Heck ya put that in the window ledge for as long as you want and when ready put back in the tent at 12/12, your golden. Had to do this with 6 clones I cut from a plant 4 weeks into flower. The plants are mutants and have bud sites everywhere. The other posters saying you have to do 18 hours are confusing things. You can veg a plant for 24 or 20 or 18 or 16, but all you want to do is keep it alive until your tent is free, so any little bit of light ( given for many hours) will keep it growing. Once sun goes down move it under a small house light or keep in a bright room even. Don’t sweat it.