# LED canopy temps



## next (Jan 27, 2015)

Hey guys,

I have some conflicting information about what temps to run my grow tent. With hps/mh it is recommended that optimum temp is between 75-78. But recently I have read that temps need to be higher with an LED grow, due to the non intense heat coming from the light.

"Although, it is commonly agreed that 75 degrees is the perfect ambient  room temperature for hps. LEDs, you have to use 85 degrees because your  canopy stays at 85 degrees with this light."
"We are just talking about how 85 degrees is your optimum temperature  when growing with LEDs, the range being a minimum of 80 degrees and a  maximum of 90 degrees. Above 90 degrees your plants will be stressed,  below 80 degrees they simply wont transpire enough moisture to grow at a fast rate"

Do you guys run your temps in the 70's, or the 80's with your LED's? I was running canopy temps at 78, but recently up'd the temps to about 85. What do you guys do???


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## Rosebud (Jan 27, 2015)

I try to keep my temps under 80. My led's seem to add 7 degrees to the ambient temperature. I think 78 would be better for your plants the 85. That seems too hot.  I have had mine that hot in the summer and they suffered. Just my thoughts.


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## The Hemp Goddess (Jan 27, 2015)

Where did you read that?

I also do not agree.  I can't think of any reasonable reason that the type of lighting you are using should affect the canopy temps you should keep.  By this way of thinking, T5 should be run hotter, too.


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## next (Jan 27, 2015)

Just did a search for "led grow room temp" most results seem to come from the same source. Here are a few links

http://www.dormgrow.com/grow-tips-for-led-grow-lights

http://www.prosourceworldwide.com/how-to-grow-medical-marijuana-using-led-grow-lights/

http://www.bestseedbank.com/how-to-grow-medical-marijuana-using-led-grow-lights/

http://www.truliteled.com/growing-cannabis-with-led-grow-lights/


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## The Hemp Goddess (Jan 27, 2015)

I am not really understanding their logic?  You actually do not want your root zone as hot as your canopy, whether you are growing soil or hydro. 

These 2 sentences do not even make sense to me:  "However, with LEDs, in order for my canopy to be 85 since these lights put off heat my whole room has to be 85 that is the single biggest difference between growing with LEDs and growing with High Pressure Sodium. Although, it is commonly agreed that 75 degrees is the perfect ambient room temperature sodium LEDs, you have to use 85 degrees because your canopy stays at 85 degrees with this light."

IMO, we don't want temps to be 85 anywhere in our tents.  I only went through the one link, but it made my head hurt trying to figure out what they were trying to say.  I also do not know whether I would trust the LED salespeople.


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## Locked (Jan 27, 2015)

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.


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## next (Jan 27, 2015)

Good to know, lots of misleading information out there. I appreciate you guys taking the time time set me straight. I had some purple petioles going on, so I looked up temps again and stumbled upon those sites.. given that I had the purple petioles and those websites recommending the higher temps I almost believed it.


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## techrons78 (Jan 27, 2015)

My led tent is running.  In low to mid 70 and my plants r rocking...im selling my 1k hps im gonna go all led...


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## blowinthatloud (Jan 30, 2015)

My grow room is about 65 with the lights off an 75 or so with the lights on.


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## The Hemp Goddess (Jan 31, 2015)

LOL--my flowering closet is rocking and rolling with a 1000W HPS and 70 degree temps.  I am one of those that needs the heat from an HPS during the winter.  Do keep in mind that the heat can be a good thing if your grow space tends to run cool.  

Yes unfortunately there is still a of lot of misinformation and more unfortunate, a lot of it is greed motivated.  The internet is a great resource, but I also see published things that are not worth the bytes it takes to store them.  LED people still lie about the coverage of their lights.  Salespeople are still trying to sell duct booster fans to go with carbon filters.  People are writing grow books that are filled with misconceptions, misinformation, and downright falsifications.  This is one of the things that make forums so great.  You get the input from a myriad of people who have real experience, not anonymous avaars on a screen or written page that may or may not be true.


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## blowinthatloud (Jan 31, 2015)

I agree totally goddess, some of the info out there is crazy! Lol 
i try to research more then one place an ask alot of questions, i try to find other people or other sources with the same info just to double check myself. Ive ruined complete grows listening to bad info! BtL


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## Gaiant (Jan 31, 2015)

I spoke with Blackdog support earlier have a light coming and was told the same 85 degrees.


