Good Morning DGC,
Let me start off by saying thank you and to your crew! You guys are doing such a great service to this industry and this is an amazing DGC community. I am a pretty new subscriber (less than 2 months) found you guys on youtube and I also listen to DGC on podcasts. Later today I’ll drop for a year sub! The info I have received from listening to your program is far more valuable than the tuition!
The question I have is should we as growers really try to chase VPD? No matter what I do it appears to me (using pulse) that the VPD is all over the board. I have a 3x3x6 Vivosun tent, Vivosun 6″ intake and exhaust fans, oscillating fan, 1.2 gal humidifier, pulse monitor, HLG 550 rspec, Exhale CO2 bag, and fabric pots on a pot elevator. I live in SoCal (Huntington Beach) and the weather here is pretty damn good for growing cannabis.
Currently I am growing a GG#4 feminized autoflower (week 4 in veg) from growers choice seeds. The grow has been great, using GH nutes the flora trio, mammoth P, cal-mag, coco loco, PH’d at 5.8, TDS is 700 ppm. However the problem I am having is the VPD is to touchy (scaling) when trying to target the “golden” temp and rh. I have heard many times from your show that “ideally” temps in the range of 80f-85f with RH in the range of 40%-50% is golden. No matter what I do that just isn’t happening, if I slow the exhaust fan down temps rise and rh falls, because we all know rh is the inverse of temp. If I speed up the exhaust, temps fall and rh rises all the while vpd is going from 1.0 to as high as 2.4. According to what I have read, ideal vpd in veg is 1.0 and in flower 1.2 – 1.5, the problem is how the hell can I get there at the ideal temp and rh? Anything hotter or colder the vpd is way to high or to low. As a new grower I’m probably to fixated on it just like a new brewer is to their first brew session. Anyways keep up the awesome job!