how to keep my sativa short?

ive got 5 plants 4 blue cheese and 1 jamaican lambsbread the lambsbread is taller than the blue cheese but i wanna change to 12/12 soon and i dont want the lambsbread to outgrow its closet what can i do to make sure that the lambsbread stays roughly the same height as the rest help pls

tie it down.. search the forums on LST ing. it is low stress training and you basically just bend and tie down the monster plant in turn letting more light reach the lower bud sites.. sativas are tough indoors due to height.