We covered this topic very thoroughly recently. There is no way to be absolutely sure without being able to peek into the trichomes. Get a jeweler’s loupe or high powered hand held magnifying glass, they are not expensive, not uncommon nor hard to find and it will be well worth it to you to get the most out of your crop.
The way it was done traditionally by native peoples with their landrace strains, before “microscopes”, was to judge by watching the pistils/hairs. And then depending on their individual traditions and what was known of their specific strain, they would harvest anywhere from when around 75% to as much as 100% of the hairs to have browned, and/or even a traditional length of time after 100% of the hairs have browned. But this was with specific stable landrace strains they had been growing in their culture for numerous generations, secrets or well known traditions passed down from parents to children for maybe millennia.
Modern Hybrid strains don’t have much in common with many of these traditional strains, especially as far as their time-frames are concerned and that information would be pretty much irrelevant to you now. Even if you had a traditional landrace and knew all the traditional knowledge passed down by the native creators of that strain, it would still not necessarily be helpful unless you could duplicate the same environmental conditions – elevation, latitude and local seasonal conditions – to be able to expect the same results.
And so again, the only way to be absolutely certain is to be able to peek into those trichomes, or maybe wait until about 100% of the hairs have browned and then make adjustment depending on your preferences, of harvesting a little sooner or a little later with the same strain, next time.
Check out the link below for more detailed thoughts on the percentage of coloring of the trichomes.
Did you harvest? His is my first grow. I’m using feminized plants in pots outdoors. They look a little more mature than the pictures shown. I was going to wait for the white to turn red/brown on about 75% of the flower. Care to share your experience?
It’s been a bit since I’ve been on here sorry for the lag lol but here’s an update. I have not harvested I just let her be but now I’m starting to get tiny tiny caterpillars every now and again a friend said I should harvest since it’s so close and before they get worse should I???