Ok, I’ve had this chart pinned to my grow room wall forever.
I’ve generally followed it, and just looked at my temp / RH, cross referenced and knew where I was.
OR SO I THOUGHT
On the same page that chart can be found:
Vapor Pressure Deficit - The Ultimate Guide - Dimlux Lighting - The Best Grow Lights
You ALSO get a nice little calculator where you can punch in your own numbers.
Well, I wanted to integrate a VPD reading in my home assistant controller, and found someone had already put together the code for it using my sensors. But GAH! it didn’t match the chart!
Current temp 77.63°F / RH 49.3%
CHART VPD 1.09 kPa
Calculated VPD via code 1.64 kPa
Calculated VPD via the application on the page 1.64 kPa
I now feel like I’ve been following the wrong / an incorrect VPD for a LONG time. Mind you the code writer showed his calculations, and it makes sense that the calculated values are correct, and the chart is actually incorrect.
Thoughts?