Pecan Growing Guide

Selecting a Variety

Care Before Planting (Heeling in Your Plant)

Realize that all bare root stock, though dormant, is also in a state of shock.  They have been dug up from the field with an inevitable loss of roots, and need special care even before planting.  The most important thing to remember is KEEP THE ROOTS MOIST. Even for brief periods, i.e. while transporting them to the planting site.  If you have not pre-dug the holes for your trees and must keep them for more than a few days, they should be HEELED IN (buried in a moist medium), in a shady spot and watered thoroughly.  Keep the roots packed in sand, peat moss, potting mix or aged sawdust (avoid fresh sawdust or wood shavings as they may contain compounds that inhibit root formation).  Trees can be kept like this for several weeks if necessary, but should always be permanently planted before showing any signs of bud swell or growth.  Protect trees from freezing before planting.  Prior to planting, SOAK TREES IN WATER FOR 12 TO 24 HOURS.  This will afford them a good long drink to compensate for any moisture loss in storage and shipping.

Selecting Best Planting Site

The most important factors to consider in choosing a site for planting pecan trees are: soil type, depth, and drainage.

Pecans will grow in almost any soil in southern states, except poorly drained soil, hardpan or stiff clays, or thin sands with a high water table. Soils for planting pecan trees may be red, brown, or gray in color, but it is necessary they contain sand or sandy-loam and that the subsoil be of clay or semi-clay structure. It is most important that the soil should have good water holding capacity. For proper root penetration, it should be several feet deep.

In selecting a planting site, keep in mind the desirable soil characteristics described above. Avoid badly eroded hills. If not eroded, hilltops and north, east, south, or west slopes are satisfactory. In most cases, even bottom land along streams has proved a good location if well drained. The greater movement of the air often causes faster drying of morning dews and rains which help prevent scab infection.

In addition to the above, select a planting site away from buildings and power lines. Always consider the mature size of pecan trees when deciding on a planting site. If planting more than one pecan tree, space at least 40-60 feet apart so they have adequate space to grow.

Pecan trees can be planted as bare-root or container-grown. Bare-root pecan trees should be transplanted during the dormant season; mid December through early spring are preferred. Container-grown trees are less likely to receive transplant shock if planted while dormant, but with adequate attention and irrigation, they can be planted October through June.

Transplanting

To plant, dig a hole at least 24 inches wide at the bottom and 2 ½ to 3 feet deep. If planting bare-root, soak roots in water for 24 hours just prior to planting. Examine the roots and remove all broken or injured roots but keep root trimming to a minimum. Occasionally the taproot and/or some of the lateral roots will need to be pruned to fit the hole. Never twist lateral roots in the hole as this could eventually cause death to that part of the root system.

Plant the tree level with where it grew in the nursery (i.e. the soil line, which is indicated by a color change on the bark) but not too deep. Fill the hole about ⅓ full of topsoil and saturate the soil with water to settle, repeating this operation until the hole is almost full. Have a soil test done to determine the pH level of the soil, and if the soil is below 5.6 add lime to your soil as the hole is being filled to raise the pH. Once the hole is filled, construct a basin around the tree 3 or 4 feet in diameter and 6 to 8 inches deep.

During the first growing season, water the trees once a week on clay soils and twice a week for light soils. The roots of a bare-rooted tree help to provide anchorage and to serve as a source of new feeder roots following transplanting, but they are of little value in direct absorption of moisture and nutrients from the soil. New roots are necessary for this function, and they develop from the older roots. The tree must remain alive during the critical period of new root development, which is slow. So, for this reason adequate moisture must be available to the tree throughout the entire first summer.

As soon as trees are set, prune the top to balance with the roots. For bare root, prune ⅓ to ½ of the top, and for container pecans, prune about 10 percent off the top. Make the cut just above a healthy bud.

Care of Young Non-Bearing Trees

To get good growth, prune no more than necessary. The larger the number of leaves left to grow, the more food will be manufactured for more rapid tree growth. Cut out narrow crotches early to prevent serious splitting when the tree comes into heavy production. Try to space the lateral limbs equally around the trunk of the tree, and have each limb at least 8 inches above another. Select three to five branches for the permanent scaffold system. The lowest of these branches should be no less than 6 feet above the ground.

The pH range for pecans should be from 5.6 to 6.5. To determine the pH, have the soil tested through your local county extension agent, and he or she in turn will suggest the amount of dolomitic limestone to apply, if any is needed.

