ive done it on accident forgot to pay light bill, out of town for a week came back and $#@!. lights back on like nothing happend 18/6 after a few days saw some pistols slowed growth though but now all my clones are ready to go when i am. ive heard you can cut the first stem though like a clone to keep it living longer and put it domed under 12/12 and it should show sex and not slow the growth of your plant since your impatient by the way that comes from a mj grow book not just hearsay. it will probly save you weeks, since you seem to be planning on cloning you dont want to flower yet any way you want some thing to clone,

im pretty ripped if i left something out ask