The objective of this study was to investigate the effect of vermicompost, worm-bed leachate (WBL) and Glomus mosseae, an arbuscular mycorrhizal fungi (AMF), on growth of lemongrass (Cymbopogon citratus (DC.) Stapf). A response surface methodology, i.e. a three-level Box Benhen design with three repetitions and three blocks, was applied to optimize biomass production, essential oil yield and its composition. Application rates of Glomus mosseae were 0, 1 or 2 g plant^-1, vermicompost 0, 5 or 10 g plant^-1 and WBL 0, 10 and 20%. The AMF had no significant effect on the variables tested, but vermicompost had a significant effect on essential oil yield and WBL on essential oil yield, myercene concentration and shoot dry weigh (p < 0.05). It was found that lemongrass fertilized with 2.0 g G. mosseae, 5.0 g vermicompost and 20% worm-bed leachate would yield 0.797% essential oil of which 62.6% was citral.