Milson, you've been saying that for 2 weeks. LOL These lights just don't allow much stretch, I've accepted that. I want them at 1 foot, then I'll start flowering them. After the Orange Gasm grow, I know I can produce massive weight with short plants. Actually, I'm not disappointed as it makes the grow SO MUCH EASIER in the long run.
No CO2, why bother with it. What am I going to do, increase weight another 10-15%- that another 10-15 oz? I told everyone that final weight would be the deciding factor and it was decided for me. 106 oz from the last grow is plenty for a single grow. I still have the Exhale bags hanging in there, which are supposed to last around 6 months. But with the exhaust running while the lights are on, I don't see how it's worth it (very much, anyway). The CO2 increases the growth rate so much, it would just be more to handle. I've also heard from 2 LED companies that are interested in me doing a documented grow with their lights, so I'm in early discussion with both of them (which means a second room!) if I move forward with one of them.
Regarding VPD, In cannabis cultivation, VPD refers to the difference between vapor pressure within a plant and the vapor pressure of the air surrounding the plant. VPD is responsible for driving a process in the plant known as transpiration, which directly impacts plant health.
To be honest, I'm more of a meat and potatoes guy- as opposed to others on here, I don't dwell on the details, just the results. I was a Biology major in college- lots of plant knowledge (although I ended up with an accounting degree and then an MBA in Finance), ran the 2nd largest organic farm (875 acres) in the U.S. and was a Director of Operations for a large Garden Store chain in my area. My background allows fine results with basic knowledge, but lets not forget all the growing too since 1988 (12 + 20= 32 years- Oh my god, I'm old). LOL