Layer the bottom of a large container with landscape cloth, available at garden centers and home improvement stores.
Prepare the soil in the container by combining gardening soil, peat moss, and garden inoculants, bacteria culture that helps fix the nitrogen level in the soil. You can find this at garden centers.
Sow the seeds in the pot, spacing the seeds 3 inches apart and 1 inch deep. You can fit up to nine plants in a container with a 12-inch diameter.
Water the soil until it is moist. Check the soil often, and water when it dries to a depth of 2 inches. Typically, an inch of water each week is sufficient.
Add water-soluble fertilizer once per month. Follow the manufacturer's directions for amounts per the size of the container.
Harvest beans after 45 to 65 days.