Grow Room Which VPD chart do you use?

[Animatey]

I was looking at the chart I use compared to another and it seems like they don't always agree on best values or even a good range of values. This was a common theme as I looked through a few of them earlier today.

I also noticed some are based on ambient temps and others based on leaf surface temps.

Which do you use and why?

@Mañ'O'Green curious what you use here

 

[St. Tom]

i have used that screenshot as an example or a guide

 

[Animatey]

i have used that screenshot as an example or a guide
View attachment 1171652

Just4Growers (Everest Fernandez) is the man... I've yet to go wrong following his advice. Thanks for sharing!

 

[St. Tom]

Just4Growers (Everest Fernandez) is the man... I've yet to go wrong following his advice. Thanks for sharing!

no problem growbro and stay safe and carry on growing shit hot weed that's my plan why this virus thing is going on

 

[Garage_Grower]

Here’s the one I use:

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

It let’s you plug in your exact environment values, giving you the plants actual VPD.

 

[Growpito_Aleks]

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

This is what I use. Ambient temperature isn't accurate as it doesn't factor the temperature at the leaves where the stomata are located. That calculator provides an offset between ambient and surface so with the use of an infrared temperature gun you can get a more precise answer

In our current grow, I may run 81f during lights on but at the leaf it's always between 2-3f lower. I am fond of VPD however I believe you get better results in sealed and or heavily automated environments. Combining VPD, DLI, and PAR allows optimal growth to occur and some commercial operations even monitor saturation/EC/pH at the root zone for maximum efficiency and growth whatever those goals may lead to.

I believe it is worth mentioning that photosynthesis is important to all this so even though the upper ranges or lower can be dialed in at some point c02 becomes necessary to drive more photosynthesis. You could grow at 95f but there rest of your environment should match to not waste resources or drive growth you aren't equipped for.

Good luck

 

[Animatey]

Here’s the one I use:

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

It let’s you plug in your exact environment values, giving you the plants actual VPD.

I really like that calculator...

After using that I went looking for an app and I found one I'll probably use that works similar on android called "VPD Calculator".

It takes room and leaf temp, plus humidity and spits out a number. Then it has a list of acceptable ranges for each stage.

 

[GeorgeCloney]

I use this one from https://pulsegrow.com/blogs/learn/vpd
Another member here on the site made the recommendation.
What I like is that it can be set to F or C.
It also has a setting for leaf temp as well.