Abstract Eggplant ( Solanum melongena L.) is a high-value crop with important nutritional and economic roles in tropical agriculture. However, its production faces challenges due to the escalating cost of conventional planting media such as cocopeat and the urgent need for more sustainable input alternatives. This study evaluated the agronomic and economic performance of alternative media like cocopeat blended with boiler ash, rice husk ash, and chimney ash combined with monosodium glutamate (MSG) as a potential biostimulant under fertigation systems. A Randomized Complete Block Design (RCBD) with 14 treatments and 10 replications was implemented at the Leaf Eternal Fertigation Farm, UMK. Growth and yield parameters including plant height, number of branches, leaves, days to flowering, fruit number, and average fruit weight were measured. Statistical analysis (ANOVA + Tukey’s HSD) revealed that the 1:1 mixture of cocopeat and boiler ash with 3 g L −1 MSG recorded the best performance, producing significantly taller plants (120 ± 2.5 cm), earlier flowering (34 days), higher fruit count (24.8 ± 2.1 fruits per plant), and larger fruits (233 ± 6.8 g). Media cost analysis resulted in a 64.9% cost reduction (from RM 3.34 to RM 1.17 per polybag). These results demonstrate the potential of integrating low-cost waste materials and MSG to enhance sustainable, cost-effective eggplant cultivation under fertigation.