When are the plants ready to harvest?

First pic is a sugar leaf. Ignore trichomes on leaves. This is more art than science. Trichomes are probably th emost correlated for choosing 'best potency' but sometimes trichomes don't amber up and you rely on other observations. So, pay attention to more than just trichomes. Usually when you see amber start up top, there's still quite a bit of ripening remaining for buds lower on the plant. You can always harvest tops and wait for others to catch up if you find a specific ratio of amber that you prefer (only through experience of trial and error will you learn that). I've tried that before but i couldn't tell the difference, lol, so i stopped with the hassle. YMMV. Once my zone of good nugs looks good, i'm harvesting it all. The top tends to be slighly more amber than the mids, but again.. i can't tell a difference. lots of personal preferences invovled.. take notes.. take pictures.. get comfortable. Just as nyquil knocks some out and makes others hyper, you may find you prefer something different than you expect based on anecdotal knowledge that's vastly unverified or tested. The 'amber' does correlate to sleepy buds for the most part, that is not anecdote. That's the known molecule thca breaks down into (whether any intermediary steps being irrelevant). THC has little to no color. Cloudy is maybe the plateau, and amber is definitely degredation, but very likely some amber is the point at which the overal average of the harvest is best... again.. without quantitative studies, relying on anecdote, so i expect 'something' to be a little off.