and
the limited market for unshelled almonds, makes the production of more
shelled almonds imperative in view of the prospects of greatly increased
production in the next few years. A small proportion of the shelled
almonds marketed are those accidentally shelled during the hulling
process. This probably averages less than 30 pounds per ton of almonds
hulled in ordinary years.

The varieties most commonly shelled are the papershells. They are much
more easily shelled without breaking the kernels than are the harder
shelled varieties and, in addition, are worth more for shelling because
of the high percentage of kernel compared to shell.

_Grading._—Grading almonds for size is not done at present but probably
will be within the next few years. Grading for quality is done regularly
by testing an entire lot rather than attempting to separate inferior
nuts. The standard grade consists of all lots having the required
percentage of good kernels, free from worms or gummy nuts. This
requirement varies between 90 and 95 per cent, depending on the condition
of the crop as a whole and on the market conditions. The standard grade
of a given variety sells on guarantee that it shall be up to advertised
standard. All lots which cannot pass this are sold on sample, and
therefore, on their own individual merits.


MARKETING

The marketing of the California almond crop is at present on a firmer
basis than at any time in the past. Previous to 1910 there was little or
no coöperation among growers and the buyers had everything their own way.
In May of that year, however, Mr. J. P. Dargitz, an almond grower near
Acampo, California, successfully organized the California Almond Growers’
Exchange, consisting of nine local associations with a total membership
of 230 growers. The Exchange started business with $1000 borrowed
capital, personally guaranteed by the directors. On June 1, 1918, there
were 22 sub-associations representing about 2000 growers, controlling
about three-fourths of the crop. The Exchange now is not only out of debt
but owns investments aggregating $100,000 in value, including warehouses,
a central shelling plant and other property. At the same time, the
growers have been receiving about 50 per cent more for their almonds
than before the Exchange was organized.

The success of the Exchange, with the consequent higher prices to the
grower, has resulted in a large increase in the acreage of almonds in
California. This increase is making it necessary to develop new markets
to absorb the greater tonnage, and this can only be done effectively or
satisfactorily by coöperative effort.

Heretofore, California almonds have been marketed chiefly in the shell.
A small proportion has been cracked annually to supply western brokers
and confectioners, and practically all of these have been sold west of
the Rocky Mountains. Only the whole nuts have been shipped to the eastern
markets.

The European crops are sent to the United States largely as kernels and
have had a practical monopoly of the shelled almond business east of
the Rockies. The Tarragonas and Valencias shipped to America come into
direct competition with the I.X.L., Drake, Languedoc and other California
almonds, all of which are unshelled for the eastern markets. The imports
of unshelled almonds average about the same as the California production.
The Jordan, Princess and other varieties, however, come in shelled,
constituting the bulk of the importations. The Jordan, because of its
superior quality, is in a class by itself and does not compete at present
with the California product. The Princess and other almonds of that
type are much the same as the California shelling varieties and will be
serious competitors when sold in the same markets.[4]

_Storing._—Almonds awaiting removal or sale will become rancid if stored
in warm or damp places. If the almonds have been properly cared for
during the handling process to prevent worm infection, and if the nuts
have been thoroughly cured, they will keep satisfactorily for a year or
more. The ideal condition is to keep them stored in a uniformly cool, dry
storage place with ample ventilation.


YIELDS

The yield of almonds in different years and in different orchards is
probably more variable than that of any other of the common orchard
fruits. The fluctuations from year to year are largely due to climatic
conditions, while the variations in different orchards are largely due
to variety, care given the trees throughout their life, the character of
the soil, and location with relation to local frost conditions.

Almonds first commence bearing at from two to four years of age; the
first crop ranging from one or two nuts up to a hatful or possibly
more. The trees will first commence to bear a crop which it will pay
to harvest, at from three to five years of age. Ordinarily, it will be
nearer the latter, depending upon the type of soil in which the trees are
growing and the moisture conditions surrounding them. On the hill lands
the trees begin to mature much earlier than in the rich bottom lands and
consequently come into bearing earlier. It must be borne in mind that a
crop which it will pay to harvest does not necessarily pay for the cost
of orchard maintenance. A crop is not considered a paying crop until it
pays for the cost of maintenance as well as harvesting and handling.
Almond orchards, as a rule, reach this point at from five to seven
years of age. From this time on the trees should continue to increase
in production from year to year, allowing for failures due to frost and
other unfavorable conditions, until they are from 12 to 20 years old.
Under the common methods of care that most orchards receive, the trees
commence to decrease in their production at from 25 to 30 years, although
in some cases it will be even sooner than that. On the other hand, well
cared-for orchards will continue their maximum production even longer.
The age at which an orchard will no longer pay will range from 30 years
upward. The top limit is still unknown.

Investigations carried on during 1913-1914[5] brought out the following
facts: The average production of almonds in California is between 700
and 800 pounds per acre; if care is exercised in the selection of a
proper location for an orchard and if good judgment is used in managing
it, 1000 pounds per acre would be a safe estimate for business purposes;
in many years competent men might be expected to obtain 1500 pounds per
acre, but this could not be expected to hold for a ten-year average. The
possibilities are shown by the crop from one acre on the University Farm,
at Davis, California, of ten-year-old trees which amounted to nearly 2800
pounds in 1917.


COST OF PRODUCTION

The cost of producing almonds involves a number of variable factors,
including overhead charges, such as the cost of the land, equipment,
taxes, insurance and depreciation; and also the cost of maintenance
and handling. Maintenance includes such costs as pruning, plowing,
cultivating, spraying and irrigation. Handling includes harvesting,
hulling, hauling, and warehousing. Tabulations of estimates in tables II
to VIII are based on information collected during the years 1913 to 1916,
inclusive, from a large number of growers in practically all the almond
districts of the state, and represent as accurately as possible with the
data at hand the average costs which actually exist throughout California.