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## Joe420Camel (Jan 31, 2015)

I asked the teller @ the bank about investing my money... she mentioned bit-coins.



seriously though...
this is new territory we are all blazing with each new light technology that comes out.
some of the old rules do not apply to LED, LOTS do!

I'm open to the possibility BUT I need to see proof from multiple sources, scientific explanations (that I might not understand) as to why this happens etc.


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## yooper420 (Feb 1, 2015)

Talking about LED`s and best temps to grow in. And the affects of temps, high or low. At least inside you can regulate the temps. Outside, Mother Nature does her job. Try to remember that this is a WEED, that has grown for hundreds, if not thousands of years, without intervention by man. Yes, man has helped our beloved weed reach it`s potential, but it did great by itself. Try to keep my garden room in the 70-80 degree range, don`t always happen though. Outside growers have no way to regulate the temps as inside growers do. My garden room is in the back corner of my garage, up off the floor. Inside measures about 7'x7'x7', use the back half as growing space. Have 2 Advanced Diamond Series 300`s. I do have some heat issues in the summer. 2 passive intake vents and an 8" exhaust fan for warm weather use, 2" squirrel cage blower that I use as an exhaust fan in cold weather. Enough rambling on for now.


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## The Hemp Goddess (Feb 1, 2015)

If that made any kind of sense at all, I would pay some attention to it.  But the links that I read were confusing with a lot of conflicting information and no scientific backup to their assertions that I could find anywhere.  

Also isn't one of the real advantages of LEDs is that they run cooler and allow us to keep our spaces in the 75 degree range without a lot of problems.  I would have to be running space heaters in my space all the time in the winter to get it to 85 degrees....and then what is going to happen to root zones and res temps if running hydro?  It simply does not make any kind of good growing sense at all...


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## yooper420 (Feb 1, 2015)

I grow year round. My garden room is fully insulated. In winter, how hot do you want it ? We can get there. In summer, do have some heat issues, even with LED`s. Right now it`s still 4 degrees BELOW zero out where I live.


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## next (Feb 13, 2015)

From what I understood, the reasoning behind it is that with HID lighting, your plants are subjected to alot more infrared heat. With led's they don't have near the amount of infrared that HID's or the sun puts out, so the increase in ambient temp is to make up for it.


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## yooper420 (Feb 13, 2015)

I`m just a dumb ol` hippie (67) that is completely happy growing his own MJ. Might not be the best, but anyone who`s tried some has not complained. Some even had good things to say. Can it be improved on, in potency and/or yield ? I`m sure it could, but do not think that there is any magic potent to do it with. Try to keep my garden room 75 - 80 with lights on and 60 - 65 with lights off. When all of the techno geeks figure out the baby steps to better MJ, someone please let me know. Until then I`ll kick back and enjoy my home grown.


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## Dman1234 (Feb 13, 2015)

Im not saying im a believer, or even understand why, but there sure is a lot of info on the internet suggesting LED grows should run at a slightly higher temp. But then again the info found on the internet isnt always correct. Just saying this topic is widely discussed.


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## Rosebud (Feb 13, 2015)

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.


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## next (Feb 13, 2015)

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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## next (Feb 13, 2015)

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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## next (Feb 13, 2015)

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.


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## 1lildog (Feb 16, 2015)

Rosebud said:


> 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.


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## cleanbuds (Feb 22, 2015)

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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## next (Feb 25, 2015)

what type of led you using cleanbuds?


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## Kraven (Feb 25, 2015)

Rosebud said:


> 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.


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## yooper420 (Feb 25, 2015)

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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## next (Mar 14, 2015)

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'


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## Dr. Green Fang (Mar 15, 2015)

> 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:


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## Kraven (Mar 15, 2015)

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.


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## sopappy (Mar 15, 2015)

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


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## P Jammers (Mar 15, 2015)

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.


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## WeedHopper (Mar 15, 2015)

Hamster Lewis said:


> 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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## next (Mar 15, 2015)

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


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## sopappy (Mar 15, 2015)

P Jammers said:


> 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


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## Dr. Green Fang (Mar 15, 2015)

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.


