Sureshot2
Well-Known Member
Hey all, so I built a COB fixture using 8x citi 1212 3500k 90cri's for my 4x2' tent. The lights at the time were being driven at ~50-52 watts each and the fixture has been roughly 10-12" from the canopy for most of the grow. At around week four or so I started noticing some rusty spots on the leaves directly under the lights, along with a small of amount of twisting/deforming. I initially thought this might be a cal or mag issue and increased the amount of calmag in my RO water to around 200ppm per gallon, but this didn't seem to help at all. By week 5 the rusty spots starting turning into leaf tips getting brown and crispy, eventually moving down the whole leaf, as well as many leaves starting to canoe on a different strain in the tent.
I have been told differing thoughts by various people, some saying it was a temperature/rh issue (VPD??), some saying the lights were too close/needed to be dimmed and others saying it was a lockout issue (I don't think this is the case). Before this grow I was using T5's using the exact same regimen/environment with no issues which is as follows:
3 site RWDC
pH ~5.7-6.1
PPM during veg ~550-600, flower ~650-750 (0.5 scale)
Nutes are GH Flora Duo + Calmag (using RO water)
Additives include Floralicious+, Mammoth P, KoolBloom (Liquid from weeks 3-7, dry from 8-9)
Res is non sterile using Heisenberg based tea
Temps on average are around 75-80f, RH is around 45-50%.
Res gets changed every 2 weeks.
After some suggestions from a friend I dimmed the lights from 50-52W per/sqft to around 40 during week 6, but obviously at this point damage was already done. There was also a point between week 2-4 where the temps were hitting 85-90 on some days due to some warm weather and AC being out of service. At this point I'm not worried about this crop since I'm already in week 8, but I'd like to narrow down what the exact problem was during this grow so I can avoid these issues on the next grow. It does seem like the damage hasn't gotten any worse after dimming the lights, but this could just be a coincidence?
Here's some pictures from a week or so ago:
Sorry if there's any information missing, I'm pretty tired right now. I can grab some more pictures if needed tonight.
I have been told differing thoughts by various people, some saying it was a temperature/rh issue (VPD??), some saying the lights were too close/needed to be dimmed and others saying it was a lockout issue (I don't think this is the case). Before this grow I was using T5's using the exact same regimen/environment with no issues which is as follows:
3 site RWDC
pH ~5.7-6.1
PPM during veg ~550-600, flower ~650-750 (0.5 scale)
Nutes are GH Flora Duo + Calmag (using RO water)
Additives include Floralicious+, Mammoth P, KoolBloom (Liquid from weeks 3-7, dry from 8-9)
Res is non sterile using Heisenberg based tea
Temps on average are around 75-80f, RH is around 45-50%.
Res gets changed every 2 weeks.
After some suggestions from a friend I dimmed the lights from 50-52W per/sqft to around 40 during week 6, but obviously at this point damage was already done. There was also a point between week 2-4 where the temps were hitting 85-90 on some days due to some warm weather and AC being out of service. At this point I'm not worried about this crop since I'm already in week 8, but I'd like to narrow down what the exact problem was during this grow so I can avoid these issues on the next grow. It does seem like the damage hasn't gotten any worse after dimming the lights, but this could just be a coincidence?
Here's some pictures from a week or so ago:
Sorry if there's any information missing, I'm pretty tired right now. I can grab some more pictures if needed tonight.