Lighting question

I'm wondering if someone can help. I ordered a 600 watt hps metal halide light kit. I can only use one bulb at a time, can I buy a reflective wing and socket with a cord then just use the other bulb in that? Or does it need a ballast? Please, any help would be appreciated

Each lamp needs it own ballast unless you have expensive equipment that can run multiple lamps off one ballast separately on 12/12 cycles.

I guess you could do it your way, but I think you would have to unplug the halide and plug in the other bulb every time you wanted to switch.