Hey Growmie ...
Use the Pistil Method to check whether it's harvesting time. Make sure that at least 70% of the pistils have turned amber before harvesting to get optimal THC levels. I would also advise flushing the plant with pure ph balanced water also for a week to remove the excess nutrients from the soil.
Hopefully, this was helpful and remember ..."Happy Growing" and "Free your mind one puff at a time"
Mr_Weeds_Autos.