Advancing sustainable production in hydroponic systems through the integration of compost-based liquid extracts as a sustainable nutrient source

Sustainable food production and organic waste management have become critical global challenges in recent years. In response, this study explored the potential of using compost-based liquid extracts to replace synthetic fertilizers in hydroponic production. Worm casting tea (WCT), in-vessel compost tea (InVCT), and R&M manure compost tea (RMCT) were analyzed for their chemical compositions and effectiveness in supporting lettuce (Lactuca sativa) growth in Deep-Water Culturing (DWC) hydroponics. Nutrient solution dynamics and resource inputs were evaluated at tea-to-water dilution ratios of 1:4, 2:3, and 3:2 (v/v) and compared with a synthetic nutrient control. The results showed that WCT (2:3), RMCT (1:4), and InVCT (1:4) produced the highest biomass yields for their respective treatments and WCT (2:3) also required the lowest water and electricity inputs per kilogram of shoot produced. The lower performance of RMCT and InVCT was attributed to elevated ammonium concentrations, high total dissolved solids, and limited nitrate availability. Although WCT yields were ∼20 % lower than those from synthetic fertilizers and required 20–36 % higher resources, the nitrate use efficiency and tissue nutrient profiles were comparable. These findings suggested that WCT had strong potential as a stand-alone organic nutrient for hydroponic systems. RMCT and InVCT, while less effective than WCT, still outperformed many previous reported compost teas or vermicompost teas, suggesting their potential as organic nutrient supplements.