this is what i posted on another forum: i had a person call me today and want a price on getting grass to grow on her lawn.. she said it's mostly just weeds.. in this case would i just overseed what's there and put down a post emeregent later? or do i put something down now to get rid of the weeds and reseed later? and someone emailed this to me and i wanted to know if it would work... Hey saw your post about a yard w/ mostly weeds. What about just doing a complete kill w/ Round-Up? Yes, you can do it the other way but as mentioned it will take 2-3 yrs. Kill everything now, till & reseed. Customers want results now! and 2-3 seems like it would only be good for that especially patient customer. If you read the label on Round-Up you can reseed in as little as 24 hrs. I myself would wait until the plant has fully absorbed and translocated the pesticide (complete to the roots) until tilling and seeding. Besides if you just leave the weeds and overseed I think you'll get very poor growth as the weeds will compete w/ and choke out any new grass seed trying to grow.Wouldn't that make sense? These are my suggestions. I'm not putting them on the board b/c I don't need somejerl arguing w/ me and telling me "I" don't know what I'm doing. Sorry "Bud" but 10 yrs. experience tells me otherwise. Hope this helps.