Quote Originally Posted by demoreal
Has anyone done a side by side with an MH and HPS for flower? Does the MH create more leafy growth?
MH does promote more leafy growth, hence it's used for veg, and the red of an HPS mimics the fall (harvest) sun.

i have read a study, and although it doesn't relate to MH vs. HPS specifically, it is still interesting. two crops of MJ were grown, one at 4500ft elevation, the other at 9000ft. the crop at 4500ft had about 25% more yield, but the one at 9000ft had better trich production. i know this pertains more to UV than spectrum (although, UV is a spectrum, or a group of really). with that being said, blue light and light closer to the blue end of the spectrum is more powerful than light at the red end due to frequency (i believe).

good growing!


-shake
headshake Reviewed by headshake on . Drowning in conflicting plant graphs - help! (LED) Still trying to design my LED light through clear understanding and not just mimicking. There is one photosynthetic response curve that shows yellow light has more effect than blue light and that green, while lower, is almost as useful. Other articles say green light may stunt plant growth and that yellow is not much more useful (despite the huge success of HPS). Then there is the photosynthesis action spectrum showing that violet/purple light (400nm) has the highest absorption peak Rating: 5