The present study investigates the effect of nano-Fe₂O₃ particles as a micronutrient on the growth of plant seedlings of Mung (Vigna radiate) and Gram (Cicer arietinum) using the plant agar method. The laboratory experiment was carried out in the test units comprising a petri dish and plant agar medium. The plant agar medium used acts as a false soil that supports the seedlings for germination, prevents precipitation of water-insoluble nanoparticles and eliminates the possibility of any nutrients from external sources other than the nano-Fe₂O₃ particles. Each test unit containing agar media was treated with nano-Fe₂O₃ particle suspension at different concentrations. The effect of nano-Fe₂O₃ particle dose-response on root and shoot growth of the seedlings, as well as on biomass assay, was examined. The results showed that among the various concentrations of nano-Fe₂O₃ particles studied, a good agronomic value over control was observed only for certain optimum concentration i.e., 50 mg/L for mung and 5 mg/L for gram seedlings. Beyond this dose limit, the seedlings showed retardation in their growth characteristics, indicating phytotoxicity.