_Cost of the Land._—The estimates given in table II are to be taken as
only partially indicative of conditions which actually exist in the
various districts mentioned. These figures do not give the entire range
of prices but indicate some of the more common values placed upon the
land.


TABLE II

VALUE OF ALMOND LAND IN CALIFORNIA

                                                          Land in bearing
                   District—               Bare land          orchard

    Best Sacramento Valley land             $200-$400        $400-$600
    Other good interior valley lands         150- 300         400- 500
    Sacramento Valley, foothill sections      75- 150         200- 400
    Contra Costa County                      100- 300         250- 500
    Santa Clara and San Benito counties      300- 600         500- 800
    Paso Robles district                      50- 150         ........
    Banning district                         400- 800         600-1000
                                            ---------         --------
       Averages for California                 $250             $500

_Equipment._—It has been found impossible to gather accurate figures upon
cost of equipment in almond orchards, and especially so in view of the
present abnormal economic conditions, but the list given in table III
will give an idea of the equipment required. In addition, there will be
other small items the grower will need which are not mentioned here.


TABLE III

ALMOND ORCHARD EQUIPMENT

    Plows
    Harrows (spike-tooth and spring-tooth)
    Disc Cultivator
    Weed cutter
    Clod masher
    Roller
    Hoes, shovels, etc.
    Pruning tools
    Brush burner
    Spray outfit
    Wagon
    Barns, sheds and other buildings
    Harvesting equipment:
      Almond sheets
      Poles
      Lug boxes
      Hulling machine
      Sorting tables and bins
      Drying trays
    Sacks for transportation to warehouse
    Orchard heating equipment ($25-$30 per acre)
    Horses or tractors
    Harness

_Average Overhead Charges._—Table IV shows the average overhead charges
for almond orchards. Interest and depreciation on buildings are not
included because of the great variation in their character, so that an
extra charge must be figured on these items by the individual grower.


TABLE IV

AVERAGE OVERHEAD CHARGES PER ACRE

    Taxes and insurance                   $4.00
    Interest                              30.00
    Depreciation on working equipment      4.00
                                         ------
       Total                             $38.00

_Cost of Production._—Table V shows the average cost of production
for bearing orchards of varieties in all districts, based on personal
observation and cost records from a large number of orchards mentioned
previously. Wherever cost is dependent upon tonnage the average yield of
700 pounds per acre is used as the basis for computation. Depreciation
on buildings and trees, time spent by teams in idleness, feed consumed
during such times and other minor items are too variable to safely
estimate, but must be considered.


TABLE V

AVERAGE COST OF PRODUCTION OF ALL BEARING ORCHARDS IN CALIFORNIA

                                                      Per acre
    Maintenance:
      Pruning                                            $3.00
      Plowing                                             2.75
      Harrowing                                            .75
      Cultivation and weed cutting                        3.00
      Spraying                                            3.00
      Irrigation                                          2.00
    Handling:
      Harvesting, hulling, etc.                          20.00
      Warehousing (including bleaching), @ ¼c per lb.     1.75
    Miscellaneous expense for maintenance and handling    2.00  $38.25
                                                        ------
    Overhead charges                                             38.00
                                                                ------
          Total cost per acre                                   $76.25
    Cost per pound for maintenance and handling                 $0.055
    Cost per pound for overhead charges                          0.054
                                                                ------
          Total cost per pound                                  $0.109

_Returns._—Prices paid to growers have fluctuated considerably, due to
the great variation in both the California and European crops from year
to year. Table VI shows the average prices per pound paid to the growers
for the four principal varieties marketed through the Exchange since its
organization.


TABLE VI

NET PRICES REALIZED BY THE EXCHANGE MEMBERS FOR DIFFERENT VARIETIES FOR
THE YEARS 1910 TO 1916, INCLUSIVE, IN CENTS PER POUND

                                   Ne Plus             Crop
    Year    Nonpareil    I.X.L.     Ultra    Drake     tons

    1910      14.00      13.00     12.00     10.00    3,500
    1911      16.50      15.50     14.50     12.00    1,450
    1912      13.25      12.25     11.25      9.50    3,000
    1913      17.25      16.25     15.25     13.25    1,100
    1914      18.00      15.00     14.50     11.50    2,250
    1915      13.00      12.00     11.00      9.25    3,500
    1916      17.25      14.75     13.75     13.00    3,400
              -----      -----     -----     -----    -------
    Average   15.61      14.11     13.18     11.22    2,571.4

Table VII shows the average price per pound paid to the growers for
all almonds (unshelled) regardless of quality and variety, based upon
the entire crop handled by the Exchange during the years 1910 to 1916,
inclusive. From these figures the average return per pound for all
varieties for seven years based on the crop tonnage for each year, 1910
to 1916, inclusive, has been found to be 13.09 cents per pound.


TABLE VII

AVERAGE PRICES PER POUND PAID GROWERS FOR ALL UNSHELLED ALMONDS FOR THE
YEARS 1910 TO 1916, INCLUSIVE

               Price per pound,  California crop,
    Year            cents             tons

    1910            12.0             3,300
    1911            13.5             1,450
    1912            11.0             3,000
    1913            15.5             1,100
    1914            14.05            2,250
    1915            10.75            3,500
    1916            13.97            3,400
                    -----            -------
    Average         13.09            2,571.4

The relation of yields, returns and profits from the growers’ standpoint
is one which every person must consider before entering the business. In
view of the extravagant claims which have been made as to the enormous
profits realized by the average grower, the figures in tables II to VIII
have been worked out and presented here. The summation of the relation
of yields, returns and cost of production to the profits for the average
grower of almonds is shown in table VIII.


