Humidity

[olbobcat]

It's very simple math. The more plants you have in the space the higher the humidity. VPD is one of the most overlooked problems growers face.

 

[Bob's Auto's]

I use this chart...save it, it might come in handy some time

 

[Death The Cultivator]

I use this chart...save it, it might come in handy some time
View attachment 1415120

Many don't know that to properly measure VPD you need an IR gun to read the leaf surface temperature. The leaf surface temperature creates a + or - offset that helps dial in parameters way better than just using ambient temperature.

Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights

Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...

www.dimluxlighting.com

 

[olbobcat]

Many don't know that to properly measure VPD you need an IR gun to read the leaf surface temperature. The leaf surface temperature creates a + or - offset that helps dial in parameters way better than just using ambient temperature.

Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights

Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...

www.dimluxlighting.com

When I was checking b4 the leaf measured 2 degrees F cooler. No, I don't check it every time. I have a Pulse which is at canopy height off the wall by about 10". You can set the offset to compensate in the App. On the Pulse website you can calculate as well https://pulsegrow.com/blogs/learn/vpd

 

[Hashsloth]

If you're able to grow at 30%, more power to you. Me? Not a chance I'd grow something at that level.

30% RH is about ½ the recommended RH. If you look at a VPD chart, a grower has to go to extra ordinary lengths to come even close to an acceptable value. Photosynthesis isn't the only issue. With humidity at that level, transpiration rates take off and that can cause nutrient issues due to the significantly increased water uptake.

If there's nothing the OP can do about it, well, that makes it easy - he's just got to suck it up. OTOH, why not stack the deck in his favor and create an environment where the plant can thrive rather than just survive?

My tuppence.

Survive??? I think my plants are more than just surviving.

If you're able to grow at 30%, more power to you. Me? Not a chance I'd grow something at that level.

30% RH is about ½ the recommended RH. If you look at a VPD chart, a grower has to go to extra ordinary lengths to come even close to an acceptable value. Photosynthesis isn't the only issue. With humidity at that level, transpiration rates take off and that can cause nutrient issues due to the significantly increased water uptake.

If there's nothing the OP can do about it, well, that makes it easy - he's just got to suck it up. OTOH, why not stack the deck in his favor and create an environment where the plant can thrive rather than just survive?

My tuppence.

Sorry but I find it kind of funny you said all that when you are a new grower. I'll just keep doing what I've been doing and harvesting good smoke from plants grown around 30 percent humidity. And they definitely aren't surviving haha they thrive.

I think I would know what good smoke is and how my plants are doing since I've been growing alot longer than you. Enjoy overcomplicating things when you are just starting out....it helps so much.