There are several ways to encourage weeds and other issues in your lawn. One of these is fertilizing your tall fescue lawn at the wrong time of year. September and November are the most important times to fertilize tall fescue lawns. Fertilizing in March or early April promotes excessive growth that increases mowing and encourages disease and weeds. Delay fertilization until top growth slows in May. Then apply a slow-release nitrogen source, which keeps grass from growing too fast as hot weather approaches. Too much top growth prevents root growth needed to withstand summer stresses. If fertilizing only once a year, do it in September to thicken the lawn and promote root development.
A November fertilizer application helps the lawn stay green longer and encourages it to green up earlier in the spring. Fertilize with 1 pound of soluble nitrogen. Soak soil thoroughly before winter.