What dimension of grow space are you lighting and what are the plants / crops?

Are you referring to High Pressure Sodium?

Here is a link that might be useful: My Indoor Growing Adventure

haven't measured the space, but it's in the corner of the main room of my apartment.

As for the kind of plants. I was told sunflower sprouts would be fast to grow and good for a beginner, so I was thinking about growing that

400w x 1, you can go with HPS - look under reflectorized lamp (like a Gavita knock off) - which saves money on buying a separate reflector. sunflower sprouts would grow well under a fluorescent bank ( you can get shoplight style fluorescent cheap, you may have to buy new ballast - but you can get high quality used ballast on ebay cheap - which is what I do) I run both fluorescent and HID. for the big plants ( such as more than 18" tall) HID is pretty well needed. - let me know if any more question - paul mozarowski