Fertilizer applications have traditionally been applied to pecans in March or April. In sandy soils or when a small pecan crop is expected, the fertilizer application is often split with half being applied in the spring and the rest in mid-May. If a small nut crop is present the May fertilizer application is normally omitted.
First year trees that are growing rapidly can be fertilized with ½ pound of ammonium nitrate or ammonium sulfate in June. Fertilizer should not be applied to trees that are not growing rapidly the first year. Nonbearing young trees in following years should be fertilized at the beginning of the month in April, May and June. Do not fertilize nonbearing trees after June. It could delay dormancy and cause winter damage.
Several pecan horticulturists are recommending that commercial orchards use late season fertilizer applications in July or August to increase nut quality and to reduce alternate bearing. There is research data to back up their recommendations. Unfortunately, the findings are not clear since there is also research that shows no benefit from late season fertilization.
The Pecan Research-Extension Station is conducting research to determine if late season fertilization is beneficial in improving nut quality and reducing alternate bearing. Preliminary findings have currently not shown any benefit to late season fertilization. Several years of data will need to be collected to determine the effect of late season fertilization on nut quality and alternate bearing.
Question answered by Dr. John Pyzner, LSU AgCenter pecan and fruit extension specialist.