I think if I read this thread every week for the next year I'd learn something new every time I read it!
What is the maximum allowable RH for late flowering? I've got a RH-controlled ventilation system setup, so it's just a matter of set point. Right now I'm running 55%, which in practice keeps it below 60%, and I'm in
very dry environment (typically 30%) so I'm sure RH is lower near the intake.
Since knna posted the VPD info I've been monitoring my leaf temps, and instead of being 3 C lower, they are 3 C higher at the hottest point! This sends VPD to 1.76. The obvious conclusion: Is my 1000w too close? Would I get faster growth by backing the light off and increasing room temp?
I'm having trouble understanding this statement, knna:
Quote:
| About CO2 at 1200ppm, the RH level to get 0.9-1KPa is over 70%. That is a dangerous level to deal with mold, so a logical conclusion is CO2 enrichment apport little in late flowering stage (2 weeks), because at reasonably RH levels (55%), VPD is outrange, and excess transpiration and probable stomata closure will lead to CO2 unused, without advantages over ambient CO2, or at least over slight CO2 enrichment (500-800ppm)."
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My ambient co2 is never below 1000 ppm, and usually its right around 1200, without co2 supplmentation. I'm not sure why it' so high, but obviously I'm in the "slight co2 enrichment" zone. But considering I'm trying to set up the 'ideal' environment (self-contained cab, air conditioning, heating, bottled co2, lots of light) I need to decide whether I should (a) vent the cabinet and just use the ambient, co2-rich air to control RH, or (b) seal the cabinet and use a dehumidifier and co2 supplementation, which would allow precise control over co2 levels via a C.A.P co2 controller.