Lighting Strategies to Enhance Crop Quality in Controlled Environment Agriculture

Fresh vegetables and fruits are essential for a healthy diet, yet their quality can decline quickly after harvest. This thesis investigated how adjusting preharvest growing conditions in high-tech greenhouses and vertical farms can improve crop quality at harvest and during storage. The research focused on End-of-Production (EoP) lighting, where short-term changes in light intensity, photoperiod, and daily light integral (DLI) are applied shortly before harvest. In lettuce, increasing DLI in EoP rapidly enhanced nutritional traits, preserved sensory quality during storage, and extended shelf life, demonstrating how improved at-harvest quality can strengthen postharvest resilience. In dwarf tomato, combining high light with elevated electrical conductivity (EC) in the root-zone enhanced fruit nutritional value and flavor compared with high EC alone, while also reducing the yield loss typically associated with high EC. Together, the findings strengthen the scientific basis for designing integrated strategies to improve multiple quality attributes in controlled-environment agriculture and ultimately support the supply of healthier, more enjoyable produce to consumers.