Vero 29 Burn compared to Cree CXB3590

If vero 29 3500 80cri cause bleaching and leaf burn at @30inches, would it be safe to expect the same burn from Cree CXB3590 COBBS???

I've read that a lot of people get burn/bleaching with Veros. I have not seen anything about the Cree cobs though. Looking for something that won't burn at 24 inches.

I think its genetics dependant aswell. I have had my plants grow into my 3590's , no bleaching. Just wierd growth.

3LitGrav said:

If vero 29 3500 80cri cause bleaching and leaf burn at @30inches, would it be safe to expect the same burn from Cree CXB3590 COBBS???

I've read that a lot of people get burn/bleaching with Veros. I have not seen anything about the Cree cobs though. Looking for something that won't burn at 24 inches.

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Yes.

I suspect that people have light bleaching issues due to their nutrients being on the low side of iron. I haven't really done much experimentation with this though because I don't want to drop my iron from 5ppm to see what happens.

I've never had light bleaching issues before. It just burns.

churchhaze said:

I suspect that people have light bleaching issues due to their nutrients being on the low side of iron. I haven't really done much experimentation with this though because I don't want to drop my iron from 5ppm to see what happens.

I've never had light bleaching issues before. It just burns.

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Try Megacrop….One nute and done.

The Vero 29's are causing burning all over. Some bottom leaves while top are fine. The burn seems random, but definitely light burn not nutes... would changing to to the cxb3590 stop burning?

3LitGrav said:

The Vero 29's are causing burning all over. Some bottom leaves while top are fine. The burn seems random, but definitely light burn not nutes... would changing to to the cxb3590 stop burning?

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Not sure why you insist it's definitely light burn, especially when the tops are fine but bottom is not.

If you provide information on your feed schedule (brands, amounts, frequency and age of plant) we could rule that out.

PH issues can also cause similar symptoms. Some nutrient brands don't need PH adjustment, some definitely do. If you're not sure you should invest in a PH pen or start asking around about your specific fertilizer.

Pathogens like root rot can cause similar symptoms.

Regular nutes in a high coir substrate can cause deficiencies without some added cal/mag that could look similar to burn. I use a 50/50 peat/coir mix and have to use cal/mag at 4ml/gallon or I will have deficiency symptoms. This has proven true across various strains. In DWC added cal/mag is not necessary.

There's no critical difference between Veros and CXBs and other common light sources. Even if you had plants less than 2 weeks from seed I wouldn't suspect Veros 30 inches from them to be the problem. But, if you give us more info we can rule that out too. How many Vero 29s, how many watts each and the size space they're being used in. I or someone else can estimate the light intensity and let you know if it's a concern.

churchhaze said:

I suspect that people have light bleaching issues due to their nutrients being on the low side of iron. I haven't really done much experimentation with this though because I don't want to drop my iron from 5ppm to see what happens.

I've never had light bleaching issues before. It just burns.

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Take one for the team Church

I've had bleaching a few times, Vero 18s at nominal. A bud would be directly under the emitter and it would grow to within 2-3 inches. I suspect the burn is more about transpiration failure due to heat/airflow/RH issues while the bleach is more about photon overload. 2-3 inches directly under those Vero 18s the PPFD is about 5500!

Rahz said:

Not sure why you insist it's definitely light burn, especially when the tops are fine but bottom is not.

If you provide information on your feed schedule (brands, amounts, frequency and age of plant) we could rule that out.

PH issues can also cause similar symptoms. Some nutrient brands don't need PH adjustment, some definitely do. If you're not sure you should invest in a PH pen or start asking around about your specific fertilizer.

Pathogens like root rot can cause similar symptoms.

Regular nutes in a high coir substrate can cause deficiencies without some added cal/mag that could look similar to burn. I use a 50/50 peat/coir mix and have to use cal/mag at 4ml/gallon or I will have deficiency symptoms. This has proven true across various strains. In DWC added cal/mag is not necessary.

There's no critical difference between Veros and CXBs and other common light sources. Even if you had plants less than 2 weeks from seed I wouldn't suspect Veros 30 inches from them to be the problem. But, if you give us more info we can rule that out too. How many Vero 29s, how many watts each and the size space they're being used in. I or someone else can estimate the light intensity and let you know if it's a concern.

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Ever try Megacrop ?

