Since you have space of 3x4=12 your 400hps is not enough for 50watt/sqft....you need 600watt for that.....if you don't have good ventilation avoid using the 1000MH...it will cause heat problems even on top of the 400hps.....i think you can do your growing even with the 400hps with descent results(33.33watt/sqft).....best of all though is to get a 600watt hps....
newgroweroldsmoker Reviewed by newgroweroldsmoker on . 1000w MH or 400w HPS My grow box is 3' x 4' and I have both a 400w hps and a 1000w MH. I need to know which one would be best to use or should I use the 1000w just for the veg and the 400HPS to bud. or can I just use the 1000w from start to finish? If I get more air flow I may try to use both but that seems like a lot for a box this size. that would put me to almost 120 watts per square foot. :eek: THANKS :D sorry I think I may have posted this in the wrong spot. :( Rating: 5