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## sopappy (Mar 15, 2015)

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)


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## Dr. Green Fang (Mar 15, 2015)

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:


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## sopappy (Mar 15, 2015)

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


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## P Jammers (Mar 16, 2015)

sopappy said:


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



My comment on moisture was a direct response to the fact a LED light can not be in more than 80% humidity. 

If the light can't handle it, it is garbage.

I'm also laughing at the comments on temps and how they need to be different for LED vs HPS. It's garbage, and I have done more research on the tech then most of the companies that exist right now.

But hey, if you want to challenge me on the subject, take your best shot. Just know that I deal in scientific data, and not what Joe said over at RIP.

BTW not sure what tool goes around spraying bulbs with moisture, but that would be 100% humidity not 80%.


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## next (Mar 16, 2015)

Thanks for your 2 cents PJ, I appreciate you stopping by. I picked up on you laughing at the temp debate, and I do value your opinion, especially considering the work you have done with leds. 

Are saying that the radiant heat that comes from HID's and the sun don't have any relation to the ambient temps?

You can 100% feel the radiant heat under HID's, but not quite so much under LED's. Especially if the LED is for vegging.

Do you have any scientific data by chance that could show me the light so to speak? 

peace


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## P Jammers (Mar 16, 2015)

next said:


> Are saying that the radiant heat that comes from HID's and the sun don't have any relation to the ambient temps?



No, I am not saying anything of the kind. I am stating that you do not need to have a warmer room temperature for LEDs over HID's which was the reason this thread was started, or so the way it read to me. While there is some cause and effect on stomata due to temperatures they are more effected by the amount of CO2 preset in a room. Less CO2 and your leaves will be large, more and the leaves will be smaller. 

Yes HPS puts off more heat, that is one of the several reasons LED's are far better than HPS.

It was also said that LED's are not recommended or warrantied in an RH over 80%, and my other comment was that if you have an LED that can not go over 80% that it is not a real light meaning  it is crap. 

I really can't break it down anymore than that.


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## WeedHopper (Mar 16, 2015)

Thank You PJ. Knew something didnt sound right. Still havent used Leds yet, but im WARMING up to them. Get it;;;;;;;WARMING UP;;;;;, LOL. Sorry im a little buzzed.
:48:


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## Kraven (Mar 16, 2015)

P Jammers said:


> No, I am not saying anything of the kind. I am stating that you do not need to have a warmer room temperature for LEDs over HID's which was the reason this thread was started, or so the way it read to me. While there is some cause and effect on stomata due to temperatures they are more effected by the amount of CO2 preset in a room. Less CO2 and your leaves will be large, less and the leaves will be smaller.
> 
> Yes HPS puts off more heat, that is one of the several reasons LED's are far better than HPS.
> 
> ...



Glad to have your wealth of knowledge at hand PJ, I'm sure as I slowly move into the 21st century with my grows that I will need to mine your vast knowledge. I can see being completely hydro under LED's in my future, it's just gonna take me baby steps to get there. Now if you want to talk guerrilla outdoor grows in bags of dirt hanging from trees....deer likes the weed, then I might be able to set you hip to how it's done, I have only been indoors about ten years now.....so still have a long way to go on the finer points of a successful indoor grow.


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## Dr. Green Fang (Mar 16, 2015)

LOL WH.. you got me on that one.  :aok:


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## Dr. Green Fang (Mar 16, 2015)

Kravenhead said:


> Glad to have your wealth of knowledge at hand PJ, I'm sure as I slowly move into the 21st century with my grows that I will need to mine your vast knowledge. I can see being completely hydro under LED's in my future, it's just gonna take me baby steps to get there. Now if you want to talk guerrilla outdoor grows in bags of dirt hanging from trees....deer likes the weed, then I might be able to set you hip to how it's done, I have only been indoors about ten years now.....so still have a long way to go on the finer points of a successful indoor grow.



Man, I wish my body was younger. See, I'm young but my body isn't lol. I would love to guerilla grow in trees!


