Well what I'm getting at is that the " light" present at night, is simply not sufficeint for growth, from an intensity stand point; not to mention the exact moment of 'reverting' to veg state will surely be hard to "pin-down" your study seems to require more than a simple life cycle. Here, get an electronic flash, fire it once just at 1 plant, twice at another, three times at the next, all in darkness obvoiusly. any change within 2 days would certainly rule out wavelegth (since the stress would effectively pause growth), modern electronic flashes are between 5500-7000k at upto 50k lumens (whats in my camera box) (more than enough to cause 'stress') next set of plants test with a lantern type light turn it on and leave it for a few more hours each night, that would put the margin of error at upto 3-7days, but you'd figure out how much "ambient" light causes veg. Of course these ideas can be "tailored" to your experiment. :stoned: or just leave it in veg at 18/6 and flower of 12/12 and grow bug fat buds :stoned: