While it may be hard to believe most weeds blow into your lawn as seeds and sprout the minute they find enough bare soil moisture and light to grow. This is true for both annual weeds and perennial weeds. Annual weeds sprout grow flower seed and die within one year. Perennial weeds sprout from a seed as well but the weed plant continues to grow and spread for more than one season even though the top may die back in the winter. Unfortunately fescue lawns weekend during our hot Southern Summers and a thinning lawn is the perfect place for weed seed to germinate and grow. Consequently your ultimate goal becomes to grow a thick luscious lawn that will actually prevent weed seeds from germinate. There are two ways to accomplish this. First correct fundamental problems like shade poor drainage and soil compaction that make growing a thick fescue lawn difficult at best. Second stay on top of your lawn maintenance. Fescue lawns need to be nurtured during the summer and a couple of weeks without water or mowing can be devastating. Even then you will need to incorporate in a weed control program into your yearly maintenance activities.