Also, green light is great for plants. Don't let old science fool you. Why do you think an HPS lamp works so well despite about 80% of its visible light output being green and yellow?
When I GIS "photosynthesis spectrum", I see a million different curves, but they all peak in red and violet-through-blue-green. Even if you don't look at emission and absorption curves, just look at a plant. Its leaves are green. That means that it's reflecting more green light relative to other colors. That should be a clue that green light isn't the most efficient choice for feeding plants. (It's not conclusive, of course; nature's paths aren't always optimized for efficiency.)
Why do HPS lamps work so well? I don't know, but here are some possibilities:
They're many times more efficient than incandescent grow lamps, so you get more usable light per watt even if its spectrum isn't ideal.
HPS grow lamps are tweaked to produce more red light.
HPS lamps put out a huge total radiant flux, so they're just brighter than alternatives, in both useful and wasteful wavelengths.
Can you provide some supporting evidence that "green light is great for plants", when it's near the bottom of the photosynthetic absorption spectrum?