One of my first gardens was a 400 watt HPS, but one of the plants got really tall. I added a 125CFL self ballasted grow light, and it was difinetly worth the cash. All you need is a special cord that is available at your grow store to accomodate the large base of the self ballasted CFL, about $20 or less and the light is less than $35 if you shop around. Good luck, I hung mine vertical because i had to, but it worked great.