Easy if your familiar with LST (low stress training), poke holes in the pot that your growing in and attach plant tie to bends of the nodes and tie down. Your suppose to start it early off but im sure your plant will adjust. Or you can super crop basically the same thing but you bend the stalk of the plant and it will bring itself back up to your light with reduced height.
my super lemon haze plant right now is about 3 ft i just kept the lights real close to them and its not tall at all for a sativa same height as my afghan kush growing side by side