Just wondering if you follow these charts exactly, your thoughts on VPD
I do. I have an AC infinity fan and it comes with an app where i can view my Temp RH and VPD. I try to maintain a 75 temp 55% RH ratio. I think VPD is important and if maintained correctly can increase your yield some.
I have the same fan system, im up in the air on this issue as a whole.
In flower rh should be 40 - 50%, and never 60% or higher. Spikes will come at night when lights turn off. Turn humidifier off just before lights off, and if necessary run a dehumidifier. You also need plenty of air exchange and circulation.Yeah, and prevent it, in your experience
Have you any update on your approach to them? I just started chasing the "sweet spot(s)" and I can't achieve what is said to be "optimal" in most cases. I'm using an AC Infinity fan/controller to get my readings, and I refer to the three charts from PulseGrow that I originally found when I started to think about VPD. First time grow here with plenty of guidance - 4x4 tent, full hydro, 4x4 Spider Farmer light , air conditioner, dehumidifier, heater, humidifier, circ fans - I'm giving them my best, but I don't have a dedicated room for the tent and the temps and humidity levels here often have big swings. Until I have a sealed space for my tent (tents eventually), chasing that optimal VPD will be kind of difficult. Tough too because my grow guides/buddies don't really subscribe to VPD, but control to preferred levels nonetheless.
What were your undesirable results and have you attributed them to anything specific?
That would be a dream. Where I live I keep a dehu running 24/7 just to stay in the 50's%. At lights out I def get spikes and I've caught it as high as 67%. Plus a few times through flower the power company has shut the power of for a few hours bc of pole work there doing. I scan everyday for mold or rot. I'm super paranoid about it. You must live somewhere dry. I've never really had to use a humidifier.In flower rh should be 40 - 50%, and never 60% or higher. Spikes will come at night when lights turn off. Turn humidifier off just before lights off, and if necessary run a dehumidifier. You also need plenty of air exchange and circulation.