I think they have you set. The charts themselves are cheat sheets to keep from having to do the math. But there is a number for vpd, it will be like .75 to 1.75 or somewhere there abouts. Also, there are different ideal vpd to run depending on stages as pointed out too.
To go extra nerd for you, there is also different vpd calculations based on what you use for lights. Based solely on corrections for differences in leaf surface temperature under different types of lighting. I would just use proper chart that applies to you though. Then line up where youāre at in grow and target middle of the line for that.
Hereās an amateur tip free of chargeā¦ pay extra special attention for abrupt changes in nutrient uptake when making noticeable changes to vpd. Sometimes when your vpd is way off plants will appear extra hungry. If youāve been adjusting nutes by reading plants then make a correction of vpd, you can overfeed pretty quickly. Or suddenly running into vpd issue can make your plants look really hungry.
Sorry, I donāt mean to hijack this post but I have to say it :
From all the reading Iāve done on this forum, I think that @dbrn32 should really be called Appollo.
Apollo is a god of light and could be thought of as the god of Enlightenment!
I am seriously impressed with your knowledge and your willigness to help everybody. And the others shouldnāt feel left out, everybody I interacted with in this community has been great and helpful. This really brings me back to the sixtyās spirit of Peace and Love! You people warm this old hippieās heart!
Thanks
