Sweet flag (Acorus calamus L.) is known for its pesticidal and seed-quality–enhancing properties due to its essential oil richness. The study quantified compounds in sweet flag rhizomes and assessed their effectiveness in improving field bean (var. HA-5) under field and laboratory conditions. Essential oil was extracted by hydro-distillation and quantified using gas chromatography (GC). A foliar spray experiment was conducted using a randomised complete block design (RCBD) to assess the effects of sweet flag rhizome powder, rhizome oil and a chemical check on crop growth, pest and disease incidence. A 9-month storage study was conducted under laboratory conditions to evaluate seed storability. The essential oil yield aveaged 0.29 % and was dominated by β-asarone. Results indicated that moderate concentrations of sweet flag rhizome powder and oil significantly improved seed emergence, plant growth- and plant stand, while also reducing pest and disease incidence. Seed treatment with rhizome powder at 10 g kg-1 consistently maintained higher seed quality during storage. Sweet flag rhizome-based treatments showed strong potential as eco-friendly options to enhance field performance and seed storability.