Fruit Tree Care (cont)
By: National Gardening Association Editors
Fertilizing Year 2
During the second growing season, make two fertilizer applications: one when growth begins in spring and one in early summer. Apply about 1/8-pound of actual nitrogen each time, if growth was in the desired range last year.
Fertilizing Established Trees
Established fruit trees require little fertilizer other than organic matter. From the third season on, apply only enough nitrogen to produce the desired amount of growth. Bearing trees that produce crops on 1-year-old branches (peaches, apricots, and Japanese plums) should make 15 to 18 inches of terminal growth per season. Those trees which bear mainly on spurs (apples, pears, cherries, and European plums) should make no more than 10 to 14 inches of terminal growth per season.
Nutrient Deficiencies and Excesses
Excess nitrogen can cause poor fruit bud set, poor fruit color, delayed fruit maturity, and softer fruit, which is more prone to rot and doesn't store well. Time fertilizer applications so that nitrogen will be released when growth is starting in spring, and when fruit buds are forming in early to midsummer. Established trees usually don't benefit from phosphorus applications in most soils, and excess phosphorus can cause zinc deficiency. Potassium may be deficient on alkaline soils high in calcium and magnesium. Potassium deficiency reduces fruit size, sugar content, and storage time; it can be recognized by small, bluish-green leaves with yellowed or dying edges. Zinc and boron must be applied frequently on western, alkaline soils. These are best applied as foliar sprays; ask your county Extension Service agent for details. You can apply liquid seaweed emulsion throughout the growing season to provide small amounts of trace elements and cytokinins, growth hormones that reduce stress on the tree. Foliar nutrient sprays can be added to pesticide sprays.
Fall and Winter Care
Each fall, fruit trees begin to harden up in preparation for winter. Growth slows and metabolic changes take place that enable plants to withstand much lower temperatures without damage. Help the plants harden by allowing their growth to slow. Don't apply too much fertilizer or apply it past midsummer because high nitrogen levels will cause continued growth. Don't water from early fall on, except when less than 1 inch of rain has fallen during a 2-week period. Mow around the fruit trees less often in early fall to allow the lawn or groundcover to compete and help slow tree growth. Do not prune in fall, so as not to stimulate growth or leave fresh cuts open to winter injury.
During the winter, desiccation can cause as much injury to plants as cold temperatures. Water trees well in late fall (not early), after they are dormant, but before the ground freezes, if the weather has been dry. Rake fallen leaves. Compost them only if you're sure they are disease-free.