This burning only happens under my veros. Everything that is under different lighting does not have the issue. I moved a perfectly healthy green plant under the vero for a few days to see if the burning would start, and it did. Some parts of the plants are 24 inches, some 30 inches from the lights.

6 vero cobs in this fixture: ANJEET 1200w full spectrum cob led system panel

(I have two fixtures in a 5x2.5x7 tent)

I ph and ppm my water every time.
Fox farms ocean farms soil w/coco and perlite.
RO water.
Fox farms nutrient line including beastie bloomz, cha ching and open sesame. Cal mag, silica, hydroguard.

I never had these problems until i added the veros. I have seen posts from others saying their veros burned their plants, and many photos of the same type of burn from vero users who didnt consider the lights to be an issue.

This isnt a brand new issue either. Ive gone through 2 grows while battling this! Now i am working on number 3. I tried a few different things before addressing the lights-- flushing the soil in case of nute burn, watering at very light feeding, increasing calmag, etc, etc.

Took a photo before lights on, ill post more after they are on. This is what it looks like:

3LitGrav said:

This burning only happens under my veros. Everything that is under different lighting does not have the issue. I moved a perfectly healthy green plant under the vero for a few days to see if the burning would start, and it did. Some parts of the plants are 24 inches, some 30 inches from the lights.

6 vero cobs in this fixture: ANJEET 1200w full spectrum cob led system panel

(I have two fixtures in a 5x2.5x7 tent)

I ph and ppm my water every time.
Fox farms ocean farms soil w/coco and perlite.
RO water.
Fox farms nutrient line including beastie bloomz, cha ching and open sesame. Cal mag, silica, hydroguard.

I never had these problems until i added the veros. I have seen posts from others saying their veros burned their plants, and many photos of the same type of burn from vero users who didnt consider the lights to be an issue.

This isnt a brand new issue either. Ive gone through 2 grows while battling this! Now i am working on number 3. I tried a few different things before addressing the lights-- flushing the soil in case of nute burn, watering at very light feeding, increasing calmag, etc, etc.

Took a photo before lights on, ill post more after they are on. This is what it looks like:

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my 2c.
Pics don't look like light burn.
Are you using all 3 fox farm trio bottles plus beastie bloomz, cha ching and open sesame. Cal mag, silica, hydroguard, and a flush.
"Less Is More" with soil growing.
It doesn't look like you are following that theory, looks more like a mad scientist at work lol.
More like a nutrient related issue to me.
Good Luck!

Haha, madscientist mixtures!

No, I don't use all at the same time haha.
My veg tent is perfect. Healthy green, no burns, beautiful plants. Simple galaxy hydro blurple led for that tent.

After 2-3 weeks in the flower tent (VERO) is when the burn shows up.

Feeding looks like this:
1 gallon r/o water
3-4 cc's calmag
2 cc's silica blast
2 cc's hydroguard
2 tbsp FF big bloom
2-3 tsp tiger Bloom
(and sometimes add 1/4 tsp of Beastie blooms/cha ching/open ses, but this is only done 1x every 2 or 3 weeks according to the stage of flower they are in)
Ph'd to 6.2 - 6.4

To me it looks like a phosphorous issue, but I've addressed the nutrients --- and the problem continues. Not only continues, but starts after a couple of weeks on any plant I put under those lights.



THIS post is what directed me to the lighting issue:

https://www.rollitup.org/t/vero-cob-led-causing-light-stress.907578/



In that thread it shows what the leaves look like at the very beginning of the burn. My plants are starting exactly the same way, then progressing.
(This photo is from the post mentioned above, not my photo)

I have blasted my plants with 2,000Umols for weeks @75F.

No bleeching, just stunted wierd growth.

Well, I'll defer to the others who know about light issues.
Only thing I would say is if it starts in your flower room and your veg tent is great. If it is not the light causing the problem what else could it be?
You will evolve in time believe me. My thoughts on fertilizers have changed many times over the years.
This is one example of many plants I have grown in ffof. This one like most of my ffof grows was water only up to this point.
I took this pic because I wanted a pic of the variegated leaf which is cool, I have a ton of other examples.
Less is more.
Good Luck!

That lamp doesn't use Vero emitters. It may contain (some) Bridgelux diodes but they're not Veros. With some heavy guesswork (600w output @ 30% efficiency and 4.65 umol/j in 12 sq/ft of space) I'm estimating the PPFD in your tent to be about 750, not expected to burn especially at 30 inches above the plants. The actual readings 30" below the lamps will be lower than 750. I've never used "full spectrum" lamps so I can only comment so much on them, but as far as I know there's nothing about them that would attribute a burn at that light intensity.

