Something ive been wanting to bring up and discuss as a side topic in its own thread instead of jumbling it into the “Cheap LED Strips : A Viable Alternative” thread to avoid congestion.
So to the point when running LED lights we should be running higher temperatures than one might figure.
Reason being is the Leaf Surface Temperature of our plants is lower under LED lights than what it would be under say HPS even if the room temperature is exactly the same, reason for this is HPS throws out quite a bit of IR heat where as LED’s do not and with that you could easily see a 5C+/13F+ difference at the leaves.
This difference can make a considerable impact on the rate at which our plants transpire and there ability to cool themselves when exposed to high amount of light, and if one doesn’t know or consider this fact they will most likely experience slower growth than what they may be use to, so consider that and if you can grab leaf temps of your plants with an IR thermometer before you switch or consider bumping up your room temperatures past “older” recommended room temps to allow for greater growth.
Personally at the time of this posting i have my exhaust fan setpoints in the 31-32C region “88-90F” which for myself corresponds to leaf temperatures in the 28-30c range “82-86f” which works for me, different cultivars and or grow environments may warrant different setpoints though.
Obviously do your own experimentation for what works for you and totally feel free to share that information here so we can get a discussion going about it and working out some more ideal temps for LED growers.
Also to add some outside OG info, here is a great page by Blackdogled about Leaf Surface Temperatures with FLIR measurements under LED’s, MH and HPS to illustrate the points above.
And a pic grabbed from their site, so full credit to them and there work, i just added this as a pic for the oogles and not to get into discussion or nerd feast on comparable accuracy of light wattage vs observed photon density and the likes at sites measured and how close the comparisons are.