I'd say go ahead and set the two up next to each other for this grow, and observe carefully the growth of the plants relative to their positions. Do the plants directly under the metal halide grow more vigorously than those under the hps? How do they compare to the ones right in between? You can have success with either bulb; MH promotes compacter growth, HPS perhaps faster but spindlier growth, so I'd say a combination should be very effective. Whether it's more effective than two MH bulbs is something you have a great opportunity to prove.
vtguitar88 Reviewed by vtguitar88 on . Opinions needed on HPS/MH I have two 400W light systems both are interchangeable for HPS and MH bulbs. My question is during the Veg stage would there be any benefit using one of each bulb or should I just go MH the whole veg cycle and HPS the whole flower cycle? Peace Rating: 5