theres no way to say exactly how much u can yeild, it depends on the lights, and the care they recieve. If u keep um as healthy as they are now u can get alot of nice bud, i did see some cfl's,any other lighting????cause that will make a diffrence. i use a 4oow hps, and i can get close to a Qp (from 4-5 plants) given they stay healthy r nothing majorly bad comes up. give a lil more info on ur setup and we can prob give u a better insight on wht to expect.. Nutes used,soil,Lighting,fans,ect. keep it green