To date, horticultural lighting efficiency has been primarily focused on the Photon Efficacy (PE) in micromoles per J from a light source. Research conducted at Purdue University by Dr. Krishna Nemali in partnership with Victor Zaderej has shown that this is not the best measure of lighting efficiency when measured by the ratio of dry matter produced divided by electrical energy consumed (g/KWh). Energy Use Efficiency (EUE) studies have shown that the ratios of Red, Blue, and Green (RGB) light have significant effects on production yields, with different mixes proving optimal for different cultivars. The presentation will detail the results of Purdue research of light recipes relative to lettuce and other plants.