TABLE VIII

RELATION OF AVERAGE YIELDS, COSTS AND RETURNS, TO PROFITS

    Average yield per acre               700 pounds
    Average returns to grower per acre                 $97.30
    Average cost of production per acre                 76.25
                                                       ------
    Average profit per acre                            $21.05


Depreciation on buildings and trees, and other unfigured costs, are too
variable to estimate, but they must come from these profits.


DISEASES

_Crown Gall._—Also commonly known as root-knot. This disease is one
of the most serious with which the grower has to contend. It is found
practically everywhere almonds are grown and either greatly reduces the
vitality of or kills the trees affected, depending upon the seriousness
of the attack.

The disease is caused by a bacterial organism, _Bacterium tumefaciens_,
that seems to be native to most California soils. It is characterized by
large swellings on the root crown or main roots just below the surface of
the ground, though lesser infections may sometimes be found also on the
smaller roots. When cut open, these knots appear spongy as if the bark
and wood were all mixed together in one mass. They are most serious when
spread over a large surface, either partially or completely girdling the
root or crown of the tree.

Control methods are of three kinds:

(1) Plant nothing but clean, healthy nursery trees, free from all trace
of galls. In planting these trees be careful to trim off all broken or
injured roots, leaving nothing but smooth clean cuts at the ends of the
roots which will heal over readily with the minimum opportunity for
infection.

(2) Galls on orchard trees may be cut out to clean, healthy wood with a
sharp knife or gouge chisel. The wound should be thoroughly disinfected
with a strong copper-sulphate or corrosive-sublimate solution, and
painted with a protective covering such as paint or melted asphaltum,
or it may be covered directly with Bordeaux paste and then the earth
returned to its place over the roots.

(3) A method used with apparent success is to bore a one-inch hole about
two-third of the way through each gall, as soon as the trees have become
dormant in the fall. Then fill each hole with a concentrated solution of
copper sulphate and plug the opening. By spring, when growth is ready
to start, the gall may be knocked off with a hammer. In most cases the
gall is so thoroughly permeated by the solution that the infection is
completely killed and further gall growth ceases in that place, unless
later infection occurs.

The use of resistant stocks has been suggested as a means of avoiding
infection, but no such stock suitable for the almond has yet been proved
to be sufficiently resistant under average conditions to be safely
recommended. The greatest hopes for future success in combating this
disease, however, lie along this line.

_Oak Fungus._—This is one of the most difficult diseases to control
because it works and spreads beneath the surface of the ground in the
roots of trees. In some sections of the state it is very serious in many
orchards.

The disease is often known as root-rot, being caused by a fungus
_Armillaria mellea_, commonly called “toadstool” fungus. It is known as
Oak fungus because the disease is most commonly found in spots where old
oak trees have stood. Where orchards have been planted on such land,
spots appear in which the trees gradually die, the disease spreading from
tree to tree, in ever-widening circles, involving ordinarily about one
row of trees each year. During the winter, clusters of toadstools may be
seen at the base of the affected trees. The fungus lives over in the old
oak roots for many years and, as the orchard becomes well established,
the fungus spreads to the almond roots. If not checked the spot will
eventually involve the entire orchard and prevent further growth of
almonds on such land for many years.

Control is very difficult but may be secured by digging a deep trench
around the affected area and preventing the infection from passing beyond
through the roots. The spread of the disease may sometimes be held in
check by grubbing out a row or two of healthy trees outside the affected
area and taking care that all of the large roots are removed to a depth
of several feet. Carbon bisulphide has been suggested for killing the
fungus, but the cost is prohibitive except in small spots just starting.

There are no resistant stocks known at present upon which the almond can
be worked. The fig, pear or black walnut might safely replace the almond
in such spots.

_Shot-hole Fungus._—There are three different fungi that produce the
shot-hole effect on the leaves of the almond, thus giving rise to the
name.

(1) _Coryneum beyerinikii_, or peach blight, is the most common form. It
is not as serious on the wood of the almond as it is on the peach, but
in seasons of damp spring weather it does much damage to the blossoms,
fruits and leaves. Affected blossoms are killed outright, the entire
blossoms turning brown and dropping much as if killed by frost. The young
fruit becomes spotted by the fungus and this causes malformation, gumming
and shriveling of the nuts, varying considerably with the severity of
the attack. On the leaves many small dead spots appear, the dead tissue
soon falling out and giving the shot-hole effect. Where the twigs are
affected, small dead spots appear during the winter, most often at the
buds. This causes the death of the buds and often the ends of the twigs.
During the spring, after growth starts, considerable gumming occurs from
these spots.

Effective control can only be secured by two sprays—Bordeaux mixture in
the fall, as soon as the tree becomes dormant, and either Bordeaux or
lime-sulphur solution (winter strength) just before the buds open in the
spring. Both fall and spring sprays must be thoroughly applied to be
effective.

(2) _Cercospora circumscissa_ is another fungus causing much the same
effect as the Coryneum. It is difficult for an untrained person to
distinguish between them. The same sprays used for Coryneum are effective
in controlling this, though if this form alone is present the Bordeaux
mixture or lime-sulphur spray in the spring should be sufficient.

(3) _Gloeosporium amygdalinum_, while apparently uncommon in this state,
has been found to exist in some places. Further work must be done on this
to determine its behavior and the most satisfactory methods of control,
but it is believed that the control measures mentioned for the other
forms of “shot-hole” will also be applicable to this.

