Get a microscope and see if the trichome heads are milky, if so, your buds are ripe and have THCA. If your trichome heads are turning amber it's time to harvest. The longer you let the trichomes be exposed to light & air they will start oxidizing and your THC will turn to CBN. CBN gives you a more sleepy/relaxed/stoned effect. To me they look harvestable but I'm just going off the faded leaves, golden/amber hairs and days on that strain as I've grown it myself in the past.