The castor bean plant (Ricinus communis) is an annual native plant from North Africa that has escaped cultivation and now grows wild throughout the world. Because the large, fast-growing plant has broad tropical-looking leaves and decorative red seed coverings, it is a desirable landscape plant. However, all parts of the plant are highly toxic and only a few seeds need to be ingested to kill an adult human and only one seed will kill a child. Therefore, caution must be taken when harvesting seeds in the fall to plant the following spring.
Find a castor bean plant in the fall that is healthy and is producing seed pods. The seed pods are covered with dark red or purple hairs and look like they should contain round seeds about a half-inch in diameter. Look for seed pods that are beginning to split--these have seeds ready to harvest.
Wearing gloves is absolutely necessary for your safety throughout this task. Put on your gloves, and pull the splitting seed pods from the plant. Break the seed pods away from the seed and put the clean seed in a dry paper envelope. Collect as many seeds as possible from splitting pods. You may need to return to the castor bean plant several times over a few days to gather more seeds as the pods split open.
Store the paper envelope with seeds enclosed in a dry, cool (60-75 degrees F) place away from children or pets so they do not have access to the seeds. You do not need to refrigerate castor bean seeds.