Hi im just starting to get into VPd and im having a hard time understanding how to control it i used an online vpd calculator using my HR, room temp, and leaf temp i got a vpd of (.48kPa) These are seedlings i guess im asking is that a good kPa for seedlings and if not how do i lower or raise it my HR60 and toom temp is 76-80°F
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late reply here. Additional info on VPD for people who want to know:
1. About VPD - https://pulsegrow.com/blogs/learn/vpd 2. VPD Charts for stages of growth - https://pulsegrow.com/blogs/learn/vpd-charts-in-fahrenheit-and-celsius-with-leaf-temperature
Hi, here is a VPD chart I use, it covers seedlings up to flower. However, I only use this for the flower tent and that is where I find it helps the most. I have no control over my temperature but have some over the humidity so I use this chart to get a target for the humidity based on the tents temperature.
I just try and get close to the yellow area in the graph and don't stress about it too much.
And don't forget what Captain Barbossa always says ....
0.4 - 0.8 kPa is perfect range for early veg. I wouldn't worry too hard about VPD during seedling stage but as you're looking at topping for the first time start pulling the charts/graphs out
Try to get the temperature down to 71 if you can unless you can easily achieve 80% humidity, but that's extreme for a plant that isn't uptaking that much water yet.
How honed in is your grow space?