The best and most accurate way of knowing when your plants have reached peak maturity and are ready for harvest is by trichome colour. Do you have a 30x-60x microscope or jewelers loupe? If not it is very hard to do this without one. It requires high magnification to see the tiny trichome heads colours. When the trichomes are clear, this means they are undeveloped and immature. When the trichome color turns milky/cloudy, this means the trichome has reached its peak potency, when the trichome heads start turning from amber, to dark brown to black, is when you need to pay attention. Black trichomes means the trichomes mturity has passed and the THC has degraded. Amber means its still within maturity but for not much longer. I personally aim to harvest at a 10% amber 90% cloudy/milky for a more energetic, head cerebreal high, If you enjoy the more body stone, couch locking buzz, you would aim for more of a 50/50 mixture of amber to milky. I do not recommend going past a 50/50 mix as THC will be degrading daily from this point on.
Pistil colour is not a accurate way to gauge maturity and harvest times so I do not recommend that.
http://www.420magazine.com/gallery/data/500/when-to-harvest_1_.jpg
I should add thats trichomes are constantly forming and growing, maturing and degrading. Due to this you will never get say, 100% Milky/Cloudy trichomes, you will always notice new spots developing.
Always gauge trichome colour on the section of the BUD, do not gauge colour on the fan leaves as they seem to mature earlier than the bud.
