LEDs increase crop yields, blue light, and red light

Research into the application of LED lighting to plant and vegetable production systems has been ongoing, and researchers are trying to figure out how LED lighting affects plant growth and crop yields. Recently, scientists from the Department of Horticulture Science at Chungbuk National University in South Korea published a research report on HortScience, revealing the impact of LED lighting on lettuce cultivation.

The use of LED lighting in an environmentally controlled, closed plant production system allows crop production to be unaffected by external climatic conditions. According to the report authors Ki-Ho Son and Myung-Min Oh, LED lighting has certain advantages over traditional light sources in plant cultivation. They pointed out: "LEDs have the advantages of high light energy conversion rate, low radiant heat output and light weight. In addition, LED lamps can be applied to a variety of narrow bands. Therefore, we can optimize light quality while improving crop yield and quality." Explain that blue LEDs and red LEDs are commonly used for plant growth because chlorophyll a and b are effective in absorbing light in the blue and red bands.

In the study, the scientists used red leaf lettuce and green leaf lettuce and six LED lights for experiments. Scientists studied their growth characteristics including fresh weight and dry weight of shoots and roots, specific gravity of shoots and roots, total leaf area and chlorophyll content. In this study, scientists also measured chlorophyll fluorescence, antioxidant capacity, phenolic concentrations, and flavonoid concentrations, respectively. The report shows: “Using different proportions of blue and red light (blue and red light ratios are 0:100, 13:87, 26:74, 35:65, 47:53, 59:41 respectively). Lettuce, which showed different growth results, showed that red LED was the main reason for increasing the growth rate of lettuce. The ratio of blue and red light in the best experimental group of lettuce growth was 35:65, 47:53, 59:41. ”

This experiment confirmed that blue LED and red LED have positive effects on the accumulation of antioxidant phenolic compounds and lettuce growth in plants, respectively. "Single red LEDs alone can stimulate lettuce plants to increase biomass accumulation, but this single illumination induces abnormal leaf shape and negatively affects polyphenols and antioxidant levels," the scientists said. The plant production system uses a mixture of blue LEDs and red LEDs to enhance the quality and yield of the lettuce crop.