I've never understood why so many people are into autos, but the best photo period for autos is 18 on and 6 off... I forget where I got that, but I thought it was a reliable source or I wouldn't have used the info. I only grew one auto, along with my others, and it went into 12/12 along with the others so I don't know what it would have yielded if I'd kept it in 18/6, but it yielded very crappy compared to my regular feminized plants so I sure ain't growin' any more of 'em.