Fertilizing
Maintaining a good fertilization program can keep your plants vigorous and help prevent infections
of bacterial blast or canker, oak root fungus, and powdery mildew.
As a general rule, nitrogen should be applied annually, usually during the growing season. To improve
fruit quality and color, nitrogen levels should be low but not deficient as the harvest nears.
Nitrogen fertilizer can be applied in the spring or split between spring and just after harvest.
Excessive
nitrogen can cause softer fruit, poor fruit color, and reduced storage and shelf life; it can also
increase problems with numerous pests. Typically, mature trees should receive about 3 - 5 pounds
of ammonium sulfate per year or 2 pounds of urea per year depending upon soil fertility and local
growing conditions. Apply well away from the trunk and water thoroughly after application.
Zinc is also commonly deficient. Affected trees have small new leaves. This deficiency is best
corrected by spray applications. Spray with a "chelated zinc" during the growing season. Repeat if
new growth still shows deficiency symptoms. | 
Small
leaves caused by a deficiency of zinc |
