Hydroponic farming has emerged as a promising solution to global food security challenges, with the market projected to reach $12 billion by 2025. Two commonly used systems are floating raft deep water culture (DWC) and vertical nutrient film technique (NFT) production systems. Despite their popularity, limited research exists comparing water use efficiency and Photosystem II (PSII) performance between these systems. This study begins to address this gap by evaluating the growth of Butterhead lettuce in both DWC and vertical NFT systems within a controlled greenhouse environment. PSII physiological parameters were assessed using a handheld fluorometer (MultispeQ Version 2 – PhotosynQ). Crop-level water use efficiency was also compared between systems. As expected, preliminary results indicated that the DWC system was more efficient in its water use than the vertical NFT system (p < 0.05), after adjusting for baseline water loss prior to plant introduction. More importantly, lettuce grown in the DWC system exhibited a higher mean PSII efficiency (Fv’/Fm’) and greater wet biomass compared to those grown in a vertical system. This study is among the first to directly compare PSII-related traits across hydroponic system designs, providing novel insights into how production method influences plant physiological performance. These findings suggest that DWC systems may offer superior performance, improved water use efficiency, and higher yields, making them a more sustainable and effective alternative for hydroponic lettuce production compared to vertical NFT systems.
