Influence of LED-Spectra on Yield and Phytochemical Content of Chinese Kale (Brassica oleracea var. alboglabra) in a Hydroponic Vertical Farming System

Rapid urbanization and population growth demand sustainable food systems. This study investigated hydroponic vertical farming with LED lighting for Chinese kale (Brassica oleracea var. alboglabra), comparing white LEDs (WL), 20% red + 80% blue (20% RL: 80% BL), and 80% red + 20% blue (80% RL:20% BL). Plants grown under control conditions were assessed at weeks 2, 4, and 6. The 80% RL:20% BL treatment enhanced fresh weight, leaf area, root length, and biomass, while 20% RL:80% BL maximized chlorophyll, anthocyanin, and phenolics. Leaf number and quantum yield remained similar, though stress was evident. The findings of this research highlight red-dominant light for growth and blue-dominant light for phytochemical enrichment.