Hey y’all, I’ve noticed a pattern in some of my grows that I was basically chalking up to light stress. Mainly I did thought this because it affects the upper growth almost exclusively, and tends to get better when I raise the light.
However, I’ve decided that I actually have no idea what’s going on
- Bright Yellow tips on upper leaves
- Bright Yellow margins on upper leaves
- Shows up after 5-7 weeks flowering
Here is one plant about 6 weeks into flower:
One week later:
Here are two other plants in the tent that demonstrate more clearly:
Notice how below the second node, the leaves are 100% unaffected:
Here is previous plant I grew that really got out of hand:
Here are some things that I do that are not normal…
I use pool shock, I used to measure but now just eye ball it. The plant that got out of hand was actually done with dutch master zone. I did find one article suggesting chlorine tox shows up as yellowing tips and margins. However I did measure when using Zone and Zone uses chloramine mostly and that plant had the worst case.
I water my 4 inch rockwool cubes 7 times a day including for 1 minute in the middle of the night. These guys dry out very fast.
I stopped using circulation fans and rely completely on my exhaust fan
I never go above 1.0 EC in the rez, and my tap water makes up .3EC
I can’t break 40k lux, and usually have to limp to the finish at about 30k lux at canopy. This doesn’t seem normal, when I talked to other LED users they usually measure 50k minimum lux.
I’m using DynaGro brand nutrients.
The plant that got out of hand was done using vero COBs, the others with EB strips
My plan for my next grow is going back to 6 inch rockwool cubes, adding back circulation fans, going back to GH 3 part and using minimal H202 if my rez starts to smell.
If that doesn’t seem to get rid of the problem I guess I will have to try an HPS as I am just stumped with wtf could be going on…