My second grow:
Photoperiod feminized plants in coco/perlite, I am supposed to be about 2–3 weeks from harvest, but ive been dealing with an unresolved issue for 2–3 weeks. I suspected pH issues, then cold stress caused by running an AC and dehumidifier 24/7 to keep humidity at 40–50% in a very humid environment. Temperatures dropped to around 16°C, later adjusted to 19–22°C, but growth is still slow and leaves are showing discoloration and drying.
I lost my previous grow lost to bud rot & would really appreciate some advice to prevent losing this one as well.
Thats looking good in there, you're getting close to the finish! Some strains take on "fall colors" in their fan leaves as the plant is winding down. Probably not 100% accurate but the plants have what's called anthocyanins, some a lot more than others and you see it in the slight blush appearance in stems sometimes. So their production is kicked in when temps get lower, I grow outdoors and the turning point seems to be about 60° and lower. Then on top of that, the plants stop giving energy to the fan leaves and they focus more on the flowers, so the plants begin to take on a natural fade.
A natural fade starts at the lowest leaves and works it's way up, usually two nodes shifting at a time upward and it's a slow process, thats how you distinguish a fade from a deficiency. Color wise, they will lose chlorophyll so they may appear lighter or yellower, but leaves with the anthocyanins won't look it became they're holding that color instead of the green.
All this to reel you it looks good in there, the color shift has nothing to do with bud rot and while it is a deficiency of sports , it's not the kind you want to try and correct.
I do want to mention something though... that leaf you're holding with the red edges and I want to try and interpret it for you. The blotchy discoloration is likely normal, that is something I've seen when there was a sudden onset of cold and the anthocyanins dont fill in the color evenly... maybe there wasn't a uniform leaf temperature??? Anyways, that to me looks normal. But it also has a burnt edges appearance, and that's usually a sign that it got a hot dose of nitrogen at a level it shouldn't have gotten and at a time it shouldn't have gotten it. This can also trigger your leaves that changed color from anthocyanins to look exceptionally dark, even black but genetics are in play too. So I'm thinking maybe you slipped some nitrogen in there and it wasn't a bad call entirely... it wasn't toxic levels and it has held on to color for the finish, and doesn't look like it affected bud development.
So for your next run, I would say do exactly what you did this run, but when you do that N supplemental feed, maybe just back off the dose a smidge. You'll wind up with more yellow at the finish but it will be natural.
Edit: Sounds like you noticed it's not stinking up like you think it should. That also tracks with excess nitrogen.
