Q: What are the physiological processes involved when fescue thins out during the summer in the heat and humidity in Atlanta?
A: Turf expert Clint Waltz calls it “summer swoon of fescue”. Thinning is a survival mechanism caused by water stress and exposure to high temperatures. Air temperatures above one hundred degrees and soil temperatures above seventy five degrees disrupt fescue grass cells’ normal functions.
Clint says fescue should be irrigated to avoid wilting in summer but only to supplement natural rainfall, not to exceed one inch per week. Don’t fertilize; the root system is limited in its uptake ability and there is no need to stimulate a stressed plant which does not want to grow under adverse climatic conditions.
Raise the mowing height to three and one-half inches. This encourages the deepest possible rooting and helps shade the soil surface, which reduces water loss and soil heating.
The last suggestion is the most difficult for most homeowners: be patient and wait for environmental conditions to change.
“Tall fescue is hardier than it is given credit for. Once the weather changes in September, most people will be surprised how much of their tall fescue survived the summer swoon.”