Select two or three bean plants in your garden that you plan to save seeds from. Allow the bean pods on those plants to remain on the vine, ripening until they are brown and dried. The seeds will rattle in the pods. This process may take up to a month beyond when you would normally pick them.
Pick the pods and spread them in a cool, dry location to dry for at least two weeks. Once dry, remove the seeds from the pod, or leave them intact. The most important factor in storing seeds is moisture. When moisture is adequately removed, bean seeds remain viable for at least one year, and up to 10 years under ideal storage conditions.
Store the bean seeds in an airtight glass or plastic container in the refrigerator. Add 1 tbsp. powdered milk, wrapped in a piece of cheesecloth or napkin. The powdered milk absorbs moisture from the seeds, ensuring quality. Label the bean seeds with their names and the date stored. Storing bean seeds in the refrigerator also increases their storage viability.
Before planting a garden the following spring, check for germination rates. Lay 12 beans on a damp paper towel and cover them with another paper towel. Mist the towel to keep it moist and wait one week. Most of the seeds will begin sprouting if they are viable. If the seeds fail to sprout, buy new seeds for best results.