Hopefully ur talkin 12-15 not including the pot, But it can be done. If ur usin cfl's they work wonderfully for small plants cuz u can keep em close without burnin. I'd say top the bitch as soon as it's big enough and keep the light close as possible. Come flowering time, be ready for the plant to double in size so u'll probobly want to start flowering when its 6-7 inches tall, then if it's gettin too big, lst it.