The effect of different LED light on growth and anthocyanin of hydroponic red oak lettuce in a closed system

Light emitting diodes can potentially be a useful tool for indoor lettuce production. The aim of study is to test coloration, biomass and anthocyanin concentration in red oak lettuce grown under different LED lighting. This study will provide us with insights on how the LED light spectra can improve coloration and increase productivity. The experiment was conducted in a closed system, with light parameters, temperature, and humidity controls. Twelve lighting treatments were used: 1) green LEDs; 2) red:white LEDs (3:1 ratio); 3) red:blue LEDs (5:1 ratio); 4) red LEDs; 5) red:white LEDs (2:1 ratio); 6) red:white:blue LEDs (3:1:1 ratio); 7) blue LEDs; 8) red:white LEDs (1:1 ratio); 9) red:white:blue LEDs (1:1:1 ratio); 10) white LEDs; 11) red:white T8 type (1:1 ratio); and 12) red:blue LEDs (3:1 ratio). Significant differences were found between treatments for color ratings, growth, biomass, and anthocyanin concentration. Results showed the blue LEDs treatment provided a higher red pigment in the plants than any of the other artificial light treatments. The red LEDs treatment increased plant growth, biomass, photosynthesis efficiency and phenolic compound. The use of supplementary LEDs lighting technology could provide an alternative lighting source to improve the red oak lettuce growth in closed production systems.