Hi grower, you may select best time by checking pistils (the ‘hairs’ on your buds). The pistil method isn’t nearly as accurate as checking the trichomes (the ‘glitter’ on your buds), but it’s definitely a good place to start since you can just look at the buds and get a general idea.
Harvest when 70-90% of hairs have darkened for highest levels of THC.
Harvest when 90-100% of hairs have darkened for a more calming,
anti-anxiety effect as some THC turns to the more relaxing CBN.
BUT!
Better buy a microscope or a magnifier and google how to recognize best time by checking trichromes! Good luck!