_Prune Rust_ (_Puccinia Pruni_).—This fungus is worst in the southern
coast sections where almonds are not extensively grown. It is not
serious on thrifty trees well supplied with moisture. The disease is
characterized by reddish pustules on the under-sides of the leaves,
appearing generally about July or August and causing a premature
yellowing and dropping of the leaves.

Ordinarily the only treatment needed is to supply the necessary moisture
in the soil to keep the trees healthy and vigorous.

_Heart Rot._—This is one of the most insidious of tree diseases, for it
works inside beneath an apparently healthy exterior until the decay has
progressed so far that the tree commences to break down, and then it is
too late for remedial measures. The almond is not as susceptible to this
as most other kinds of orchard trees, but where large wounds have been
exposed to the weather, infection may take place readily, and after it is
once well started it continues at a comparatively rapid rate. Decay is
caused in most cases by one or more of about a dozen different fungi, of
which the oyster-shell fungus is by far the most common.

Control consists in taking care to leave no open wounds exposed to the
air to dry and crack, thus permitting the entrance of decay organisms.
Much of this can be avoided by care in pruning the young tree so that the
removal of the large limbs will not be necessary later on. Where such
wounds must be made, measures should be taken to prevent infection. This
can best be done by making smooth, clean cuts close to the part from
which the branch to be removed emanates, leaving no stub. Stubs dry out
and crack more quickly and require very much longer to heal over, if this
is possible at all. Further, all such wounds which will not heal over
the first season should be covered with some good disinfectant, such as
corrosive sublimate, one part to one thousand parts of water, and then
painted over with some elastic coating, such as “Flotine” or asphaltum,
grade D, applied with a brush. The entire wound must be covered or the
work is largely wasted.

_Die-back._—This is serious in many orchards where moisture is
insufficient to carry the trees through the growing season, and the
trees show considerable dying-back of the branches. Unfavorable soil
conditions, such as hardpan, gravel or sand may be the direct cause of
such moisture shortage. Lack of soil fertility is also a common cause.
Control measures consist in remedying the defective conditions and where
this cannot be done economically it is better to abandon further attempts
at almond culture on such land.

_Sour-sap._—This is one of the so-called “physiological diseases” and is
quite common with the almond. It is most frequently found where trees
are planted in heavy or poorly drained soils. The inability of the
almond to endure standing water around its roots for any length of time
and particularly so after growth commences in the spring, renders it
especially liable to sour-sap when planted in soils where excess water
from the late winter and spring rains cannot be readily drained away. The
direct cause of the trouble is sudden changes in weather from warm to
cold after growth commences, which checks the flow of sap very suddenly,
causing stagnation, cracking of the bark and then fermentation. With an
unusually strong flow of sap in trees in wet soils, such climatic changes
cause unusually severe disturbances in the normal functioning of the
trees.

The affected trees ordinarily show the disease first in the spring when
gum may be seen oozing from the bark of the trunk or main branches, and
sometimes even from the smaller branches. Small or large branches may
die, and in severe cases the tree may die soon after having commenced to
leaf out strongly. On cutting through the bark to the wood and peeling
back, a strong sour odor is noticeable. The cambium layer appears
brownish or reddish in color and often masses of gum may be found between
the bark and the wood. Mild cases may not be serious enough to show on
the outside of the tree and only portions of the cambium layer may die.
The sudden dropping of the blossoms or young fruit may in some instances
be attributable to sour-sap.

All affected parts on smaller branches should be cut back to healthy
wood, while on the main branches or trunk, where only a small portion or
one side is affected, it is best to clean out the dead bark and paint the
bared wood with a protective covering until new bark can cover the spot.
At the same time every effort should be made to remedy the soil-moisture
conditions which were largely responsible for the trouble in the first
place.

_Fruit-drop._—The same conditions which cause sour-sap may cause fruit
drop. It may be caused by lack of pollination due to improper mixing of
varieties or to rain during blossoming. Frost may also produce the same
thing by killing the germ in the young fruit. In such cases, the fruit
may remain on the tree for one or two weeks after the injury occurs
before falling, and in some cases, may even appear to continue its
development for a short while.


INSECT PESTS

_Mites._—Commonly called red spiders. There are two kinds of mites that
do much damage in almond orchards, the brown or almond mite and the
yellow or two-spotted mite. Both are common in all parts of the state and
are the worst pests the almond grower must regularly face.

The brown mite (_Bryobia pratensis_) is the larger of the two, is dark
red or brown in adult stage, has very long front legs, and a flattened
back. It does not spin any web and works on the green bark of the small
twigs as well as on the leaves, sucking the plant juices from beneath
the bark. It causes a mottling of the leaves which eventually fall,
although not as readily or in such large numbers as when attacked by the
yellow mite. The injury to the tree is equally as great because of the
serious drain on the vitality as a whole and because it commences work
earlier in the season. This mite may spend its entire life on the tree;
the very small, round, red eggs being laid largely on the under-side of
the branches and in cracks and crevices in the bark and twigs. These
remain on the tree throughout the winter and hatch early in the spring
soon after the trees have their leaves half developed, leaving the white
egg-shells in place. Most of their work is done in the spring and early
summer.

[Illustration: Fig. 22.—Nonpareil almonds. Branch on left free from Red
Spider and holding its full supply of leaves in green, healthy condition;
branch on right defoliated by Yellow Mite. Note premature ripening of
nuts on defoliated branch.]

[Illustration: Fig. 23.—Forty-three-year-old Languedoc almonds on peach
root, near Davis. This orchard has not been thoroughly cultivated or
irrigated. Mites have largely defoliated the trees. See contrast in Fig.
24.]

