How to start castor bean plants from a seed

Updated July 20, 2017

The castor bean plant features spiky, red and green fruit growing among green, tropical leaves. This tree or shrub can grow 40 feet in height in warm, tropical climates. Grown for centuries for its seed oil, the castor bean plant thrives along riverbeds, streams, and anywhere the plant can receive warmth and constant moisture. Despite the name, the castor bean is not a bean at all. Growers attempting to propagate the castor bean plant from castor beans need to practice safety, since the castor bean plant and seeds are very poisonous.

Wear rubber gloves while handling castor bean seeds and any other part of the poisonous plant. Collect the spiky seedpods growing on the castor bean plant when they begin to dry and turn dark brown. Store the castor bean pods in a brown paper bag until they open and release the castor bean seeds. Each seedpod will contain three seeds, each within its own section.

Six to eight weeks before the final frost of the season, put on rubber gloves and remove the castor bean seeds from the brown paper bag. Drop the seeds into a bowl of water. Leave the seeds to soak for 24 hours before you plant them.

Treat the castor bean seeds with a fungicide before planting. Since each fungicide has different instructions for application, always refer to the included guidelines.

Mix equal parts vermiculite, peat moss, and coarse sand. Fill biodegradable planting containers, such as peat pots, with the soil mixture. Add water to the containers to moisten the soil evenly.

Remove the castor bean seeds from the water. Insert one seed 1 inch deep into each container. Keep the soil moist throughout germination, typically within one week.

Plant the germinated castor bean plants in prepared soil when temperatures linger above 21.1 degrees Celsius. Use a garden spade to create planting holes two times bigger than the castor bean plant containers. Fill the holes half with peat moss and half with the removed soil. Use the spade to blend them together and to create a depression in the centre of the hole to plant the castor bean and its container.

Plant the castor bean seedling, while in the decomposable container, into the prepared hole. Fill an average-sized watering can with water, and give the castor bean seedling a deep drink. Water the plant once a day, in the early morning or late afternoon.


Avoid preparing the seeds and growing the castor bean plant around children and pets. The plant's ricin content is deadly.

Things You'll Need

  • Rubber gloves
  • Dried castor bean seedpods
  • Brown paper bag
  • Bowl of water
  • Fungicide
  • Vermiculite
  • Peat moss
  • Coarse sand
  • Biodegradable containers
  • Garden spade
  • Watering can
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About the Author

Dustin Alan began his writing career in 2000 where he was began writing for “Times Record." His work is featured in “Arkansas Home and Garden," “Green Thumb," Home Step Ahead and DIYImprove. Alan attended Arkansas State University and graduated in 2000 with a Bachelor of Arts in English.