Lime Application Rates for Pecan Trees

Purpose of Lime

• The lime requirement for any plant, including pecan trees, is best determined by a soil test. Lime isn't a fertilizing agent and isn't added to soil to be absorbed and used by the tree, as nitrogen, phosphorus or potassium are. The purpose of lime is to change the soil's pH from acidic to alkaline or neutral. The soil's pH is measured on a scale of 0 to 14, with less than 7 being acidic, more than 7 being alkaline or base, and 7 being neutral.

Lime Requirements

• Pecan trees grow optimally in a soil pH ranging between 5.5 to 6.5, as recommended by the University of Florida Extension. In soils with a pH less than 5.0, add 1 to 2 tons of lime per acre. Soil often turns acidic with consistent use of nitrogen based fertilizers. Add a pound of dolomite lime to 100 square feet of planting ground to raise the pH by one unit. The best time to apply lime is during fall. Mix the material well into the soil.

General Recommendations

• The Alabama Cooperative Extension has made some general recommendations regarding lime applications in pecan trees. Apply 5 lbs. of dolomite lime to the tree per year of growth. For instance, a 3-year-old tree needs 15 lbs. of lime while a 5-year-old tree requires 25 lbs. Don't exceed 100 lbs. of lime for a tree of any age. Lack of lime in the soil is among the main reasons for reduced fruit yields.

Fertilizer

• The fertilizer requirement for pecan trees is determined by soil tests taken from different places in the planting site. Don't place any fertilizer directly in planting holes at the time of planting as this can cause root burn. Fertilize the tree lightly with a pound of 10-10-10 fertilizer with micro-elements twice a year, in March and June. Spread the fertilizer around the tree in a 3- to 5-foot diameter starting a few inches away from trunk. Generally, pecan trees require 2 lbs. of fertilizer for every inch of trunk diameter two times a year. Trees with trunks measuring 30 inches require 60 to 120 lbs. of fertilizer twice a year.