As a general recommendation, apply 1 pound zinc sulfate per tree for the first three years after planting. Spread the fertilizer and zinc sulfate in a circle around the tree outside of the planting hole. If the trees are to produce a good crop, terminal growth should be 6 inches each year. This fertilizer should be applied in mid- to late February. Zinc nutrition is especially important in pecan production.
Zinc deficiency is called rosette.
Zinc needs are best determined by a laboratory analysis of leaf samples taken in late July or early August. Kits and instructions for taking leaf samples are available from any Clemson Extension office. The leaf tissue analysis report will tell you how much zinc to apply. In the absence of a tissue analysis, apply 1 pound of zinc sulfate to young trees and 3 to 5 pounds for large trees each year. A soil pH of 6.0 to 6.5 assures the availability of essential nutrients.