how benifcial is it to have a hps compared to mh during flowering???

I currently have 3 metal halide 400 watt lights. only using one at the moment, but I know its beneficial to have a hps for flowering. does it make that much of a difference? are the buds gonna be double the size or are they going to be noticeably harder? thx a lot

In order to really see what kind of a difference you would obtain by using MH versus HPS in bloom, you would really have to have clones in split rooms receiving the same treatment, except that one group would be under a halide lamp and the other group under sodium. You certainly should see a difference, but nobody could tell you exactly what the hypothetical yield/potency differences might be.

HPS has more orange-red light, which is known to be conducive to flowering. During autumn there is more light in the orange-red spectrum.

You tend to see less stretch and more compact/leafy growth with halides, that have more light in the blue spectrum. I've been using both MH and HPS for bloom.

Nullis has it down pat! Use a study of what the sun does outside and "try" and replicate it. I run 2 4x4x7 tents inside. Last year, I had the two tents going with the same bean strains. When I switched to flowering, I only changed one of the tents to hps and ran 3 weeks into flowering. After 3 weeks, the veg (mh) tent had very tall spindly nodes, while the hps tent was much shorter and bushy throughout. I then changed the mh tent to hps. My final yield was about 1/2 of the other tent that went straight into hps at flower time. BTW, when I ran mh and hps into flower on the tents, they received the same nutes, as well. Rock on...