I have a question I can't seem to get a straight answer to. I plan on overseeding my lawn within the next 30 days. No surprise, I have multi tiller crabgrass. Do I need to kill or remove (pull) crabgrass prior to overseeding? Or can I reseed over active crabgrass after dethatching? If I decide to kill crabgrass with Drive, do the dead roots inhibit overseeding?