The brown mite may be controlled satisfactorily by means of a dormant
spray of lime-sulphur solution, 1 gallon to 10 gallons of water, applied
just before the buds open in the spring. Crude oil emulsion as a dormant
spray is also effective, if thoroughly applied over the entire tree under
high pressure. This also applies to applications of the lime-sulphur
spray.

During the growing season a milder material must be used. Dry dust
sulphur, using only the very finest grade of “flowers of sulphur,” is
often very effective, provided weather conditions are satisfactory, but
generally this must be applied a number of times if best results are to
be obtained. The work is done by blowing the sulphur dust into the tree
with blowers in the early morning when there is little or no wind.

A more satisfactory method is the use of “Atomic sulphur” or other
sulphur pastes or similar material. “Atomic sulphur” is a prepared spray
whose value consists in the fact that the sulphur is held in suspension
in water so that it may be applied as a liquid spray. By this method the
material may be more effectively and thoroughly applied. “Atomic sulphur”
is applied at the rate of 10 pounds to 100 gallons of water.

[Illustration: Fig. 24.—Forty-three-year-old Languedoc almonds on
peach root, near Davis. This orchard has been irrigated and thoroughly
cultivated, and mites have not defoliated the trees. Note contrast in
Fig. 23.]

The use of lime-sulphur, the commercial strength of 33 to 34 degrees
Beaumé being diluted 1 part to 35 parts water, is another effective
method. For such use a flour paste may be added at the rate of 4 gallons
to each 100 gallons of the spray mixture to act as a spreader. This paste
is made by cooking one pound of flour with enough water to make one
gallon of the mixture.

The yellow mite (_Tetranychus telarius_) is much smaller than the brown
mite and is of a pale yellow color with occasionally a reddish tinge and
sometimes with two darker spots on either side of the body. Unlike the
brown mite, the winter is spent in concealment somewhere, presumably
off the tree. During the warm days of early summer, generally in June,
the mite makes its appearance on the trees, spinning a fine web on the
leaves, generally on the upper surface, and then works under this web.
The mite sucks the plant juices from the leaves giving them a yellowish
mottled appearance. These leaves soon die and drop to the ground. In
serious infestations the trees are often almost completely defoliated by
the end of August. (See figure 22.)

The use of dormant sprays is not effective for controlling the yellow
mite, but the summer sprays mentioned above are all satisfactory, and for
best results, must be applied under high pressure, preferably 200 pounds
or more.

The mites are much easier controlled where a comparatively high
percentage of moisture is kept in the soil by frequent cultivations, or,
if necessary, by irrigation (figures 23 and 24).

_Peach Twig Borer_ (_Anarsia lineatella_).—In the larval stage these
borers work on the young buds and shoots in the early spring. They
are especially troublesome in newly planted orchard trees when a
comparatively small number may kill most of the new shoots which are
needed to make the desired framework of the tree. In some years they may
be serious in large trees also. Dormant spray of lime-sulphur applied
under high pressure just as the buds are opening in the spring will
control the borers very effectively. This same spray may be used to
control the brown mite, thereby accomplishing double control.

_California Peach Borer_ (_Ægeria opalescens_).—The larvae are serious in
many parts of the state where they burrow just under the bark near the
surface of the ground. They may be detected by the small bits of frass
and gum at the entrance of their burrows. If allowed to continue, they
will eventually girdle the tree.

The surest means of control is to dig out the worms with a knife or kill
them with a wire probe. This work should be done systematically once
or twice every year and very thoroughly if it is to be effective. The
application of hot “Flotine” or asphaltum, grade D, after the worms are
killed should help considerably to prevent the entrance of the larvae. To
be effective it must be applied at least twice a year on young trees and
probably the same on old trees.

_Thrips._—These are most serious on the almond leaves, their attacks
being serious enough to cause considerable defoliation in late spring or
early summer. They may be controlled by spraying with lime-sulphur, 1
to 30, to which has been added black-leaf 40 (40 per cent nicotine) at
the rate of 1 part to 1500 parts of water or other spray-mixture. It is
possible that other than the pear thrips have been doing damage, but the
same spray as described above should be effective against all.

_Grasshopper._—Grasshoppers have been serious in orchards in outlying
foothill districts in some years, and especially so in young orchards
where it has been almost impossible to get trees started properly. In
such locations special means must be employed on a large scale to protect
orchards from their devastations, of which poisoned bait and hopper
dozers are the most effective.

[Illustration: Fig. 25.—Almonds infested with larvae of Indian Meal Moth
(_Plodia interpunctella_).]

Indian Meal Moth (_Plodia interpunctella_).—The larva of this moth feeds
on the kernels of the harvested almonds when they are stored. Infestation
usually takes place in storerooms or warehouses in which the nuts have
been placed for a time. The warehouses become infested from old grain
bags which have been kept there at one time or another. So far as known,
infestation does not take place in the field. The larvae will continue to
work in the stored almonds for a long time, doing a very great amount of
damage (fig. 25). They may be controlled by thoroughly cleaning out the
corners of the warehouse and thoroughly disinfecting. The nuts should be
disinfected with carbon bisulphide (explosive when in the form of a gas
mixed with air), or other means used to control insects in grain.[6]
Prevention is far easier than the cure in this case.

Scale, aphis, diabrotica and other insects are sometimes found on the
trees, but are generally not sufficiently troublesome to require special
attention. Most of them are held in check by the control measures used
for the more serious pests.


OTHER PESTS

_Gophers._—These often do great damage to the trees by girdling them
just below the surface of the ground, or if they do not actually girdle
the trees, they cut them enough to devitalize them and, in addition, the
wounds made by their gnawings frequently become infected with crown-gall
organisms. The only safe means of control is the constant use of traps
supplemented by poisoned bait.

