A lot of hairs will develop, the buds will begin to fatten up and the hairs will start turning brown. The trichomes will start to appear milky instead of clear, then begin to turn amber. The more amber you see the more mature the plant becomes. The smell intensifies as well. As far as when to harvest, as soon as you see amber and the hairs turn brown your in the window. It becomes a personal preference and what kind of high you’re looking for. A mind or body buzz or combination of both.