Now that we’ve had a week with no rain growers need to begin irrigating pecan trees as needed. Pecan trees need a significant amount of water (as much as 350 gal/tree/day) as they are filling the kernels in August and September. While they need good soil moisture throughout the growing season, the demand for water is much less early in the season than later. The trees need water for growth and expansion of the foliage as well as for development of flowers and crop set in the spring. As the nuts begin to size, the demand for water increases so growers need to begin applying water at low rates early in the season and increase as the crop develops. We are fortunate that in the Southeastern U.S., we normally get enough rainfall throughout the year to account for at least 30-50% of the tree’s water needs. The problem is that the distribution of that rainfall does not always match the time when the tree’s need it most. The table below summarizes our irrigation schedule recommendations for bearing pecan trees in Georgia. Take note that the irrigation can be turned off for 3 days following rainfall events of 1″ or more per day. Orchards on sandy soils should lean toward the high end of the recommended range, while clay soils can lean to the low end.
We know that young, non-bearing trees (<5 yrs old) do not require anywhere near the amount of water applied to mature trees in late season. While we don’t have firm, research-driven numbers to provide for irrigating young trees at this point, we are currently in the process of developing these. In the meantime, the April or May rates applied to mature trees will work season long for young trees because there is no crop demand on them.