azmmjadvocates
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As i understand it, what you say is only actually relevant for Calcium and Boron which are passively taken up by root tips with water, all other nutrients are actively removed from the rhizosphere independent of the rate of water absorption/transpiration.
Also VPD in horticulture refers to Vapour Pressure Deficit specifically, not differential. Essentially both mean the same thing, just ones technically correct and the others not.
Higher EC needs will be necessary as PPFD (up to ~1500ppfd), CO2 levels (up to ~1200ppm) and/or temperature increases (up to ~89F), less so as VPD optimizes(~0.8-1.2 kPa).
This Is a debate id love to see but hate to convolute and sidetrack Squiggleys awesome thread on Chemistry. I don't look at VPD charts, I look at my $350.00 electric bill for a 3000 sq ft home (24 plants me and wife) in Arizona with a pool mind you. As well as me paying much less for nutes because i'm able to run it real real lean, not that I pay much for nutes anyway lol.
I also believe as Fatman stated previously that VPD charts were created for high water content plants like Tomatoes and have little bearing on cannabis. That isn't saying what everyone else is doing doesn't work for then, I just will keep pointing out how versatile this plant is.
Like I said I'd love to hash all this out in another thread, peaceful of course, and I have an open mind. But my electric bill will play a part in my decision.