A decent tiller should not have a problem tilling in
grass..........but just read whats on the herbicide container and go
from there. There is too many brands out there to say, but generally
it has to be applied X amount of time before any rain, and left for X
amount of time before planting etc. Read the instructions and
recompendations on a few herbicides next time your in wally world.Will
seeds that germinate after be aproblem, if so maybe a pre emergence is
going to be needed as well.