Research Brief: Boosting Yield in Hydroponic Lettuce and Arugula
June 16, 2025 
Researchers at the University of Georgia (UGA) explored how optimized nutrient management and adaptive lighting control affect hydroponic lettuce and arugula production in two recent studies. The first study focused on the use of potassium and lighting on lettuce, and the second evaluated how different soilless CEA systems affect the yield of lettuce and arugula.
In the first study, researchers grew hydroponic lettuce in a greenhouse and tested nutrient solutions with varying potassium concentrations under different daily light integrals (DLIs). They tested three potassium amounts (200, 400, and 600 milligrams per liter) at six different DLIs (11.1, 12.9, 14.6, 15.9, 16.9, and 17 mols of photons per square meter per day). Each DLI was achieved by integrating an adaptive lighting control system over a 16-hour photoperiod (the amount of light plants receive in a day). The researchers found that increasing potassium levels didn’t improve their lettuce yield, but having a higher DLI did.
For the second study, researchers grew lettuce and arugula in a greenhouse using four different CEA systems: deep water culture (DWC), nutrient film technique (NFT), vertical towers, and aeroponics. They analyzed how much water, space, and energy the systems used, and how well the plants grew in each one in the span of 28 days. Their results indicate that arugula grows most successfully in aeroponics systems, and that lettuce is better suited for DWC and NFT systems.
Together, these studies give growers actionable insights to improve their lettuce and arugula yield by using adaptive lighting and matching the right hydroponic system to their crops.
The full research findings can be found on the ASHS HortScience electronic journal website at https://doi.org/10.21273/HORTSCI17806-24 and https://doi.org/10.21273/HORTSCI18391-24.
