How to Propagate Castor-Oil Seeds

Mix equal parts mature compost and nitrogen-rich potting soil. Fill a terra cotta pot three-fourths of the way with the soil-compost mix. Do not pack down the soil so the roots can grow and spread easily.

Fill a paper bowl or cup with lukewarm water. Place your seeds into the water and allow them to soak for 24 hours. This will soften the outer coating of the seeds. Wear gloves while handling the seeds and throw away the bowl or cup after use. Throw away the gloves or rinse them thoroughly with a garden hose before washing them to avoid spreading ricin.

Dig a 1-inch-deep hole with your fingers and place a single seed inside. Cover the seed with 1 inch of soil and water until the soil is wet but not soggy. For a more tropical look, plant several plants in one container 6 inches apart. You will need a very large pot for this.

Place the pot in a warm, sunny area. Castor-oil plants do not tolerate temperatures below 65 degrees Fahrenheit. Water the plants when the soil becomes moist, but not dry.

Fertilize the plants with compost each month by spreading compost in a 1-inch layer around the base of the plant. In warm areas, you may transplant your castor-oil plant outdoors when it reaches 6 inches tall. To keep the castor-oil plant from self-sowing, clip the round, purple fruits that form in late summer from the plant and discard them.