Hi my friend :-) . First of all you have beautiful plants there 😍🌱💪🏻😎. To be 100% accurate, you have to look at the trichomes (resin glands) with a microscope. If the heads are all milky, you can flush them, if part of the heads are amber, you can harvest them :-). Carry on so you are doing great 👍 if you have any further questions we are at your disposal :-)