im not really sure.. but im also interested in this question as well as i will be purchasing a 250 hps... the one i was looking at had a 28,500 lumen output... and with 3000 lumens per square foot being a good target.. i'd have to say that as many plants as you can fit in like a 2 1/2x 2 1/2 foot square is as many as you can grow...and it also varies greatly on how much reflectivity you have on the walls..... but thats just a guess
good luck
~Notorious
notorious P.O.T Reviewed by notorious P.O.T on . How Mant Beautys Under A 250w MH/HPS? I Have a 250W System with both a MH and HPS Bulb. space is not a issue but i'd prefer to do it in the closet. How many 3-4 Ft Plants (Pure Sative) can i fit under a 250w system. I've read on many dif ways to harvest every two weeks, so i want to try and aim for 2-4 OZ. Is that even possible with a 250w system and 3-4 foot plants?. Also what size contaner will be good for the entire life of a 3-4 foot sative plant with out root bound occuring. Rating: 5