yep its possible to do it that way or even vice vera - not sure the consequences it seems pretty unclear but from what I gather here are a few things to note:
1) There is a rumor that MH produces more potent buds
2) There is a rumor the HPS produces buds which are more dense
There is a study I read here once showing plants with more of blue spectrum produce more thc because it needs more protection from the sun, the downside is this energy is used in producing thc/resin instead anything else (for example: Bud production) - The "study" goes on to use plants at higher altitudes as an example - these plants get the most "Metal Halide-ish" Light and have more thc but are less dense.
I have came to the conclusion myself that the best setup is to use both so I am using both MH and HPS.
Something everyone seems to agree on for the most part is that HPS is better for flowering and MH is better for veg. (Just keep in mind you can use either/or the entire grow)
My Decision - get the best of both words and use both during each phase in additon to even more supplemental lighting with floro's
Hey, I heard that a blue spectrum is for veg and red is for flower is this correct? Also is the blue spectrum a MH while a HPS is a red spectrum? If both are correct would it be possible to grow from seedling to harvest with just a red spectrum HPS bulb or would my plants suffer?