MIMedGrower
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@MIMedGrower here is one study. I realize this is not cannabis but I'm sure you will agree that it is in fact very relevant. Picking through in between work stuff if you want a few more just let me know. I would also state that IMO as plant growth is increased VPD plays a larger role. The more light, media providing faster growth (ie aeroponics etc.) co2. The more impact can been seen from VPD. This is first hand observations on my part. I haven't found or looked for any studies to back that up but I feel very strongly about it.
Vapour pressure deficit control in relation to water transport and water productivity in greenhouse tomato production during summer
Although atmospheric vapour pressure deficit (VPD) has been widely recognized as the evaporative driving force for water transport, the potential to reduce plant water consumption and improve water productivity by regulating VPD is highly uncertain. To ...www.ncbi.nlm.nih.gov
Thanks man. I have read this recently. But it confirms what i said. They are using vpd to mitigate 95 farenheight temps or higher with low humidity.
The results are based on that high temp low humidity baseline.
This article does not relate to a controlled indoor grow in my opinion. The standard grow parameters would work as well. Seems the advantage to adjusting using vpd is mostly water conservation for a commercial greenhouse during summer.
For our purposes we can simply adjust watering to compensate for much smaller variations in temp.
Now i see why no advantage to adjusting humidity was found in temperature controlled indoor grows.
The plants get stressed enough for negative impact only at extreme environmental conditions. Which wont happen in my grow unless i have an equipment failure.
With your tightly controlled parameters you shouldnt see a difference with using vpd at all.