crabgrass

overseed the tall fescue, mow at three inches, fertilize now and in October, and let the fescue crowd out the crab grass.

-kelly

Crabgrass seeds can remain dormant for over 15 years. Ortho has a new product out called "Weed-B-Gone Crabgrass Killer," and I'm currently trying this out on a fescue lawn. Traditionally, you apply a pre-emergence in early spring, then apply again after 90 days. Overseeding helps a lot. Mow high and often. Crabgrass likes hot sunny bare areas. You can pull them out by hand, if there is not too much. Whatever you do, do not let the crabgrass produce more seed!