Spectrum - Red LEDs for Green Groceries:
"Of all the colors of the rainbow, red is lettuce's favorite. Chlorophyll, the electrochemical engine of photosynthesis, runs on red photons, which it uses to kick electrons along a chemical pathway that leads to the production of sugar. So if you are growing the vegetable indoors in a factory, why waste energy on colors you don't need? Using a red-LED-based growth process developed by Cosmo Plant Co., in Fukuroi, Japan, instead of a fluorescent-lighting-based one, cuts a factory's electric bill by 60 percent, the company told Agence France Press."
