How big of a space? I had 1 400w hps in a space that was 4' by 4' about 7' high I kept my light about 2' above the plants hold your hand between your plants and the light when you can't feel heat on the back of your hand add about 6" or so cause you need room to grow Can't help with ferts I used soil If you can save them great if not I would use some bagseed for a few grows till you have more experiance If you kill some bagseed plants no big loss