Castor plants (Ricinus communis) are fast growing and can give an ordinary backyard garden a tropical look in a matter of weeks. Castors are native to northeastern Africa and have become naturalized in many tropical areas where they grow to 40 feet high. In cooler climates, gardeners grow them as annuals that can reach 8 to10 feet with sufficient sunlight, heat, water and nutrients. Green and red are the most popular castor foliage colors for backyard gardeners.
Choose the location in the garden where you want your castor plants to grow. Select a spot that receives many hours of direct sunlight during the summer growing season. The ideal spot will give the plant some shade when the sun is at its peak.
Estimate the number of castor beans you will need to fill the spot. Base your calculation on each bean producing one plant that will grow 8 to 10 feet high and 3 to 4 feet wide. Prepare a few extra beans to serve as replacements in the event of failure during the early stages of the process.
Soak your castor beans for 12 to 24 hours, six to eight weeks prior to the last expected frost in your area.
Place softened castor beans 1/4 inch down into moist soil and set in a room where the temperature is approximately 70 to 75 degrees Fahrenheit. Make the soil from "equal parts of compost or even topsoil, peat and filler, or of peat and filler, provided this mixture is loose, fine and crumbly," according to recommendations in The Grow'Em Plant Propagation Database.
Wear gardening gloves and transplant seedlings into the garden in fertile, well-drained soil, when all danger of frost has passed. Space the castor plants 3 feet apart.
Water the castor plants regularly as they establish themselves in the garden. Water the plants to keep the soil evenly moist during the growing season
Direct Sow Method
Choose a day, after all danger of frost has passed, when you want to plant your castor beans. Soak the castor beans in water for 12 to 24 hours.
Place the castor beans into fertile soil in a sunny location. Space the beans 3 feet apart.
Water the seeds thoroughly until they are established. Water during the growing season to keep the soil evenly moist.