_Squirrels._—Squirrels are very troublesome, as they harvest a large
amount of almonds before they are sufficiently ripe to be harvested by
the grower. The use of poisoned grain or “gas,” if used over a large area
of surrounding territory, will prevent serious depredations.

_Birds._—Birds also carry off large amounts of almonds if the orchards
are near open country or hills, especially if wooded. Crows, bluejays,
blackbirds, yellow-hammers, robins and other similar birds are the worst
offenders. Sometimes linnets eat off large numbers of fruit buds in the
spring in a few of the newer sections where plantings are scattered.
Sap-suckers have been known to girdle entire trees or large branches by
cutting large numbers of holes in a series of lines close together around
the trunk or limbs.

_Morning-glory._—This is probably the worst of the weeds in almond
orchards, and is the hardest to control. Sheep and chickens may be used
with excellent results, provided care is taken to see that the sheep are
not allowed to go hungry, for then they will bark the trunks of the trees
very quickly. An excellent plan is to arrange gates so that the sheep
must go through the orchard from pasture to get water. In passing back
and forth they will forage over the entire orchard and dig up all the
morning-glory in sight. Chickens are fond of the succulent new shoots,
and will keep them below the ground until the underground stems and roots
weaken and die. Cultivation throughout the growing season, often enough
to prevent the morning-glory from developing any leaves for a whole year
at least, and longer if necessary, will starve the plants to death.


VARIETIES

The problem of selecting varieties of almonds for planting in California
is to choose the ones that are most marketable and at the same time to
secure best results in cross-pollination. At the present time there are
comparatively few varieties of almonds which have won and retained their
popularity with the grower and the trade. There are a number of reasons
for this condition. The cultural, climatic and soil conditions under
which the almond thrives are much more limited than for most of the
common deciduous fruits; the area of production in America is limited
largely to California; the industry is comparatively new, and in general,
there is not the great varietal variation in season, appearance, texture,
flavor and behavior that is found in the apple, peach, pear and similar
fruits. The comparatively rapid deterioration of fleshy fruits after
ripening makes a succession of varieties desirable to extend the period
of consumption. With almonds, the season of all varieties extends from
one harvest to the next, if properly handled. Growers are, therefore,
recommended to plant only standard, marketable varieties as far as
possible.

Early ripening varieties must be chosen. The crop must be in the hands of
the trade early, for the bulk of it is used in the holiday trade. This
is especially true with unshelled almonds. Early almonds only can be
harvested and sold before the bulk of the European shipments arrive.

The actual time of ripening of the different varieties is variable from
season to season, and in different sections or even different orchards
in the same season. Generally, harvesting commences early in August and
closes about the middle of October. The approximate order of ripening of
the better known varieties is shown in table IX.


TABLE IX

APPROXIMATE ORDER OF RIPENING OF VARIETIES OF ALMONDS

    1. Nonpareil
    2. I.X.L.
       Jordan
    3. Ne Plus Ultra
    4. Peerless
       Princess
       California
       King
       Silver
    5. Golden State
    6. Lewelling
    7. Drake
    8. Languedoc
       Texas

Many new varieties have been originated in California but most of them
have fallen into disfavor in a short time. In fact, it is impossible to
locate even single trees of some varieties which were formerly well
known. From time to time, however, worthy varieties have been introduced
and have succeeded in making a permanent place for themselves through
their ability to fill a demand that before had been but partially or
poorly supplied.

In view of the changing market situation for California almonds, due to
the rapidly increasing acreage and the very limited demand for unshelled
almonds, it is safe to predict that the only new varieties which will
be of value in the future will be those that are primarily of superior
quality for shelling purposes. Yield must take second place.

Well known varieties are not only in heavier demand in the principal
markets, but they invariably bring much better prices than the newer
varieties. In some years, when the domestic crop of a given variety is
light and the demand good, it is possible to unload poorer or less known
varieties at fairly good prices. More often, however, they are a drag on
the market.

Owing to the increasing consumption of shelled almonds and the
probability of a still greater increase in the future, growers should
arrange future plantings with a view to supplying the best shelling
varieties. At the present time, the best shelling varieties are not
ordinarily the heaviest producers. With a limited production they may not
even bring as large returns as the poorer but heavier yielding varieties.
As the production increases, which it is doing very rapidly, the relative
value of the best shelling varieties will increase in proportion and they
may be sold at good prices when it will be impossible to move a heavy
tonnage of a poor variety at a profitable price.

Although the future almond markets will no doubt use shelled almonds very
largely, there will always be a limited demand for unshelled almonds
for use in the holiday trade and for home table use. Unshelled almonds
to be acceptable for such purposes must be large, attractive nuts with
light-colored, clean-looking shells, soft enough to be broken with the
hands. The kernels must be well filled and free from gum. The I.X.L. is
the most popular and highest-priced nut for this purpose. The Ne Plus
Ultra ranks next because of its attractive outside appearance and shape;
one of the principal objections to it being its tendency to have gummy
kernels. The Drake is another variety in demand for this purpose. It
is moderately large, plump and well filled with a good quality kernel,
and while not as attractive as the I.X.L. or Ne Plus Ultra, it is
popular with the medium-priced trade. A certain class of trade prefers
the Nonpareil for such use, and it appears to be growing in popularity
because of the attractive kernel and the ease with which shelling by hand
is accomplished.

