Supplemental LED light treatments enhanced the growth performance of lettuce

Abstract

As the global population continues to grow, the demand for increased food production becomes more urgent. Vegetable cultivation, however, is limited by specific generation times that restrict yield. This study aimed to assess the impact of supplemental LED light treatments on the growth performance of lettuce. Lettuce plants were cultivated under greenhouse conditions with different light treatments: natural sunlight (control), and supplemental white, blue, and red LED lights, each delivered at an intensity of 100 µmol m⁻² s⁻¹ for 6 hours per day. Seeds were initially sown in black polypropylene seed trays (54 × 28 cm) containing 288 cells (1.9 cm diameter, 3 cm depth), then later transplanted into pots and exposed to the respective treatments. Growth parameters measured included plant height, canopy diameter, and leaf area. The results showed that red LED lighting significantly increased fresh weight, plant height, and canopy size, while blue LED lighting promoted leaf area and canopy expansion. These findings suggest that red LED lighting is a viable strategy to enhance lettuce production, particularly in environments with limited natural sunlight.