The visual differences in growth between weeks 15 and 17 is that the more mature flowers at the top have stopped growing white pistils and turning them brown, while the lower flowers further from the light are still growing white pistils. In other words, she is working on consistency. Surely, the flowers that have stopped showing any signs of outward growth, are being developed within.
I did a trim job on the top half only. I trimmed only what she had already dried-up and killed off - nothing green.
I took this weeks photo without the benefit of the tent light, as a point of difference. I am surprised at how green she is in the photo, looks a lot more brown to the naked eye, but the photo does not lie.
My week 17 trichome inspection did reveal a row of about 5 baby amber trichomes on the cola. But this is not enough to make me harvest. She should turn brown at harvest time, especially since I am growing organic. I believe that is the natural state, all brown harvest. I have seen flower being harvested surrounded by green foliage. I believe that to be down to powerful chemical nutrients. Also, what you have to be careful of is that the trichomes on yellow (dead) leafs are yellow in color. So as the plant turns all brown the trichome
distinguishing becomes tricky.
As I am only doing every-other-week, postings - I am adding the following update on 9/19/23.
On day 120 (and after extensive research) I changed the photo-period to a 10 hour day to speed-up the process. From what I understand some people mistakenly go back to 18/6 so they can start another plant. This will slow a flowering plant down. The results of switching to a 10 hour day were almost instantaneous. 2 days later - she started turning the remaining green, a dark purple. Still a ways to go but at the increased pace I am expecting a harvest in week 19, 20 at the latest. Of all my experiences growing this is the first time I am seeing a color other than white/brown (fibers) or green. Well pleased.