The confectioners, on the other hand, care nothing for shell. They want
a medium or large sized kernel, uniform in shape, and plump; one that
can be coated smoothly or evenly with candy. For blanching and salting
purposes, the kernels must be large and smooth. The best California
variety for this purpose is the Nonpareil. It is also the best nut for
table use when sold shelled. As a rule, the papershell varieties are the
best for shelling because of the large percentage of unbroken kernels
which may be obtained. The broken kernels and those obtained from
cheaper and less desirable varieties are used largely by the bakers and
almond-paste manufacturers.

The planting of large blocks of orchards to single varieties is not a
wise practice. Planting of several varieties will assist greatly in
lengthening the harvest season, and thus enable one to handle large
crops with fewer men and less equipment. For example, the four best
varieties—the Nonpareil, I.X.L., Ne Plus Ultra and Drake—ripen in the
order named; the Nonpareil ripening about two weeks before the I.X.L.,
the Ne Plus Ultra about a week after the I.X.L., and the Drake about
two weeks after the Ne Plus Ultra. Where there is danger of failure
of varieties to set fruit due to frost or improper pollination or
unfavorable weather conditions during, or soon after, blooming, the
grower is more likely to get a crop from some variety if several are
planted to secure a succession of bloom in the spring.

The principal reason for interplanting varieties is to secure adequate
cross-pollination. For this purpose the Ne Plus Ultra and Drake are
probably the best to use as pollenizers.

Other combinations, as indicated on page 6, may be made that will be
satisfactory, though care must be exercised to secure varieties that
blossom near enough together to be effective. Figure 26 shows the
effective blossoming period for fifteen varieties.

_Adaptation of Varieties._—The best marketable nuts are, as has been
suggested, few in number, and most of these do well in all of the
principal almond districts of California. Where the climatic and soil
condition are equally favorable there is no great variation in their
behavior, but owing to such differences it has been found that certain
varieties are better adapted to some districts than others.

The Nonpareil, the best variety known at the present time for California
conditions, bears more nearly uniform crops from year to year and shows
a wider range of adaptation than any of the other good commercial
varieties. It has proved itself to be satisfactory in every almond
district in the state. The Drake closely approaches the Nonpareil in this
respect. The I.X.L. and Ne Plus Ultra are the most variable in their
behavior. The blossoms of the two varieties seem to be more tender and
hence more liable to injury under unfavorable conditions; gumming is more
prevalent near the coast, and during harvest the slower ripening and
opening of the hulls in the more moist atmosphere in many of the coast
valleys causes excessive darkening and sometimes molding of the shell.
The Ne Plus Ultra does its best on comparatively high, well-drained
soils, adjacent to the larger streams in the Sacramento Valley, such as
the lands along the Sacramento River, Putah Creek, Cache Creek, etc.,
though it also grows and produces well in the Banning district and in
many of the foothill sections where conditions are favorable. The I.X.L.
does best on the foothills surrounding the Sacramento Valley, notable
on the west side. In the Banning district the Ne Plus Ultra seems to be
a better producer than the I.X.L. Varieties which ripen later than the
Drake should be avoided in the Banning district because of the liability
to damage from the frequent October rains.

There are a number of different varieties, such as the Eureka and Jordan,
which give promise of filling a limited place in the markets but which
have not yet been thoroughly tested throughout the state. The Eureka
is popular with confectioners because of the similarity in shape to
the Jordan. In limited quantities the demand is good. It is still a
question as to whether it would hold up in price if grown in very large
quantities. The Jordan nut is of excellent quality but in California
the trees are variable in vigor. In some cases the trees make unusually
large, vigorous growth while in others they are small and apparently
stunted. The cause of this has never been adequately determined. In
general, the Jordans do not bear sufficiently heavy crops to make them
pay at the prevailing low prices. The chief reasons for the low prices
are the extreme hardness of the shell and the absence of satisfactory
methods of shelling. The invention of a satisfactory machine for this
purpose would probably make it pay to plant Jordans in much larger
quantities.

[Illustration: Fig. 26.—Period of Effective Blossoming of
Almonds—University Farm—1917.]

Other varieties, such as the Texas, have been sufficiently tested to
show them to be well adapted to most districts, but they are not to be
recommended because of the difficulty experienced in marketing them at
a profit in large quantities. The Texas has been planted extensively
in California without sufficient justification. It was planted because
of its value as a pollenizer, its precocious and prolific bearing, and
its upright habit of growth. In small quantities it was sold in less
exacting markets as a Drake, but in larger quantities there has been a
good deal of objection to it on the part of the trade. As the bearing
trees become older and bear heavier crops, the nuts tend to become
smaller and the shells harder, which increases the difficulty of selling.
From the standpoint of the grower as well as the market, the lateness in
ripening is very objectionable. The California Almond Growers’ Exchange
is finding it harder each year to satisfactorily market the rapidly
increasing tonnage of this variety. It should, therefore, be avoided in
new plantings.


SIZE OF ALMONDS

Records of fourteen varieties of almonds grown in the same orchard under
similar conditions of soil and culture have been kept at the University
Farm at Davis, for the years 1913 to 1916, inclusive. These trees are all
of the same age, except the Texas, Peerless and Harriott, which are one
year younger than the others. These figures show that there is a wide
variation within varieties from year to year, not only as regards size,
but proportion of shell to whole nut, and in the proportion of double
kernels.

