Fescue lawn that's gotten eaten up by crabgrass. What can be applied considering the small window I've got before September? I hate to do a blanket spray of roundup on it because there's still plenty of good turf in there.
I 2nd the tenacity vote. Not sure what the label says exactly, but when seeding tttf and kbg I applied due to its ability to be applied at seeding and broad spectrum it covers. Thus far, lawn thick and lush and no crab grass
Just before it goes to seed--let the crabgrass get tall--then cut it short as you can. Shocks it. Power rake. Sow seed and starter fertilizer. In fall, cool weather and falling soil temperatures will stop new crabgrass and crabgrass seed, if it gets down to 45 degrees at night. If you feel the need for crabgrass control--then use Drive.
Or apply Tenacity.
Big C is right--Drive is hard on fine fescue--slight risk of injury.
Arrange for plenty of water. Water every day for 30 days.