This plant is a Northern Lights auto growing in coco/perlite, 5-gallon fabric pot, General Hydro Flora nutes, She is at day 75 overall, and day 48 of flowering. I’m feeding twice a day at EC 1.3-1.4, getting lots of runoff at an EC not too much higher than the input (1.5 - 1.6). Temp is 70-75, RH is 45 - 60 % (varying on different days)
She started showing this curling issue a few days ago.
She’s pretty healthy overall, except for this new issue. It’s only happening at the top of the plant, so maybe too much light? But the top of the canopy is 15" from the light, not too far from the 18" distance recommended by AC Infinity.
Looking at your leaves, yes. Definitely the light, the leaf tips are burnt, nute overload. Even the lower leaf tips are curling up. Mabey we can get @OGIncognito to weigh in, he’s a coco guru. He’s my weedro….hero in weed! Lol
Actually, @OGIncognito told me that my EC was too low, not too high. He recommended 1.6 - 2.0. I had been at 1.2-1.3 (which my feeding schedule indicated) and I went up to 1.4 a few days ago.
I turned the light down from 100% to 80%, I’ll see if that helps (but I guess the burned/curled leaves won’t recover - but that may stop it from progressing to more and more leaves.
It’s weird, but I have another Northern Lights auto growing in another tent, a week ahead of this one, and it looks fine - no curling or tip burn, and it has been getting the same nutes. And I think the light in the other tent is stronger, not weaker. I’ve been avoiding having to measure the PPFD/DLI, but maybe I have to start doing that.
Thanks for the tag @Growdoc. I will say that from reading your numbers and the liberal run off it could be lighting intensity. Are you checking the run off PH? Fertigating twice a day with liberal run off keeps a healthy root zone, my assumption would be PH, heat or the lighting intensity. Are you using a meter to check the PPFD or DLI. What’s the environmental conditions like , temps/RH
Some plants just take more than others. If OG told you to increase, listen to him, he is up on the coco, I’m a Promix guy, I wasn’t thinking about coco washing old nutes out every feeding, coco doesn’t build up salts as bad as other mediums. I stand by the light burn though, hope that solves your issue, as you said, leaves don’t recover after being damaged. Good luck!
@OGIncognito Thanks for your suggestions - Light intensity could well be the problem - I have not ben measuring PPFD/DLI, should probably start. Temps and RH are good I think - 70-75F, 45-60 RH (on different days).
We recently discussed pH in a different thread about one of my OG Kush plants - The runoff pH is about 5.1-5.3, 1.0 lower than the input, in all 4 of my current plants, no matter what I do, and I’m not sure how to fix it.
Thanks for your comments. The plant looks pretty good overall, except for the top few colas which have these curled, dry leaves. It looks like the newer leaves emerging near the tips of the colas are healthier - but maybe they just haven’t had time to be affected like the first ones to curl?
This is my second grow, and I’m using General Hydro Flora nutes. In my first grow, last spring/summer, I used Fox Farm nutes (at about EC 1.2 in flowering) and I didn’t have any of these problems. But they are also different strains this time, and lower humidity in general.
Very odd on the PH coming out low, range for coco should be 5.8-6.2, I try to maintain 6.0. You may have to do a reset flush, at some point the coco must have went dry and you could possibly have some salt build up that’s tanking the PH
