How long have the plants been flowering? It looks like they are still way too young to think about harvesting. The buds can still double in size before they are ready. You can usually eyeball it when ready to harvest by checking out the pistils. But like everyone else is saying you have to use the microscope and check out the trichromes to be 100%.

The pistils start out a lighter color, then will turn dark. Usually they start white then turn brown or red. The bud starts to put on the most mass when the pistils start to wilt up and die. That is the perfect time to check out your trichromes. An early harvest will be an energetic head high, a late harvest will be more of a couch-lock high. The trichromes start out clear, turn milky white, then turn amber brown. I am planning on harvest when they are 75% white, 25% amber.
airdawg13 Reviewed by airdawg13 on . Help! Not sure if I'm ready to harvest. Please help. This is my first time growing and I don't know if I should harvest yet. Rating: 5