In other words, if tall fescue is being cut at 2 inches, it should be mowed when it reaches 3 inches. Irrigation Proper irrigation is very important to maintain a quality lawn, and tall fescue generally requires more water than other lawn grasses in Georgia. Irrigate only when the grass shows signs of moisture stress, such as off color, wilting or rolling leaves. Then apply enough water to wet the soil to a depth of 4 to 8 inches. This generally requires about 1 inch of water, which should last 7 to 10 days.
Early morning is the best time to irrigate, while evening irrigation is more efficient.
A dense, healthy turf provides the best defense against weed invasion and other pest problems. It is very difficult, however, to maintain a nice tall fescue lawn without using a herbicide to control crabgrass. Fortunately, many preemergence and postemergence herbicides are available to use on tall fescue lawns, and preemergence herbicides applied in early spring are the preferred method of crabgrass control. Common bermudagrass invasion of tall fescue lawns is a common problem that is difficult to overcome. In some cases, an application of a non-selective herbicide that kills all vegetation is needed.