if your growing a sativa dominate then that sounds right, but if its a indaca dominate then thats to long. what you need to do is get your self a 420 scope at 60x to 100x zoom and look at the tricombs, your supposed to harvest when the trics are 50% amber 50% clear or cloudy for the strongest possible high. do some research on the net......I generally wait like 3 months until I harvest, and Im currently using KC brains, thier mango.