The current study was undertaken to investigate the mass multiplication of different combinations of three arbuscular mycorrhizal isolates (Glomus, Acaulospora and Scutellospora) in three different substrates (Soil:FYM, Soil:Vermiculite and Soil:Sand) in terms of root colonization (%) and spore quantification using lemon grass as host plant. Lemon grass raised in Soil:Vermiculite treated with the combination of all three isolates (ie., Gl+Ac+Sc) recorded the highest root colonization (99.99%) and maximum spore density of 121.10 per 10 g of soil. Root colonization and spore count were high positively correlated with each other (0.996). Thus, the present study might be significant as it suggests an economical as well as eco-friendly highly effective inoculum.