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.
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.