All fruit trees to be grown in pots should be propagated on the dwarfest of dwarfing stocks. This means practically that apples should be on Paradise, pears on quince, peaches and nectarines on sand cherry, plum on sand cherry or St. Julien plum, and cherries on Mahaleb.
FIG. 41—A FRUITING PEACH IN POT
The trees should be potted in good rich soil, preferably the best garden loam. This should have enough sand and gravel in it to insure good drainage. A considerable amount of drainage material should be placed in the bottom of each pot. The trees should be repotted in fresh soil annually in October or November.
Trees in pots require liberal feeding. Besides being given well enriched earth at the time of repotting, they should be supplied from time to time with small amounts of fertilizer. Good soluble chemical fertilizers can be applied either dry or dissolved. A good formula is one part nitrate of soda, two parts of muriate of potash, two parts of high grade phosphoric acid. A very little sprinkling, say a tablespoonful, of this can be given on each pot once a month during the growing season which lasts roughly from December to May. In place of this, or alternately with this, moderate waterings with liquid manure may also be given. These small doses of food are especially useful at the time when the fruit is forming on the trees.
The trees are usually brought into the house at the time of potting, say November 1. If early fruit is desired, they are kept in a house with some heat. It is necessary only that the temperature should be kept constantly and safely above the freezing point. Rapid forcing with a high temperature is not desirable and is hardly possible. If kept simply above the freezing point, these trees will start into growth in January. They can then be kept somewhat warmer during February, the heat being slightly increased in March. Peaches and nectarines will stand fairly high temperatures after the fruit is well set and especially toward ripening time. By this method of mild forcing, plums, peaches, and nectarines can be brought into fruit as early as the latter part of May.
FIG. 42—A FIG TREE IN A POT