my standard procedure is : thatch, aerate, powerseed, fert. i did a few like this, and have alot of new grass in a weeks time. the ones i did two weeks ago, look great too. now, i've read here where you guys say "no need to thatch, just aerate and seed." well, i tried it, today i visited the ones i did like this over 2 weeks ago. the results were TERRIBLE. no new grass. what's the deal?