Many homeowners are noticing weeds in their turf this time of year. It is very common to see crabgrass and other weeds in your lawn right now. The pre-emergent that was put down to control weeds in the summer is designed to break down by now to make way for seed germination. Fescue turf should we aerated, fertilzed and seeded in September / October to encourage new growth and strenghen existing grass. If the pre-emergent weed control was still active it would not be able to discriminate between grass seed and weed seed. The good news is that as the temperatures start to drop you will see the crabgrass dying off.
With good spring and summer applications of pre-emergent it will help prevent the crabgrass from coming back until next fall.
Weeds are the price you have to pay for new, green grass.