LED growers, are we hotter than everyone else?

[Beach_Town_Brit]

Hi all

Grateful75's thread got me looking at the BlackDog LED site and I found this interesting article (not the lst we're used to):

https://www.blackdogled.com/lst

The article suggests that compared to MH & HPS, plants under custom spectrum LEDs can handle higher temps and that their optimal temp may be 85 not 75. This doesn't apply to full spectrum LEDs.

What do you all think? Has this been your experience?

Certainly, my grows tend to spend more time in the 80s than the 70s...

[ZigZag]

I've heard that you can grow at higher temps with LED's than with other types of lighting. All I know for sure is that they seem to produce as much heat as HPS, LEC or HID....Since high power LED's are too bright to get too close to the copy (recommended heights for flowering are usually between 18-28" depending on manufactures recommendations)....maybe the room temp can be a little higher because the source of the heat is further away than if you were using HID/LEC/HPS. The heat from an LED light will dissipate more evenly before it reaches the canopy. Maybe. For this current grow I'm using Fluence LED lights_the VYPRx model (2 lights_great for veg and flowering but a bit much for seedlings, even at 48-50"). Two of them about 12" apart put out a very even
PPFD over our entire grow space_6x 3.5'. Perfectly even coverage of 900 PPFD over the 3.5' area with just a little falloff on the very outside of the 6' space (the lights are 4" wide by 4' long. Fall off on the ends is about 100 PPFD. These lights are super bright compared to what I've used before and draw less watts. They are convection cooled. Each light has a ballast that does get warm, but you can mount it up to 6' from the lights to keep heat away from the plants. It does produce heat though, as much as you'd get from any light(s) in the 700 watt range. It's just not placed over the plants... and the lights themselves don't require any fans to cool them. I use a small fan blowing across the lights but not down on the plants and that does a good job of keeping things cool.
If your temps are often in the 80's then just make sure to have good ventilation and give em plenty of water. I tried using CO2 once but it didn't seem to do anything for me_but people say its good for temps over 80. Cheers!

[ZigZag]

PS: It would seem the wattage of each LED (2, 3, 5 watts, whatever) would determine how close you could place them to your plants and how much heat they would direct down towards the canopy.
Maybe certain colored LED's put out more heat than other colors....so maybe the spectrum produced by a specific light produces more or less heat ......than say one with a slightly different spectrum with the same overall wattage. Might have to check into this some more.

[Beach_Town_Brit]

Hi Zig Zag, that's a good point and I'm sure that distance from canopy and heat spread is a factor too.

Personally, I find the 5W chips in my Roleandro underwhelming. Even at 16" from the canopy they're not all that.

The article on the BlackDog site suggests that because their LEDs don't put out a lot of photons in the middle of the spectrum (much like most pink/purple grow LEDs), less harmful photons are bombarding the leaves allowing them to function more efficiently and thereby thrive at higher temps. Indeed, they go so far as to suggest the ideal temperature is in the 90s, not just that the plants can handle higher temps.

[Skeet]

I'm currently running my room at 82 to 84 degrees. Without getting to technical LED grow rooms need higher temps to process something that happens while growing.(forgot the technical name) HPS lights carry that heat with the spectrum to the plants but LEDs do not. Also if you use CO2 then it requires even higher temps. Hence why I run my room at those temps. Keep in mind you have to now pay more attention to humidity.

[Vapo69]

Hello all, as some of you might know, I've recently grown a monster auto that is too tall for my tent/lights, even after supercropping the top is still much too close to the LED's, I expected all the leaves to frazzle but this is not the case, it seems only certain colours have burnt the leaves in small patches, I have no idea which cause I try and rotate as much as poss.

[ZigZag]

Keep that rotation going_ bad light burn will lower the THC in your final harvest. LEDs can do that without much warning. Keep an eye out for any bananas or other male parts in case your plant decides to go hermie. If the pistils on the sugar leaves start turning white, then you really need to do something. If you start to run out of space maybe you could put a sheet of something like frosted glass, plastic, even some of that paper stuff my wife uses in the oven_ doesn't burn but lets some light through...worth a try anyway. If you really get in a bind and the "roof of your grow space has a reflective ceiling maybe you could mount your lights upside down, bounce the light of the ceiling and back down to the plants. This will cut the intensity and spread out the light more evenly. Just some idea's_ never have that problem cuz I can mount my lights up to 70". Good luck, hope you find something that works!