Peas are members of the legume (Fabaceae) family. Through a symbiotic relationship with a soil bacterium (Rhizobium), peas are able to “fix” atmospheric nitrogen in nodules on their roots.
Peas will grow and produce a crop without inoculation. However, inoculation with a nitrogen-fixing bacterium may be beneficial if peas have not been grown in the garden in the past. Pea inoculants can be purchased at garden centers and from mail-order catalogs. Inoculate pea seeds immediately before sowing. Place a small amount of the pea inoculant into the seed packet and shake.