Tent getting hot 84⁰ f HELP!

Buddernugs

Well-Known Member
Yes air temp of 84-85f with leds put leaf temps in the sweet spot but I need to follow vpd chart to see what your rh needs to be at I’ll save you the time it’s 60-65%rh when my flowering tent is 88f my rh% is low 70S never had any mold or bud rot and they fucking explode when your in the butter zone
 

Cvntcrusher

Well-Known Member
Yes air temp of 84-85f with leds put leaf temps in the sweet spot but I need to follow vpd chart to see what your rh needs to be at I’ll save you the time it’s 60-65%rh when my flowering tent is 88f my rh% is low 70S never had any mold or bud rot and they fucking explode when your in the butter zone
Rh? Are you meaning humidity? You have your humidity at 70%?? :O but yeah she's sitting under two CFLs and the LEDs right now. Temp is 84.2⁰F humidity is 41%
 

Cvntcrusher

Well-Known Member
Yes air temp of 84-85f with leds put leaf temps in the sweet spot but I need to follow vpd chart to see what your rh needs to be at I’ll save you the time it’s 60-65%rh when my flowering tent is 88f my rh% is low 70S never had any mold or bud rot and they fucking explode when your in the butter zone
This might explain why even after defo&1 top she didnt even slow down in growth still growing at least a 1/4inch daily.


With nutes, I just put a TINY AMOUNT in 3/4 cup of water and give her that every other day. As well as I mist her leaves once a day as well.
 

Cvntcrusher

Well-Known Member
I moved my inline fan and put it on my plant. And I turned my exhaust fan from hi to lo so maybe with it exhausting less the humidity will go up a little. Now that I have a fan on my plant, I'm going to mist her more often throughout the day to give her some extra humidity.
 

NanoGadget

Well-Known Member
No I was questioning the logic between leaf temperature from air and light and them not being the same.

If you have airflow it should be easy to hang a hundred and so led CFL combo at those temps. Maybe your thermometer isn't in the right place to read accurate.
Leaf temp is leaf temp.. my point was that HPS put out more light in a spectrum that causes excitation of molecules on the leaf surface. I have a laser thermometer for measuring surface temperature. Under my hps I can have up to a 6 degree Fahrenheit difference between air temp and leaf temps at the canopy. With my led boards that difference is typically no more that 1.5 degrees Fahrenheit. Therefore, to keep the actual biomass of the plant at a temperature that seems to provide optimal growth I have to keep the ambient temperature higher.
 

Tetrahedral

Well-Known Member
I have one next to my plant and one directly above my plant at the top of the tent so I can get an accurate temp check. The temp is always consistent with the two. The only difference being the therm by the plant gets a little hotter.

It would be more accurate to say the thermometer getting the most light is the hottest. Certain laws arrange the photon packets into energy conversion along the thermometer independently warming it above the air temperature.

It would also be accurate to say the thermometer with the greatest wind flow over it will have the greatest capacity to loose heat energy.

We could plot a 3d graph of the tent and each coefficient at spacial grid points even determine the flow of energy but none of this is related to the air temperature which is read in a spot away from the above mentioned energies.

Fundamentally growers struggle with this concept, the realization of light as an energy and air as a permeable layer that cannot directly take energy from light is a big step, air has to receive energy from re radiated surfaces. Light travels uninterrupted through air to warm a surface, that surface now looses energy to the air via conduction with the air.

If you put a thermometer in the light it now becomes that re radiating surface and looses it's ability to measure just the energy held by the air.

Look into it, find the right temperature and enjoy some great physics on stuff like the reason the sun burns us but dosent set the earth's atmosphere alight or why it feels cooler indoors than out today with this mini UK heatwave, fuck you Nevada we just got 36celcius, welcome to the real dessert.
 

Tetrahedral

Well-Known Member
Leaf temp is leaf temp.. my point was that HPS put out more light in a spectrum that causes excitation of molecules on the leaf surface. I have a laser thermometer for measuring surface temperature. Under my hps I can have up to a 6 degree Fahrenheit difference between air temp and leaf temps at the canopy. With my led boards that difference is typically no more that 1.5 degrees Fahrenheit. Therefore, to keep the actual biomass of the plant at a temperature that seems to provide optimal growth I have to keep the ambient temperature higher.
I think we need a larger civil debate on this, it's really an led claim not a scientific claim. It conflicts with a lot of things.
 

