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.