Temps for Growing with LED

I’m new to growing, but am very excited. I’ve been doing a lot of research and decided to use LED but am finding some conflicting info on temps...
“When a leaf absorbs IR, it heats the leaf creating actual leaf temperatures of 5-7 degrees higher than the 78F degree air temperature. Thus with light sources rich in IR, an air temp of 78F is functionally 83F-85F to the plants metabolism. LED’s emit no IR, so to achieve similar metabolic rates found in HID or greenhouse conditions at 78F air temp,LED growers need to run the room air temp at 83F-85F. Air temp can also be lowered by 3F-5F in the last 2 weeks of flower to enhance ripening, but remember as relative humidity goes up the air temps go down, so be prepared to make adjustments accordingly.”

so reading this, would it be accurate to adjust my temp on 5 in seedlings with 2 sets of leaves to 83 deg f?

thanks in advance

I would be surprised to learn that an LED panel had enough IR lights to throw off your original numbers.

I understood it to be the opposite.”LED’s emit no IR, so to achieve similar metabolic rates found in HID or greenhouse conditions at 78F air temp,LED growers need to run the room air temp at 83F-85F.”

That may be the case. I know there are boards that do have IR lights incorporated into them.

Be careful going any hotter then that. You will not hurt it a bit lower but much hotter and things can go south quickly. Remember Sativas and indicas will respond differently to temp. There is no 1 set rule.

All I know is when I see my grow tent go above 80, I start to sweat no matter where I am.

Jcann said:

I understood it to be the opposite.”LED’s emit no IR, so to achieve similar metabolic rates found in HID or greenhouse conditions at 78F air temp,LED growers need to run the room air temp at 83F-85F.”

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There is no set 'perfect' temperature for growing. You are correct that when growing with LED the room temps should be higher because of the lack of IR, but if your plants are happy I personally wouldn't adjust.
Glad to see BudgetMessiah has made his way over to RIU.

Thanks everyone

I run my led room at 84.5f....60-70% rh...No co2.....Last few weeks of flower ill begin lowering temps and rh to avoid bud rot or mildew etc...

Any higher temps and id want CO2 for sure. You can get away with lower than 84.5 but i wouldnt drop below 80f under leds without ir

Im running straight VPD ofcourse, so with that comes insane air movement, my room feels like a sticky , humid hurricane lol

I’m at 82.4f, 55-58 RH%. My room also feels quite sticky, glad I upgraded to oscillating fans

diggs99 said:

I run my led room at 84.5f....60-70% rh...No co2.....Last few weeks of flower ill begin lowering temps and rh to avoid bud rot or mildew etc...

Any higher temps and id want CO2 for sure. You can get away with lower than 84.5 but i wouldnt drop below 80f under leds without ir

Im running straight VPD ofcourse, so with that comes insane air movement, my room feels like a sticky , humid hurricane lol

Click to expand...

Sorry, what’s VPD?

Jcann said:

Sorry, what’s VPD?

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Vapor pressure deficit


Google it and you will see many VPD charts that show optimal ranges for temps and rh at various stages of a plants life.

This is the one I use.

This is great! Thanks everyone!