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## WeedHopper (Mar 16, 2015)

I gotta million ofem,,,,,,,well,,,,, maybe one or two anyway. He he


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## P Jammers (Mar 16, 2015)

Kravenhead said:


> Glad to have your wealth of knowledge at hand PJ, I'm sure as I slowly move into the 21st century with my grows that I will need to mine your vast knowledge. I can see being completely hydro under LED's in my future, it's just gonna take me baby steps to get there. Now if you want to talk guerrilla outdoor grows in bags of dirt hanging from trees....deer likes the weed, then I might be able to set you hip to how it's done, I have only been indoors about ten years now.....so still have a long way to go on the finer points of a successful indoor grow.


I grew outdoors for years in NorCal. I miss the huge plants, but everything else that went with it, well except for the tequila I don't miss too much. 

Hard work for sure.

Appreciate the kind words.


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## 1lildog (Mar 17, 2015)

Dr. Green Fang said:


> 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:



Yea, I doubled my cables originaly. Still not enough headroom. Tripple the cables, maybe but I think doubling and trippling the cables is a disaster waiting to happen.

Some of the lights contain mounts for the hangers that are NOT located on the corners. Instead they are moved in toward the center. You don't need cables with these. Like on the 2015 mars 5w.


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## Dr. Green Fang (Mar 17, 2015)

> I think doubling and tripling the cables is a disaster waiting to happen.



Sorry mate, but theory stands that when you double up, or more, something like string etc... it only makes it more than double as strong. More pull weight. 

Rough that you're still without headroom. You eliminate your pulley system too ya? I had to bypass mine last night, to give more room for the end of the stretch.


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## Kraven (Mar 17, 2015)

Hey doc throw us a few pic's, want to see how your dealing with limited headroom and led's


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## Dr. Green Fang (Mar 18, 2015)

This is how they look with the wire hangers "doubled up". You could go as far as triple up, but that'd be pretty messy and not fun to do. I would use mechanics wire and make an "X" with them for the hangers. I actually DID do that on day one because those darn wire hangers were SOOOOoooooo long!! After I doubled them up, I was happy. What I'm doing right now to fight my height issue during the stretch, is, I eliminated my pulley system, and hooked right onto the top of the frame. That's as absolutely high as any light should go. It has enough space in the top of the tent to do the "air intake, exhaust" thingie it needs to do   hah 

I'll get a pic tonight. In one tent, I have 2 of the fixtures at the same height and then two others that both vary in height. One of them, I clipped further up the pulley, and the other is hanging from the top bar of the tent. :aok:


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## yooper420 (Mar 18, 2015)

Replaced the cable with light duty chain and hooks, very adjustable now.


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## Dr. Green Fang (Mar 18, 2015)

Kravenhead said:


> Hey doc throw us a few pic's, want to see how your dealing with limited headroom and led's



Some pics of my LED's. Two are at the same height, and the other two are staggered. One of the LED's is as absolutely high as I can get it in a tent now I believe. I want to leave enough space for the light to "breathe". 

In the first picture, the light is hanging normally with the pulley system. 
In the second picture, the light is up on the top hook of the pulley system, and surpassing most of the pulley.
In the third picture, the pulley system is entirely surpassed.
All lights have had the wires doubled, to gain some height. 

View attachment LEDHangersTall (1 of 3).JPG


View attachment LEDHangersTall (2 of 3).JPG


View attachment LEDHangersTall (3 of 3).JPG


View attachment LEDHangersWide (1 of 1).JPG


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## 1lildog (Mar 18, 2015)

It appears to me that much more force than usual is exerted on the bent area of the cables and at the crimps when doubled and tripled. This is what I did instead. 

View attachment SAM_0129.JPG


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## 1lildog (Mar 19, 2015)

Few more.
View attachment SAM_0131.JPG

View attachment SAM_0132.JPG

View attachment SAM_0133.JPG


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## WeedHopper (Mar 19, 2015)

Pretty and Pink


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## next (Mar 19, 2015)

lildog, I see your temp meter reading 79 ontop of the light. Is it warmer or cooler underneath? I would assume slightly warmer, and that would put you in the low 80's. Which is what I have been trying to figure out...


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## 1lildog (Mar 19, 2015)

That meter is positioned so I can see it from my recliner and has an extension probe you can't see that's hanging down below about 2'. I have been trying to stay below 81. Some plants don't get the ventilation they always need and often get to 83. I prefer 75-77 simply because I am more comfortable, that's just not always feasible, it's hot here.


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