I was reading an article today talking about leaf surface temperature and how when running LED’s you need to run a warmer room due to lack of IR from the lights. They suggest around 83-85f room temp to get the proper leaf surface temp. Thoughts? Does your room temperature need to be warmer when running LED’s compared to HID bulbs?
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Yes. LED room temp can be higher than HID because of LST.
Thanks! jmystro with the straight facts…
You can always check the leaf surface temp with one of those inexpensive IR thermometers. It will help get a correct VPD rating in any stage of growth for your plants. Here’s a link to one on Amazon just for reference: https://a.co/d/7u4uP43
Thanks. I’ll be using a IR thermometer to check LST from now on. I’ve never even considered LST before to be honest. One more thing to make a positive impact on my plants.
I’ve always heard that LEDs run about 2-3 degrees cooler (on the leaf surface) than with the HIDs due to the lack of IR. So when you are looking at your VPD then just take 2-3 degrees off of your tent temp and that should be closer to the actual temp of the leaf surface. They probably suggest that range because it’s optimal for overall plant metabolism, but may not be optimal in your setup depending on your situation. Just know the hotter you go the more on point you’ll need to be in the grow to prevent issues. I usually have great results with tent temps in the 78-82 range. Happy growing and #growerslove
Good info from the crew, but LST isn’t always a (-2 or -3) under led’s, depends on hanging height and intensity. And an IR gun like mentioned above will give you a better answer. Been using one since the beginning of growing. Noticed bud sites and leaf surface can vary, with the bud sites being even 2-3 degrees warmer than leaf surface. Just keep that in mind during flower.
I’ll now be keeping an eye on my LST with a IR thermometer. Thanks for the good info.
The amount of water in the root zone can have a large effect on LST compared to ambient temp. This is why the room temp is more guideline than hard rule. I like to run about 79-80 with my LEDs.
If the root zone is dry, LST spikes dramatically compared to the ambient temp. So proper watering practices should be part of this equation.
Interesting! I run soil so I don’t dry out too much. But definitely good to know! Thanks Chad
Good to know as I keep my mom plants in Promix.
YES! I’ve been able to measure this with my IR gun, it correlates with how heavy/wet my media is also. To my knowledge it’s partly due to the stomata closing, cactus and other succulents can be measured with a LST well above ambient air. Love ya knowledge Chad!
Makes sense. If the root zone is dry there isn’t a whole lot of water taken up by the plant, which is probably doing most of the cooling for the plant. As for Captainchronic he runs DWC so one less thing he has to worry about lol
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