Q: I would like to know how to fertilize my pecan trees. I have two large trees and they have always produced more than I could ever use or even give away.
A: I have strong memories of my Dad piercing the soil under our pecan with the sharpened tip of a buggy axle. I would follow behind, filling the holes with 10-10-10. Old-timers believed that lye provided potassium to pecans. I’m sure it did, but the caustic substance killed lots of roots too!
Pecan trees produce nuts based on how many leaves were present the previous year. The best way to have lots of leaves is to fertilize regularly.
Go to each of your trees and measure how thick it is at chest height. For every inch of thickness, broadcast a pound of 10-10-10. Do this three times a year; in late February, in June and in September, up to a maximum of 25 lbs. per tree per year.
For large, mature trees the fertilizer can be applied at one time in early March.
In addition, apply one pound of zinc sulfate (click for sources) to 4 – 10 year old trees and three to five pounds for large trees each year. This prevents pecan rosette, which causes limbs to have thick knots of leaves at the ends.