NanoGadget

Well-Known Member
Perhaps a the folks at Agritech are also not as scientifically literate as you either.

"
High pressure sodium (HPS) lighting, has long been the workhorse in many indoor grow facilities. HPS emits in a broad portion of the electromagnetic spectrum that includes infrared (IR) energy – otherwise known as heat. IR energy from HPS heats the canopy and increases the leaf surface temperature. LED grow lights typically have only a small fraction of their emission in the IR portion of the spectrum, so they do not increase leaf surface temperature like HPS. In fact, it is typical to see a 5°-10° decrease in leaf surface temperature by changing the lighting from HPS to LED. If no other action is taken, the decrease in leaf temperature may throw the VPD out of its sweet spot – thereby decreasing transpiration and photosynthesis. This will most certainly not make you a hero in the grow room.
So how do you ensure you are still in the proper VPD range after installing LED lights? Follow the steps below:
  1. Understand your baseline. Measure the leaf surface temperature and relative humidity while you’re still using HPS. Although humidity is easily measured, measuring leaf surface temperature requires specialized equipment such as a forward-looking infrared camera. Here’s one IR camera that will do the job: tequipment.net/fliri7.html. Don’t assume the leaf surface temperature is the same as the ambient air; this is rarely the case. Once you’ve taken the measurements, the VPD can be determined.
  2. Repeat step #1 after switching to LED.
  3. Determine if your VPD is still in the optimal range. If it isn’t, you should:
    1. Increase the ambient air temperature to raise the leaf temperature to the target temperature that satisfies the VPD requirement.
    2. Modify the relative humidity in the room to bring the VPD into the ideal range. "
 

Tetrahedral

Well-Known Member
I can't follow that, it has very little scientific meaning but it does sell LEDs and make HP's look terrible.

At a hobby level I understand, it's not explaining much though, leaf temp is a much larger dynamic so is spectrum and as pointed out cannabis is not related to vpd in the sense of charts available, it has a faster response curve and would be a different scale and class of plant.
 

NanoGadget

Well-Known Member
You are really just making way too much out of one light producing more IR than another. If you want to bury yourself in a rabithole without actually explaining anything go for it, but I'm not coming along for the ride.
 

Cvntcrusher

Well-Known Member
Can I cut these leaves off since they're being pushed into the dirt by new growth?

Or leave them alone? Cus I don't want my plant to get mad at me cutting off fan leaves. 20200807_193905.jpg20200807_193823.jpg
 

Buddernugs

Well-Known Member
I pull anything laying on or near my coco... never seen an issue... these plants are tuff dude you can pull every leaf off and 1 week later the plant will look like nothing happen...
 

Cvntcrusher

Well-Known Member
I pull anything laying on or near my coco... never seen an issue... these plants are tuff dude you can pull every leaf off and 1 week later the plant will look like nothing happen...
I know! I just worry cus shes only 3 weeks old. I took 3 leaves off. Hetrd how she looks.
 

Tetrahedral

Well-Known Member
You are really just making way too much out of one light producing more IR than another. If you want to bury yourself in a rabithole without actually explaining anything go for it, but I'm not coming along for the ride.
A lot of it isn't absorbed but reflected, let's copy and paste from a scientific study from some great lab technicians who post on researchgate

With solar energy a single layer of leaves will generally absorb 80% of incoming visible radiation, whilst reflecting 10% and transmitting 10%. With infrared approximately 20% is absorbed with 50% being reflected and 30% transmitted.

I'd would be more impressed or inclined to believe you if you talked in actual factual science not the assumption that it is bad and plants haven't spent a few earth cycles learning to deal with it.

Since LEDs seem to miss a lot of things out evidence points to HP's emitting the most photons, since they still seem to match LEDs with most growers and initial claims of 50% more have really died. This now suggests HP's bears close to the same plant usable light but with a lot of added extras.

I think I see that, HP's grows big plants, LEDs don't seem to have the penetrating wavelengths that HP's has. So why add UV the most damaging and least effective wavelength - probably again some rumour that UV adds 20% extra trichs or thc.

And wasn't it LEDs who fell so far down a rabbit hole were only now starting to see a competing product because it was only recent that certain red issues got sorted and another rabbit hole claim on light fixed.

Not here to argue, I really am struggling with the more heat supplements HP's spectrums in led and only seem to find hobbyists making assumptions to sell led lights.

Maybe a more open civil debate so some minor science can be applied to a lot of reading and guesswork.
 
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