https://www.alchimiaweb.com/blogen/harvest-marijuana-plants-trichome-ripeness/

Oof. I’d highly recommend doing google research on this yourself, spend at least 15-20 min doing some reading from what looks like reputable sources - rather than going from this smorgasbord of information.

Most people will say yes to the trichome colour theory, that is, to harvest at between 10 and 30% amber trichomes, but I disagree with this theory as not all plants get amber trichomes and others will have 80-100% amber trichomes from the forth week onwards. I suggest harvesting according to pistil colour, as pistil colour is a direct link to plant condition/health and it is plant condition/health that determines trichome chemical composition. Harvesting when there are about 95-98% brown pistils will give you flowers with peak THC and peak terpene levels too, giving you a mind bending head trip effect. Harvesting when there are 98-100% brown pistils will give you flowers with declining THC levels and rising CBD and CBN levels, giving you a more body type of stone or "couch lock" effect. Coincidently, 95-98% brown pistils usually results in there being 10-20% amber trichomes on most plants and 98-100% brown pistils will coincide with about 20-30% amber trichomes on most plants. This is why the pistil colour method is reliable and I must say, the easiest way of determining harvest timing. It is certainly the best indicator of plant health and it is plant health that determines trichome cannabinoid composition, not trichome colour on its own. Let your preferred type of effect guide your harvest timing! I have been using this "pistil colour method" for 35+ years and swear by its results. Besides, I am yet to meet anyone who can pick the difference between 20% and 30% amber without looking at the plants! Hope this helps, Organoman.

Full internet of answers even if you put your question straight into Google search ... Good luck in harvesting and enjoy smoking !

Yes, that is the most common method. Keep in mind that EVERY plant and strain is different. Clear is not yet ripe, cloudy is ripe, amber is over ripe/declining. I use a 60x hand held microscope (about CAD) that I found on Amazon. There are also digital ones with their own screen or you can pair with you phone. I prefer the simplicity of just putting the microscope to my eye and looking versus keeping a battery charged and my phone's Bluetooth turned on. Since the trichomes don't all change at the same rate I use a little judgement to pick the harvest time. If I've got few clears and mostly cloudy I'll harvest. Usually though I see more clears than I want and will wait until I have 10-30% ambers and fewer clear trichomes. The more ambers the more couch lock, relaxing the high. The more cloudy trichomes the more uplifting and happy the high.