[williecoyote]

I'm going to guess that you have a Fescue lawn which has been invaded by Common Bermuda. What you have is two competing types of grass. The Fescue is a cool season grass, and the Bermuda is a warm season grass. They have different growing seasons, and different requirements. Bermuda creeps, and eventually will take over. This is most likely what has been going on. Fescue does not creep. Plant one seed, grow one chute. You maintain Bermuda low, and it will grow thick, and choke out the weeds. Maintain Fescue tall, and it will shade out the weeds. Fescue does not spread, so you have to scratch, and seed the bare spots. Bermuda loves the heat, and grows well spring through fall. Fescue doesn't like heat, and it grows best fall through late spring/ early summer.

Pick one, and kill the other. Then get on a maintenance program for whichever you prefer. Nice lawns don't happen by accident. Is your yard sunny, or shady? Bermuda likes full sun, Fescue will tolerate partial shade.

The best Fescue lawns are reseeded every fall. If you seed now, it will germinate, and come up, but the roots won't be well enough developed for the grass to withstand the summer heat, unless you can water it.