The other LST, or why plants under LEDs favor higher temps for best growth

[Onamatopeia]

From a couple of fascinating articles:

The gist is this: LEDs, which alone are "tuned" to only give the plant usable light, have a very interesting side effect. No wasted light means, on the surface of the leaf itself, less heating. This means that, in a room at 75 degrees Fahrenheit, the plant's area of metabolic action under LED lighting will be on average 9 degrees cooler than any other kind of lighting.

The implication being that your LED grow room should be warmer than your grow room with any other lighting.

So, in addition to the lights giving off less heat, and less electricity required to to cool the grow to a normal operating temperature, you also may factor in that the LED lit plant should grow better at 80 than at 70, and may be fine well above 90.

(And the other LST I am referring to is "Leaf Surface Temperature")

I submit this to you grow masters for your views!

 

[Onamatopeia]

The research only documents the leaf surface temperatures with different lights with a room at the same temperature.

So, on one level the reduced LST of LED-light plants could mean you can run your grow 9 degrees warmer, if LST were the only consideration. But the ambient heat will affect the plant in other ways too. For one thing I know you are not supposed to let the soil temps get too hot. Maybe pests and disease are worse, too?

I am curious if anyone knows whether running your grow room at these warmer temps invites other problems into the grow, assuming that the leaves like the temps?

 

[Happy Hemper]

Very interesting thoughts but I haven't a clue as to the answers. I wish that I had the resources to investigate this. I used to grow outdoors in the subtropic part of FL. where the temp. and humidity regularly was in the 90's during the day until late in the growing season. Our plants were harvested in November.
I do hope that some of our fine members will have the desire to further explore these subjects.

 

[Ruthy]

My first thought was to put a buffer at the base of the plant to keep the soil cooler and let the temps rise to the 80deg mark if this is the case.
I am a tinker at heart and down the road I would love to try this, also thinking of making some kind of base that will spin the plant 360deg during the light cycle to help with better coverage.

 

[JBUptown]

My first thought was to put a buffer at the base of the plant to keep the soil cooler and let the temps rise to the 80deg mark if this is the case.
I am a tinker at heart and down the road I would love to try this, also thinking of making some kind of base that will spin the plant 360deg during the light cycle to help with better coverage.

Ruthy,
A battery powered Lazy Susan ... IKEA sells them.

 

[Ruthy]

Ruthy,
A battery powered Lazy Susan ... IKEA sells them.

I think it would turn to fast, I am thinking that it only does one rotation per light cycle.
Good idea if you could adjust the speed.

 

[Onamatopeia]

Anyone curious can Google leaf surface temperature and cannabis. When I post the links, they get taken down but I don't know why.

My personal experience does line up with the study I read. My plants at 75 don't seem to grow as fast as when they are at 85, and 90 does not seem to faze them at all.

 

[Resinjunkie]

I grow in sub tropical climate in a cabinet inside a shed with no ac but lots of fans that is the key to controlling the humidity and temp which my cabinet gets pretty hot and my girls seem to like. Usually we can grow here from Sept to April at the latest but this year I got a late start and have a few more weeks. It's no easy task at this time of year in fla

 

[BeccaBuds]

I bought an Extech IR200 Non-Contact thermometer because of the pandemic and was delighted to discover it also has a surface temp mode. I've been using it to monitor the driver temperature of my new LED lamp and started measuring the temperature of the growing tips. This infra-red thermometer is turning out to be a very useful new tool for monitoring plant health via LST.