I monitor CO2, but don’t supplement. I am in the grow room a lot, so it stays around 800 most of the time, but not consistent enough to be counted on to help. I tried it with the sativas to see what they would do, thinking they were tropical and might like the heat and extra light, and got my answer. They shot up like rockets. I also believe that when they are flipped makes a difference, if from seed and less than 70-90 days from germination, they are not yet ready and will tend to shoot up until fully mature, so vegging longer or taking clones then flowering them has an advantage, they will stretch lees and flower quicker. I am referring only to true landrace type sativas, perhaps heavy leaning hybrids. I was told this by several older growers and have read it as well, so thought I’d test it a bit. Here’s my Golden Tiger from last grow at 7 weeks, she was about 1.5 feet tall when flipped, here she’s pushing 6.5 feet already, and I ended up putting another trellis screen up and pulling her down drastically throughout the grow.
<(Image removed)>
Here’s s clone taken from the above plant at about 4 weeks into flower and revegged, then put into flower just over 7 weeks ago, although she was much shorter when flipped for obvious reasons. With all else the same, or very close, the stretch is dramatically slower, and the buds have developed faster as well. I can’t positively conclude which made the biggest difference, but heat, light and maturity certainly play rolls in sativa stretch.
<(Image removed)>
