Yes you can flower withMH as long as the plant is on a flowering schedule.... although the plant will still flower, it will not produce the yield an HPS would, there are different colors in each lights that effect plant growth differently through stages in their life. hope this helpssomeone told me you can flower with mh... dont know if they know what their talking about or not... soo wondering if its possible..and if so... what kind of buds will it produce. thanks