Evaluation between lighting technologies on growing hydroponic lettuce

Abstract

The use of lighting technologies combined with hydroponics has gained increased interest worldwide as a viable and integral horticultural solution to regions with limitations from geography or environmental conditions while offering scalability for rural cities, urban areas, and metropolitans alike. Unrelenting modern uncertainty with climate change, declining water and land supply; urbanization, and not to mention a population soon to exceed well over 8 billion in the coming decades will require innovative interdisciplinary solutions to secure sustainable food systems. In this study, we used a surrogate hydroponic garden to examine the difference in biomass yield from ambient sunlight (control) against supplemental High-Pressure Sodium (HPS) and Light Emitting Diodes (LEDs) lighting. Additionally, we determined the difference in irradiance, illuminance, and luminous intensity between the control and supplemental lighting treatments along with luminous efficacy between the latter. Both experimental groups exhibited higher total biomass of leaves and shoots than the control with measurement of wet and dry weight in grams. The LED group was found to have a significantly higher weight almost twice that of the HPS group. HPS and LEDs had significantly more luminous intensity, illuminance, and irradiance than the control but LEDs significantly outperformed HPS for all parameters including luminous efficacy.