Can anyone tell me what could possibly cause this? I'm in coco 5th week into flowering and I have a hand full of leaves getting this way. I'm using the canna line and everything is in check (to the best of my knowledge). And I can't seem to find a relatable picture or diagnosis when searching.
Phosphorous deficiency is my wild guess. Don't know about them being crispy but they definitely have the look. The only other thing I would say is heat stress or just stress in general but typically you'd see purple in stem if that was the case.
Nitrogen toxicity... just a guess without additional info. Overly dark green color with burnt edges indicative of N burn.
[quote name="Bootheel Bandit" post="19230488" timestamp="1388033588"]Phosphorous deficiency is my wild guess. Don't know about them being crispy but they definitely have the look. The only other thing I would say is heat stress or just stress in general but typically you'd see purple in stem if that was the case.[/quote] there is some purple in the stems on my plant here
[quote name="mmman" post="19231589" timestamp="1388066249"]Nitrogen toxicity... just a guess without additional info. Overly dark green color with burnt edges indicative of N burn.[/quote] and this is occurring on lower and middle leaves. So perhaps this could be?
If there's purple in the stems then id say stress. Have your temps, ph, or humidity been out of control any? If you hadn't had nute problems and your 5 weeks into flower then I doubt it's that now but it's always nice to have a TDS meter around.
Temps are perfect. Ph going in is 5.8. And humidity is very low, under 20% lately. And I do have a meter and the last feed was at 1.8ec using calmag, coco a&b, boost, and pk 13/14
Yeah I'm as confused as you. I even went over past notes from problems I've had and can't pin it down for you. If there's more progression then I'd have to say start cutting back on the nutes a tad. Could be a sensitive strain. Strange that far into flowering though and everything you say doesn't point to any obvious solutions. Good luck bro and if you find out what's up with it update us.