Your elemental NPK (not adding in Beastie bloom etc.) is 100/137/152. While the P looks a bit high to me I wouldn't guess it would cause a P toxicity. Adding in 1/4 tsp Beastie Bloom (the other supplements should result in similar numbers) results in 100/209/234. Way more P than necessary but I'm still not sure it would cause a toxicity. I know plants can tolerate a lot of P but I've never used that much so can't comment on the effect, but I do know it's considered high even under high intensity light.

If you're making clones in a water culture there is the possibility of root rot, which Hydroguard will not cure after the fact. I'm not saying it's root rot but it's something to look at if cloning in water. If you are cloning in water and your roots look pristine I wouldn't suspect root rot. If they're looking a bit tan/brown and hoping they recover in the soil that could be an issue.

Your soil is peat based and prone to PH drops so it's possible your starting solution of 6.2-6.4 isn't preventing a slow decline on the PH scale. Plants tend to produce more positive ions and less negative ions as it transitions into flower so it's a reasonable theory to suggest that 6.2-6.4 would be fine in veg but low in flower which would explain why they stay healthy in the veg tent but not the flower tent. I'm not saying you have a PH problem but it's something to look at.

I would continue to ask around but based off all that I would flush the plants and give them a mild nutrient solution with PH of 6.8. Upon resuming a regular nutrient schedule I would keep PH at 6.8 and avoid the use of PK boosters. 100/137/152 doesn't need a P boost. A lot of people will tell you 137 is already P boosted. If I wanted a K boost above 150 I would look at reformulating the nutrients so it doesn't result in higher P.

That's all I got. I can't guarantee that will fix the problem, but my suggestion also entails not focusing on the light and asking questions in a soil oriented forum. I think people using your media and nutrients would be better able to give useful advice. I do think your P is high, especially for -750 PPFD and your PH is probably on the low side after spending a few weeks in the flower tent. Once you get it figured out and the plants are staying healthy, lower those lamps to 15-16" above the canopy. At 30" you're not getting the best out of them.

You're right, that light does not use Veros. I changed them out and installed the Veros myself.
I actually have 3 of these lights. 2 of them I switched to all Vero's and 1 I left with the lights it came with.

I took the Vero light fixtures out of the tent and put in 2 different cobb fixtures for now.


I am going to follow your advice, and drop the Boosters from the mix entirely and up my PH to 6.8 in flower. I'll give them a flush and mild nutrient feeding at 6.8 later today.

This all leads me to think it might be a combination of the light intensity AND the PH being too low to allow proper nutrient delivery.
However, the PH is probably a bigger factor than the light.

What are your temps and RH? I'm not an authority by any stretch of the imagination, but I have become quite convinced that environment is the most important variable when diagnosing problems like this.

Humple said:

What are your temps and RH? I'm not an authority by any stretch of the imagination, but I have become quite convinced that environment is the most important variable when diagnosing problems like this.

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Good Point! Both should be listed. What are they in the veg tent and what are they in the flower room?

Humple said:

What are your temps and RH? I'm not an authority by any stretch of the imagination, but I have become quite convinced that environment is the most important variable when diagnosing problems like this.

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I'm pretty sure along with over feeding any of the three, light, humidity and or temp are increasing his transpiration rate in the flower room and causing at least part of his problem.

Good point guys....

Temp in flower is 79-81. Temp in veg is 77-78
Humidity in flower is usually around 40-44%
PLENTY of airflow-- in, through, and out.

With all your help here, I think the problem is ph is too low (I don't feed every time I water)
.
I have not seen the problem with my other lights. This doesn't mean the problem wasn't there, maybe it just means the signs weren't as prominent.

SO, Feeding at 6.2ph seems to be causing a deficiency in Phosphorus, Calcium, Magnesium and Molybdenum, and by using the Bright Vero Cobs the symptoms show up a lot faster and at a much higher intensity.

I flushed and very lightly fed at 6.8 this afternoon. . . runoff was 6.2

It seems obvious that my feedings at 6.2 were dropping to 5.5 or so, and locking out usability of the P/C/MG/MO.

Hoping to correct and balance this issue, and get my veros back in the tent in the next week or two.