Comparative assessment of commercially produced cow manure, frass, and cucumber leaf digestates as fertilizers for hydroponically grown basil

The increasing demand for sustainable food production necessitates nutrient management strategies that reduce dependence on inorganic fertilizers. This preliminary study assessed the comparative effects of frass, cucumber leaf, and cow manure digestates supplemented with inorganic fertilizers on hydroponically grown basil. A randomized factorial design was used to evaluate plant growth, yield, and nutrient use efficiencies. Fertilizer treatments comprising 33% frass digestate, 33% cucumber leaf digestate, and 100% cow manure digestate produced statistically similar (p > 0.05) basil plant height and fresh and dry biomass yields. However, nutrient use efficiencies differed significantly (p < 0.05) between treatments. Cucumber leaf digestate recorded the highest nitrogen, phosphorus, and potassium use efficiencies, exceeding frass digestate by 26.5%, 156.1%, and 71.4%, respectively. Compared to cow manure digestate, cucumber leaf digestate improved nitrogen, phosphorus, and potassium use efficiencies by 59.1%, 162.5%, and 61.5%, respectively. These findings demonstrate that agricultural waste–derived digestates, particularly cucumber leaf digestate, can enhance nutrient use efficiency while maintaining yield, thereby offering potential to reduce inorganic fertilizer inputs and improve sustainability in controlled-environment food production. • Waste-derived digestates from cucumber leaves, frass, and cow manure were assessed as nutrient sources for hydroponic basil. • Cucumber leaf digestate resulted in the highest nutrient use efficiency and consistently greater basil biomass. • Digestate-based treatments reduced inorganic fertilizer requirements by up to 100% for selected macronutrients. • Converting agricultural waste into digestates offers a sustainable pathway for nutrient management in controlled-environment food production.