To ensure good nut production, you must fertilize your pecan trees properly. Pecan trees often suffer from zinc deficiencies, which cause the branches to grow thick knots of leaves at the tips and limit pecan production. The best way to determine exactly how to feed your pecan tree is to analyze the soil. Take a soil sample near the roots of your pecan tree and have it analyzed by your county agricultural extension office. The soil analysis will give you an accurate picture of the soil properties, including nitrogen and zinc deficiencies. In the absence of a soil test, you can use some basic guidelines to feed your pecan trees.
Measure the width of your pecan tree's trunk at chest height in inches.
Spread 1 pound of 10-10-10 NPK (nitrogen-phosphorous-potassium) granular fertilizer for every 1 inch of trunk thickness that you measured. Fertilize the pecan tree at this rate once in mid- to late February, once in June and again in September.
Broadcast the granular fertilizer in a ring around the tree, beginning at 3 feet away from the trunk. Spread the fertilizer so that it extends 2 or 3 feet past the canopy's farthest-reaching branches.
Feed your pecan tree 1/2 pound of 36 percent zinc sulfate for every 1 inch of trunk thickness, up to 10 pounds per tree. Apply the zinc sulfate once per year in the spring in the same manner as the complete fertilizer.
Water the soil around the pecan tree thoroughly immediately after broadcasting the fertilizers to allow the granules to dilute and seep into the soil.