temperature question

CannabisMingus

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I am about a year into growing and on my 7th grow in a small cabinet system using LEDs. Now that I am starting to pay attention to VPD, I am taking IR temperature readings off the leaves themselves and - not surprisingly - getting significantly lower leaf temps (76-77F) than air temps (84F).

Am I ok just relying on leaf temperatures to make decisions relative to controlling my growing environment, and disregarding ambient air temperatures?

Shout out to @Mañ'O'Green @Waira @St. Tom

Thanks in advance for your input!
 
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5-7 degrees F temp difference is normal.
The temperature right at the leaf dictates how much vapor evaporates from the leaf.
You are correct using leaf temp.
For temps in the mid 70s F, humidity between 60% and 80% is recommended.
An ultrasonic humidifier placed outside a tent, with fog blowing into the tent, will reduce air temp a couple degrees as the droplets evaporate and soak up their heat of vaporization.

There is an interplay between light intensity, heater setting, humidifier setting, and exhaust fan setting.
I mainly use the humidifier knobs and exhaust fan speed to control humidity, and an inkbird controller to control temp.
 
There is an interplay between light intensity, heater setting, humidifier setting, and exhaust fan setting.
I mainly use the humidifier knobs and exhaust fan speed to control humidity, and an inkbird controller to control temp.

Makes sense. I don't have control over exhaust fan speed, and limited control over temperature outside of the cabinet. I have finally found a humidifier that will work/fit in this cab and have it hooked up to a Inkbird controller. I am now able to keep the grow in line with VPD chart guidelines, and am noticing quite the difference in terms of plant vigor, avoidance of nutrient deficiency symptoms (probably previously caused by repressed transpiration due to low RH) and overall health of the plant. Thanks to AFK community for the education.
 
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I have a humidipro+, been recommended the inkbird controller bit wonder if this would work with the humidipro? Mines are starting to flower so never really hard the fan with carbon filter on before as didn’t need it but aware as they start to flower ill need to run that.. the coupe times I tried with the fan and filter going it’s been a bit of a struggle to keep the fan going and keep temp and humidity at a good steady range

sorry for hijacking your thread man
 

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I have a humidipro+, been recommended the inkbird controller bit wonder if this would work with the humidipro? Mines are starting to flower so never really hard the fan with carbon filter on before as didn’t need it but aware as they start to flower ill need to run that.. the coupe times I tried with the fan and filter going it’s been a bit of a struggle to keep the fan going and keep temp and humidity at a good steady range

sorry for hijacking your thread man
Fan controller to slow the fan down to 1/4..1/3 hooked to the inkbird set for the desired temp range is how mine is setup. I use passive humidity (washcloth and a Tupperware bowl of water) and stay pretty good with it.
 
Fan controller to slow the fan down to 1/4..1/3 hooked to the inkbird set for the desired temp range is how mine is setup. I use passive humidity (washcloth and a Tupperware bowl of water) and stay pretty good with it.
I’d love some pics of everyone’s set ups, hard to picture some. As I’m learning as I go I’m realising there’s a lot better kit out there if I just stretched the budget a bit more and I’d have probably saved in the long run lol
 
I’d love some pics of everyone’s set ups, hard to picture some. As I’m learning as I go I’m realising there’s a lot better kit out there if I just stretched the budget a bit more and I’d have probably saved in the long run lol
Upgrades come with time. My 1st was a 2x4 tent and 2 marshydro ts600s. After friends sampled donations rolled in to upgrade. Main thing, have fun, don't panic, and certainly don't add stress to your life.
 
5-7 degrees F temp difference is normal.
The temperature right at the leaf dictates how much vapor evaporates from the leaf.
You are correct using leaf temp.
For temps in the mid 70s F, humidity between 60% and 80% is recommended.
An ultrasonic humidifier placed outside a tent, with fog blowing into the tent, will reduce air temp a couple degrees as the droplets evaporate and soak up their heat of vaporization.

There is an interplay between light intensity, heater setting, humidifier setting, and exhaust fan setting.
I mainly use the humidifier knobs and exhaust fan speed to control humidity, and an inkbird controller to control temp.
How do you balance VPD in flower? I’ve read to drop RH to 40-50% but my (air) temps are 78-80 (I’ll check IR on leaves, though. Interesting!).
 
How do you balance VPD in flower? I’ve read to drop RH to 40-50% but my (air) temps are 78-80 (I’ll check IR on leaves, though. Interesting!).
. See attached.
 

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