How to Grow Castor Beans


Castor beans plants are exotic shrubs that can grow up to 10 feet in a single summer. They grow as an annual in cooler climates, an evergreen in warm climates and a giant in the tropics. The castor bean is made into useful castor oil, but the whole beans are extremely toxic to insects, humans and animals. Although the plants are beautiful, they should never be grown where children have access to them.

Step 1

Use a hoe to loosen a patch of soil large enough to accommodate the castor bean plant, which can grow up to 10 feet tall and 5 feet across. Although castor beans should be planted after the ground warms up in the spring, light frost won't damage the plant. Caster beans grow in any soil conditions but require full sunlight.

Step 2

Soak castor bean seeds in a bowl of warm water overnight. Soaking the seeds isn't necessary for germination, but will speed up the process.

Step 3

Plant the seeds 1 inch deep in the soil and water immediately after planting. Castor beans grown in groups will result in a natural, tropical appearance, so if you're planting more than one castor bean, leave at least 5 feet between each seed.

Step 4

Keep the soil moist during long, hot periods. After the seed is planted, it will require very little care. If you live in a cool climate, the castor bean will die with the first hard freeze, but it will re-seed itself the following spring.

Tips and Warnings

  • If the castor bean is grown where children have access, be sure to pinch off each bloom before the seeds develop. It's a good idea to wear gloves when working with a castor bean plant, as the foliage can sometimes cause allergic reactions.

Things You'll Need

  • Hoe
  • Bowl of warm water
  • Castor bean seeds


  • Ricinus communis
  • Castor Bean Seeds
  • Castor Beans
Keywords: castor beans, evergreen, annual

About this Author

M.H. Dyer is a longtime writer, editor and proofreader. She has been a contributor to the "East-Oregonian Newspaper" and "See Jane Run" magazine, and is author of a memoir, “The Tumbleweed Chronicles, a Sideways Look at Life." She holds an Master of Fine Arts from National University, San Diego.