What is this and is it dangerous?

A customer has a question and I hope we can get some opinions on it, thanks

Dr. Sir, regarding the previous message I’m using 2000 wtt LED. 2 of them in a 5 x 8 tent. Maybe to much heat?? I have a huge ventilation fan and monitor heat. We live in Hawaii and it’s always hot! But I keep tent 75 to 92 degrees. I water according to plant. But these spots keep pooping up!! What is this and is it dangerous??
Picture of one light off while I prune debris.
I purchase all my seeds from you.
I can’t find anyone with a real answer. To many cooks in the kitchen per day. However I trust YOU

Not much info to go on. I doubt its caused by the lights. Those are really only around 400w each. I would say it is a ph problem. Slightly out of range or too much fluctuation. But it’s hard to say with no info on temps,rh, soil, or nute feeding.


I feed them once weekly. I average the temp during the day at around 90 degrees. Ph is about 6.5


Temp might be just a little bit high. What is the humidity?

I monitor humidity and it averaging about 60%.

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If my girls get over 80+° i freak! I keep temps between 70° - 79°. Believe your too hot.


Absolutely too hot. You can put some ice on the soil to cool the roots. Those tips also look like light burn. Led lights don’t get hot but they can surely burn your plants if too close. U may b shocked to hear this but u probably don’t have enough light in that size space. They say 2000 but they aren’t even close. U need 50 true w per sq ft. So u need 2000 real watts. With all that said your plant looks awesome from the overall pic.

And a side note. So jealous of Hawaii.


30-40 w sqft for cobs is about the magic number

He’s using led

True I thought I was in the other thread my bad. Even still without the option of dimming. I’d stick around that number

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It always warm here. Unless I use AC I’m not sure how to fix this. Lots of ventilation. Huge fans

I’m new… cobs?

Can I prune them? Makes me sad to cut back but what if I cut about 6 inches off tops. Their in their pre flowering stage. Like I do 12 hrs of darkness and 12 of light starting about two weeks ago. Plants are 9 weeks old.
I’m obviously new and appreciate the information.

Sorry I was in a couple threads, COBS are a type of LED. means Chip on Board. Yours are just LED Diodes but for a 5x8 tent you have 40sqft which you want about 30-40 watts of power per square footage. So at minimum, if you’re trying to fill your tent you should at least have 1 more 2000w(400 real watts) of power. I wouldn’t worry about pruning the tops. That’s where your flowers are going to be the biggest and most potent. If anything you can prune the bottom 3rd of the plant or if any leaves are in shade.

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@dbrn32 might be able to help if it’s a light/heat issue.

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Thanks for tag @AnneBonny

90 is hot, how cool are your lights out temps? People grow dank weed in 100+ degree weather outdoors all the time, what they usually don’t have is 100 during the day and 60 at night repeatedly. For that reason, I don’t think I would do anything drastic like ice down the root ball. It’s not good that they’re hot, but rapidly dropping the temp isn’t going to make the situation any better.

You said you’re running fans? Do you have a dedicated exhaust fan removing air from the space, as well as an intake bringing fresh air into the space? If so, what are ambient temps of the area the intake air comes from?


About 86 degrees

Hey, I have a commercial exhaust fan. It circlarrs a lot of air!!!
I moved 4 of the ten plants to another grow tent as I realized I was over crowded.
I spent a lot of$$$ on these lights but want what’s best. Can you recommend a light? My tent is 5x5x8

Thank you

How often you feed your plants? Any special brands I can get my hands on in US??

Thank u

Day time temps are alway same here… it sucks… I prefer seasons.
About 86 everyday and 70 at night. Great exhaust fans running.