My New PC Grow Box Experiment 50watt hps

I converted my old pc case into a grow box i used a 30$ 50 watt hps wall light got a new bulb for it by sylvania then converted it to a remote ballast with a homemade shroud from a lava lamp base and a first aid box for the balast.
the problem - i dont knoww if i should use 2 plant hydro ponic system or two plants in dirt becuase i plan on getting 1 female and doing a scrog ...Help

help anyone?