Table X shows the variation in size from year to year, as indicated by
the number of nuts per pound. Five-pound samples of each variety were
used to determine the average size:


TABLE X

NUMBER OF ALMONDS PER POUND FOR YEARS 1913 TO 1916, INCLUSIVE

    Variety          1913    1914    1915    1916   Average

    Nonpareil         256     240     224     223     236
    I.X.L.            149     149     159     150     152
    Ne Plus Ultra       —     163     179     169     167
    Drake             189     132     131     130     145.5
    Languedoc         226     220     185     213     211
    Texas             182     171     165     173     173
    Reams             138     123     143     148     140.5
    Lewelling         154     150     158     139     150
    Peerless            —     118     127     134     124
    Princess          270     241     190     252     238
    California          —     232     211     206     216
    King                —     246     234     244     241
    Harriott            —     175     151     176     167
    Jordan              —      76      70      75      74

The value of an almond for shelling depends not alone on its relative
ease of cracking, but also upon the percentage of kernel to the whole nut
as shown in table XI:


TABLE XI

PERCENTAGE OF KERNELS TO WHOLE NUTS

                   1913       1914       1915       1916    Average
    Variety      Per cent   Per cent   Per cent   Per cent  Per cent

    Nonpareil     67.5        65.0       67.2       67.0      66.6
    I.X.L.        45.31       48.5       60.6       54.7      52.28
    Ne Plus Ultra   —         53.25      57.6       58.5      56.45
    Drake         46.33       42.40      47.0       42.2      44.48
    Languedoc     48.75       50.0       49.4       48.5      49.16
    Texas         43.75       45.0       42.4       44.4      43.89
    Reams         45.94       42.5       49.25      43.4      45.27
    Lewelling     43.44       48.8       50.6       45.0      46.96
    Peerless        —         36.0       39.65      32.5      36.05
    Princess      65.0        73.0       70.6       73.8      70.6
    California      —         71.2       70.6       69.5      70.43
    King            —         70.0       72.0       71.6      71.2
    Harriott        —         56.25      54.2       50.6      53.68
    Jordan          —         25.0       23.8       26.9      25.23

Double kernels are particularly undesirable in nuts for shelling because
of the irregular shape of the halves, which renders them unfit for
confectionery or bakery purposes where whole kernels are used. Table XII
shows the percentage of double kernels by number:


TABLE XII

PERCENTAGE OF DOUBLE KERNELS FOR DIFFERENT VARIETIES

    Variety         1914     1915     1916    Average

    Nonpareil       1.09     1.96     6.10     3.05
    I.X.L.           .50      .50      .80      .60
    Ne Plus Ultra   4.30     5.76    12.06     7.37
    Drake          12.72     6.25     6.65     8.54
    Languedoc        .99      .32     1.60      .97
    Texas          11.56     7.40    11.90    10.29
    Reams           9.92    13.79     4.82     9.51
    Lewelling      13.30    28.70    46.50    29.50
    Peerless        4.44     7.05     8.38     6.62
    Princess         .83      .21     4.61     1.88
    California       .00      .00      .097     .032
    King             .00     1.28     2.13     1.14
    Harriott        1.43      .40      .80      .88
    Jordan          1.32     3.72     3.74     2.93


METHODS OF CLASSIFICATION

Almonds are classified according to hardness of shell, into four classes:

_Papershell._—Those almonds having a thin, papery shell which may easily
be broken between the fingers of one hand.

_Softshell._—Those which have a more or less spongy or thin shell which
may be broken between the fingers of two hands.

[Illustration: Fig. 27.—Almond varieties.

LANGUEDOC. TEXAS. DRAKE.

NONPAREIL. I.X.L. NE PLUS ULTRA.

TARRAGONA. JORDAN. PEERLESS.]

_Standardshell._—Those requiring very strong pressure of the hand or the
use of a nut-cracker to break. These may have a spongy or smooth outer
shell.

_Hardshell._—Those which cannot be broken by hand but require a sharp
blow with a hammer or strong pressure with a nut cracker to crack them.

The papershell varieties are excellent for shelling as they contain a
large percentage of kernels which may easily be obtained whole. The
principal objections are that birds are particularly fond of them since
they can crack them easily, and the shells are often poorly sealed. The
latter fact makes it difficult to prevent worm infestation and to prevent
the penetration of sulphur fumes to the kernel during the bleaching
process. As a result practically none of the papershells are bleached but
are sold for shelling purposes.

The softshells are generally more attractive for table use because the
shells are more perfect and, in commercial varieties, are brighter in
color and more attractive. The shells are usually well sealed and can
be bleached to give additional brightness with less danger of the fumes
penetrating to the kernel than the papershells.

[Illustration: Fig. 28.—Almond varieties.

HARRIOTT. EUREKA. LEWELLING.

KING. CALIFORNIA. PRINCESS.

STUART. LA PRIMA. BATHAM.]

The standardshells have the greatest range in character, thickness
and hardness of shell. For table use they are sometimes too hard for
high-class trade. The percentage of kernel is too low to make them very
attractive to the retail trade. Of this class of almond the Drake is
probably the best of the California varieties. Almond varieties of all
these classes are shown in figures 27 and 28. These illustrations show
most of the varieties grown to any extent in California and others that
have attracted much interest and inquiry, together with the European
Tarragona.




FOOTNOTES


[1] Tufts, W. P., unpublished data from experiments conducted in the
University Farm orchard, at Davis, California.

[2] Colby, Geo. E., Ann. Rept. Cal. Agri. Exp. Sta., 1895-1896 and
1896-1897.

[3] As this bulletin goes to press doubt is raised as to whether some
of these trees may not be on almond stock, but this in no material way
affects the discussion.

[4] Just what conditions will exist after the close of the present war
cannot be forecast with any degree of accuracy. One thing is certain,
the increasing popularity of shelled almonds makes it essential that the
American markets become familiar with the California shelled product, and
that this trade be extended as quickly as possible.

[5] Cir. 121, Univ. Calif. Agri. Exp. Station, October, 1914.

[6] The fumigation of Stored Grain, Dried Fruits, and Other Products, E.
R. DeOng, Cal. Agr. Exp. Sta., Dec., 1917.




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