2 or 3 mothers, and maybe like 8 - 12 clones at different stages. The space I have right now is about 3 x 2.5 ft for veg, but I have to move the plants around throughout the day so they all get light. It's like 2 or 3 mothers and half a dozen clones right now. It's all real tight in there, but it generally fits. I was thinking either supplement the 2ft 4 bulb T5 I have with the cfls or just replace it with either a 4ft 4 bulb or a 4ft 6 bulb t5... It's really surprising how much coverage this lamp I have puts out, but it really isn't enough, especially since I'm to up the number of clones I have and move to a 600w hps from the 400w..