How soon do you jump out there and do your de-thatching? I'd like to say that as soon as it's good and dry out there, hammer them out. This way i can hurry up and apply my crab grass preventative in the first of april til the first of may. I was wondering, should you allow the lawn to really green up before power raking it? Or is it alright to do it while it's still dormant? just wondering bout that, thanks.