Thanks for that Antics, I'm not sure they'll suit my grow if they stay on 18/6. I think I'' stick to photo's
Technically, you can grow autos with any light schedule, and they'll flower. People keep them on 18/6, and some on 24 hours, because they believe that the plant benefits from being able to take 18/6 and continue to flower without reverting back to veg. You can easily grow Autos and switch to a 12/12 for them, I just don't know if it'll reduce yield or not.