LED canopy temps

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Blackdog is a manufacturer of Backdog Leds.

"There is a prevailing consensus that 75 °F is the ideal ambient temperature to grow Cannabis under HPS lighting without CO2 supplementation. This experimental result indicates that an 84 °F ambient air temperature is required to achieve the same optimal leaf surface temperatures when using plant-optimized LED lighting-- and that a 75 °F ambient air temperature with LED lighting would not achieve optimal leaf surface temperatures, slowing metabolic rates and leaf and flower production."

Here is a link goes into indepth detail about leaf surface temperature, lots of pics, looks legit.

https://www.blackdogled.com/lst/

 

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Experimental Conclusions

From the evidence we collected, it is apparent that ambient air temperature needs to be higher for plants grown under plant-optimized LED grow lights than for plants grown under HPS, MH, fluorescent or even white LED lighting to maintain the same leaf surface temperature, and hence the same potential metabolic rate. How much higher seems to be dependent on the physiology of the plant, which can vary significantly between species, somewhat among varieties, and perhaps even between individuals. However, the results for the majority of our test plants indicate that raising ambient air temperature approximately 9 °F to 10 °F results in an equivalent leaf surface temperature compared to growing the plant under high-power HPS and MH lights.

 

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It goes on to say that depending on the amount of "usable" light determines how much the plant heats up..The more inefficient the lighting, the higher the leaf temps of the plants.

 

[1lildog]

I burned mine at 93 people...toasty. Look at Hamster's grow, he wasn't running 85... But since Black dog says it is the way to go, well then..... Who is black dog.. and why do i care what he says? I grow led, hammy grows led, PJ grows led, we are doing ok with out that bad advice.

BD is an expensive light made in CO. with a lifetime warranty. They are the ONLY one I've seen with decent hangers for led's, instead of cables. Cables don't allow for much height.

 

[cleanbuds]

With my LED anything over 85 was instantly damaging. It depends on the strain though ... my sativa took 80-85 fairly well but the indica hybrid wouldn't tolerate anything over 83. At those temps the leaves were drooping and not growing well.

I could see how because the LED produces no heat that the plants may in some way desire heat from the light, like the sun does, but these plants just can't physically survive over 85. I'd still shoot for 70-82 and nothing over 82 unless you're sure (I have a friend who grows at 80-86 no problems but it's the strain and his technique that works for him).

 

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what type of led you using cleanbuds?

 

[Kraven]

I burned mine at 93 people...toasty. Look at Hamster's grow, he wasn't running 85... But since Black dog says it is the way to go, well then..... Who is black dog.. and why do i care what he says? I grow led, hammy grows led, PJ grows led, we are doing ok with out that bad advice.

I agree, if peeps who are very experienced growers and are using LED's and that's what I wanted to learn about. Two ears...one mouth we are built to listen. My 2 cents.

 

[yooper420]

Have 6 grows under my LED`s. Temps have gotten into the 90`s during the summer. The girls did not really like it, but they survived, with no major problems. Believe air exchange and movement was the saving grace.

 

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Sorry that im bringing this thread back..

But do any of you guys who use HID lighting have access to a temperature gun? If so it would be nice to know the surface temps of your canopy, in relation to your ambient air temperature.


Currently I have 76-77 Leaf surface temps
Ambient temp is at 80'

 

[Dr. Green Fang]

Cables don't allow for much height.

They do if you do it properly :aok:

At first, I was like "where'd all my headroom go?!?!" ... then I doubled up the wire and cut the height they took up in half. If you leave the wire hangers at their like 2 foot length, yep they are quite a bit too long for flowering. Double it up or even triple it up. Not only does this give you more inches of height but you strengthen the cable being used. :aok:

 

[Kraven]

I don't us LED's so maybe my input is not relevant, but I'll back my 40 years of knowledge against a new fanged idea anytime. When you start talking spectrum and wave length distance between white light and UVa, UVb then you really need to go back to the basic chemistry of photosynthesis and realize you can only reach a point of diminishing returns. Additional heat energy has to be dissipated by the plant, in turn that causes stress and takes away from the biological process that are happening during the light cycle. By putting theses processes behind it also affects the krebs cycle therefore if you leave the sweet spot of 70-74F lights on your simply going to take away from your result. See this is where the problems come in, it will be so miniscule that the layperson will never know the difference, hype for the sake of hype does not grow better plants but it does sell expensive equipment when companies are trying to differentiate themselves to get market advantage.

 

[sopappy]

The one thing I took away from my LED literature.... Humidity over 80% VOIDS your warranty.

 

[P Jammers]

I read this thread, and I LOL'ed.

I'll also add if you have a grow light that is subject to humidity then you don't own a grow light.

 

[WeedHopper]

Sounds like a load of bull. My Flower tent runs cooler now with LED's and I don't have to keep my tent temps up in the mid 80's to have success.

Thanks for pointing that out Hammy,,cause it goes against everything ive heard Good about LEDS.And To say that your tent gets hotter with LEDS then Hps just makes no sense. Then again i have never grown with Leds. I have with T5s,, and i didnt have that much of a heat problem with them.

 

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Yo, PJ! Just wanted to say happy 420 post!!! :vap_bong__emoticon:

 

[sopappy]

I read this thread, and I LOL'ed.

I'll also add if you have a grow light that is subject to humidity then you don't own a grow light.

My apologies, P Jammers

 

[Dr. Green Fang]

Easy mate .. spraying direct liquid on an HPS bulb, and moisture in a tent are 2 entirely different cans to open.

I'm taking no sides here, just saying.

 

[sopappy]

I'm not sure about that, Doc, especially in a tent..... he's telling you humidity doesn't matter, I lost him there. I say it matters. Keep the tent (or the room) at 80 RH or less is all I'm saying (because I RTFM)

 

[Dr. Green Fang]

lol... I'm just saying about the direct spray vs just moisture thing.

Don't worry, I keep my RH down Thanks for the heads up though :aok:

 

[sopappy]

I know you are on the ball, Fang.... I'm just tryIng to suck that PJ guy in to my grow thread