I chose 18/6 mainly because I go to bed at 12 and get up at 6a. The grow is in my bedroom closet with loads of light leakage (until my tent comes in). So mine is a matter of convenience. BUT, then again, transpiration/osmosis occurs during the dark cycle (and other processes as well) so it makes sense to keep them healthy and stress free. Now that's NOT to say 24/0 is a bad thing, just saying that a period of dark IS better for the plant. It might also effect final yield if the plant is stressed going into flowering.
"Plants need light to photosynthesize, but darkness is just as important to give a plant time to convert photosynthesized nutrients into plant growth."
I'm a past photo grower, but I suspect even autos would benefit from at least some dark cycle.
JMHO
Fish
The coolest thing about the auto,
You will get weed whatever light cycle you use!!!!
the best light cycle for an autoflower is......
whatever is best for you!
WORD.