My plant:
10 weeks of Vegetative state, issue with fan leaves for the past 5 weeks
Currently in it’s first week of flowering 11/6/2019
I’ve been stressing about this and I just don’t know how to fix it.
My issue:
All new fan leaves start yellowing and then develop brown spots and generally speaking look very unhealthy. I’ve been pruning them off but it’s unsustainable. Lower leaves appear to be more affected. The entire plant went through a yellowing phase 3-4 weeks ago. It looks healthy but there was a very noticeable change in colour (could be strain related but thought it could be relevant). Recently I have been finding blackened tips on some of the lower leaves as well.
My guesses: Based on research, Zinc seems to be a likely culprit. But the symptoms are so similar for so many different issues I"m afraid of misdiagnosing. I also read zinc toxicity is very real and that I could kill my plant. ANY help would be GREATLY appreciated.
Medium: Soil (pro mix premium all purpose soil)
pH: 6.05 (I have a cheap amazon reader, it could be slightly off)
Water pH: Tap water is around 7.5-7.9 here (using the same reader)
Strain: Amnesia Haze
PPM: N/A
Light: 600w HPS approx 35" above plant
Temperature: 80F during 12 hours on, 72F 12 hours off
5 Gallon fabric pot
Hard to tell from those pictures but at any rate you should think about going back into veg. until problem is fixed and then back into flower. Have you given her any nutes? I would also be checking for bugs.
They are looking hungry.
What are you using to feed them?
Lighter green shows hungry for nitrogen
Brown spots show calcium deficiency or start of phosphorus deficiency
The purpling in centers of Leaf could also be showing N def as plant could be pulling N from fan leaves showing the slight purpling or could also be P issue.
I doubt there is a Zinc issue but ya never know.
Your target PH should be around 6.5 in the peat based pro mix.
A range of 6.3-6.7 or so is fine but at 6.05 the PH will cause the plant to not be able to uptake calcium. How are you using the PH meter? Is the 6.05 your input PH or is that reading from run off water?
Also like mentioned earlier you may want to consider putting lights back to 18/6 until you remedy the issues as you want (need) healthy plants for flower as that’s when the real “stresses” start where the plant goes into overdrive and if it doesn’t have the right conditions any issues will be multiplied etc.
Thanks for all the advice. I just checked my fertilizer bag, and it’s actually Pro Mix Premium Organic Moisture mix. The mix itself doesn’t claim to maintain a certain range of pH. I’m going to go buy some distilled water and re calibrate my pH meter because I have a sneaky suspicion that you’re right and that I"m a little low. I"ll see if I can push it up to 6.5.
