I have a few customers who want to have their yard rototilled and have grass seed or sod put in its place, the problem that I see is that there is crabgrass in the lawn right now. They are somewhat impatient and just want to get the job done, but my thought is that very soon after the crabgrass will soon emerge again in full force. I am considering the use of Round Up, though I have seen that it does not completely get rid of the crabgrass and I don't want to be responsible for the lawn getting the crabgrass back. Then there is the herbicide that I see on the shelf that kills plants but says there is a 1 year period before planting in the same area. What to do to meet these costumers wants?