Newly transplanted trees should NOT be fertilized at the time of planting, but should receive 2 to 3 pounds of 8-8-8 or 10-10-10 containing at least two units of zinc per tree in May the year they are transplanted. Be sure to keep the fertilizer at least 12 inches away from the trunk. Each succeeding year until the tree begins production, apply 1 pound of 8-8-8 or 10-10-10 plus minor elements for each inch of trunk diameter measured one foot above the soil surface – apply in late February or early March.

Strive for an average terminal growth of about 3 feet annually. If the growth is shorter than this, apply additional nitrogen at the rate of ½ to 1 pound of ammonium nitrate or an equivalent amount of nitrogen from another source of quickly available nitrogen.

For their first three years, pecan trees require 10-15 gallons of water at regular weekly intervals either through rainfall or irrigation. 

Pollination and Fruiting Habit

The male flower and the female flower of the pecan are separate, but they are on the same trees. The male flowers, commonly known as catkins, are produced from lateral buds on the previous season's growth. These buds are formed late in the previous season.

The female flower, a tiny nut-like flower with flared terminal ends, is produced at the end of the current season's new growth. The flared ends (stigmas) of the tiny nuts are the portion of the female flower on which the pollen falls when pollination occurs. Since the female flowers are borne on the current season's growth, the tree must have stored an abundance of food from the previous season. Also, an adequate amount of fertilizer should be applied early enough – late February or early March – to be effective.

Pecans are pollinated by wind only. When the catkin matures, the pollen is released. The pollen floats in the wind, and by this means it reaches the flared tips or stigmas of the female flower. Pollination then occurs if the pollen is viable (alive) and the stigma is receptive. Should the catkins mature before or after the female flower is receptive, pollination does not occur. And should heavy rains occur during pollination, the pollen will not be wind borne and pollination will be poor. Thus, to assure pollination, it is important to plant more than one variety in an area.

Care of Bearing Trees

To realize good annual production, trees must be adequately fertilized and insects and diseases controlled. You can determine whether an adequate amount of fertilizer has been applied by the amount of terminal twig growth. An average annual growth of 6-8 inches is ideal, with 4 to 6 inches as the minimum, if trees are expected to produce large crops.

The recommended fertilizer program should be determined by your soil test but a general rule is to apply 4 pounds of 8-8-8 or 10-10-10 fertilizer per inch of trunk diameter measured 4 feet above the soil line. Apply fertilizer in late February or early March. On sandy soils split application can be made – the first half being applied in late February or early March and the second near blooming time in May. To prevent deficiency of zinc and other minor elements, the 6 fertilizer listed above should contain 1 to 2 percent of the deficient minor element(s). Lack of enough zinc and nitrogen reduces production more than any other factor.

Apply fertilizer beneath the spread of the limbs and beyond the edge of the limbs to a point equal to the distance from trunk to limb-spread. If a lawn grass is not present, broadcast fertilizer on the soil surface and water into the soil. Where trees are in the lawn, do not spread the fertilizer on the surface as injury to the grass may result. Instead place fertilizer beneath the soil surface by plugging or probing.

Use post-hole digger, probe, or orchard auger to place the fertilizer below the soil surface. If a post-hole digger or auger is used, remove the sod plug and then dig a hole about 6 inches deep. Place the fertilizer in the hole, replace the soil, pack, and replace the sod plug. If a probe is used, it should be at least 1 inch in diameter and have a sharp point. Force the probe into the soil about 12 inches deep. Remove the probe, and fill the hole with fertilizer up to within 3 inches of the top. Close the top of the hole by packing the soil along the side with the heel.

Zinc deficiency is called rosette. The most common and noticeable symptoms of rosette are the following: bronzing and mottling of leaves; early defoliation; dead twigs in top of trees; abnormally small nuts; small yellowish chlorotic leaves; short thin twigs growing on older scaffold branches with rosette of small yellowish green leaves at the tips. An early sign is wavy margin of the leaflets.

The most important factor influencing yield is proper fertilization including zinc to prevent rosette. Controlling diseases and insects is equally essential.

Alternate Bearing

Pecan trees tend to exhibit alternate bearing, meaning that a high production year is followed by one or more years of low production. This happens when trees set a large nut crop and nutrients and moisture are not enough for the nuts to mature and for the tree to store enough plant food causing low production the following year. Early defoliation in the fall usually means no nut crop the next year.

Diseases and insects affecting the leaves also contribute to alternate bearing by causing early leaf drop in the fall. To help prevent alternate bearing, use sound cultural practices. These include disease and insect control, adequate use of fertilizer and zinc, and an extra application of fertilizer in late May or June in years when nutset is heavy. Keeping healthy, dark green leaves on the tree until first frost is a sure step toward achieving annual nut production.