I want to say up front that I do not do chemical applications. I leave this up to the customer to self apply or obtain a seperate contractor. I have one customer that has a thin area in the lawn and asked If I could overseed it to thicken it up. The problem is that the customer just applied Scotts with the crabgrass control. I asked a guy and he said four weeks. Is this accurate. Do I need to do anything special because of the chem application?