Well it mainly depends on the type of strain your growing however most plants take anywhere from 8-10 weeks to flower to maturity, so its really hard to tell. I would suggest the best time to harvest is when slightly over half of the hairs have turned a slight brown tinge, and all the tiny capsules on the plant are standing straight up with lil caps ontop
hope this was helpfull
Jay
Lets smoke that bowl
Hit the bong
And then take that finger off of that hole
Plug it
Unplug it
Dont strain
I love you mary jane