Light burn or nutrient problem?

[Ezdeezy89]

83-85 temps, same with leaf surface temp. 1000w HPS 24-30 inches from canopy
Always run my flower ppfd around 1200umol with 1400 ppm co2, up to 1500 umol later in flower. I'm 3 weeks in, never had this issue but I can't figure out anything else that it might be. Running about 600ppm drain to waste in coco with about 15% runoff. pH is at 6.0 off slurry test and ppm is the same as it's going in.

Leaves are starting to turn lime towards the upper half
I'm wondering if I should drop the intensity due to light stress. Any opinions would be greatly appreciated.

 

[Cannagar]

83-85 temps, same with leaf surface temp. 1000w HPS 24-30 inches from canopy
Always run my flower ppfd around 1200umol with 1400 ppm co2, up to 1500 umol later in flower. I'm 3 weeks in, never had this issue but I can't figure out anything else that it might be. Running about 600ppm drain to waste in coco with about 15% runoff. pH is at 6.0 off slurry test and ppm is the same as it's going in.

Leaves are starting to turn lime towards the upper half
I'm wondering if I should drop the intensity due to light stress. Any opinions would be greatly appreciated.View attachment 1302579

Without seeing the whole plant it’s hard to diagnose.

 

[Shaded_One]

Light intensity is a prime driver for feed/nutrition so could be both. Lowering the light intensity or increasing feed should tell you in a few days what the answer is especially if this is a new strain to you.

 

[Titleist]

Happening on top growth is one clue. If you notice it on half a leaf where the other half was shaded that's a pretty strong clue. From the pics of the leafs shown it looks exactly like light burn. Leaves get lighter in a striated pattern, after a week or so the light areas die off which is what these leaves appear to be doing. Bleaching, dead spots,serrations appear to be curling. Symptoms of too much light.

Just me, but it seems you run pretty hot there with 1200 umol and 85 degrees without CO2. Are you experiencing slow growth?

 

[Ezdeezy89]

Happening on top growth is one clue. If you notice it on half a leaf where the other half was shaded that's a pretty strong clue. From the pics of the leafs shown it looks exactly like light burn. Leaves get lighter in a striated pattern, after a week or so the light areas die off which is what these leaves appear to be doing. Bleaching, dead spots,serrations appear to be curling. Symptoms of too much light.

Just me, but it seems you run pretty hot there with 1200 umol and 85 degrees without CO2. Are you experiencing slow growth?

Growth is good, I run 1300-1500 ppm co2 depending on which week of flower I'm in. I cooled the room more, raised lights and upped my ppms and they are doing better. Wish I had the time to do them one at a time and see the results of each so I'd know which one was the culprit but it honestly seemed like all 3.

 

[Ezdeezy89]

Light intensity is a prime driver for feed/nutrition so could be both. Lowering the light intensity or increasing feed should tell you in a few days what the answer is especially if this is a new strain to you.

I agree, pretty sure it was a combination. My LEDs are around 900 umol and I've hit every strain I've done with 14-1700 ppm with no issues. Same exact room design with the exception being that these are HPS. Didn't really think that through, especially since the last time I used my hps lights (years ago), I was over 2100ppm on a relatively sensitive strain that's typically prone to nutrient burn. Thanks for the information everyone.