ok, today when i mowed i took OFF the thatcher and bagger and simply discharged the grass clippings into the yard. i have yet to apply ANY type of fertilizer or herbicide. so are you saying i should NEVER dethatch or ONLY dethatch in the fall - sept or oct. - after the lawn has fully matured through the summer. I was under the impression that spring dethatching and aerating (2 in 1 was my assumption as thatcher creates aeration when used) was the correct time to do that. i was also under impression you should dethatch BOTH spring and fall. man its a good thing we caught this early!!