Growth Response of Lactuca sativa L. (Lettuce) and Solanum lycopersicum (Tomato) to High pH Levels in a Nutrient Film Technique Hydroponics System

Abstract

This study investigates the impact of high pH levels on the growth of Lactuca sativa L. (lettuce) and Solanum lycopersicum (tomato) in a Nutrient Film Technique (NFT) hydroponics system. Two identical NFT systems were designed, one serving as the control (pH ~7.35) and the other as the experimental group, where pH was reduced to ~6.5 using vinegar, compared to typical hydroponic systems where the pH is about 5. Over 40 days, the biomass of both lettuce and tomato plants and the pH levels of the nutrient solutions were recorded. Results indicate that lettuce in the system with reduced pH exhibited significantly greater biomass and growth rates than the control. The tomato plants also showed faster growth in the experimental system, although the results were less consistent. This study highlights the critical role of pH management in hydroponic systems, suggesting that slight reductions in pH can enhance plant growth, particularly in leafy greens like lettuce. Future research should explore pH optimization for different crops and environmental conditions to improve hydroponic efficiency.