How castor beans are grown
Castor seeds are not beans, and they carry one of the most potent plant poisons known.
- stations
- 3
- thing downstream
- 1
The short version
Castor beans are the oil-rich seeds of a fast-growing tropical shrub, 40 to 60 percent oil. They grow in spiny capsules that split open when ripe. The seeds are pressed for oil used in lubricants, coatings and nylon, and heating during extraction destroys the poison ricin.
-
Grow the tropical shrub
Castor is native to the Horn of Africa and now grows across the tropics. It is a quick-growing shrub that can reach the size of a small tree and cannot take frost.
-
Gather the spiny capsules
Each fruit is a spiny capsule holding large glossy seeds with brown mottling. Harvesting needs care, because the seeds are poisonous and can trigger allergies in sensitive workers.
-
Separate seed from capsule
Capsules are dried and hulled and the clean seeds are bagged for the crushing mill. The seeds are 40 to 60 percent oil, so a mill gets a lot out of each bag.
Worth repeating
- Castor oil is mostly ricinoleic acid, which makes it a sought-after industrial feedstock that costs more than ordinary seed oils.
- Roughly 270,000 to 360,000 tonnes of castor oil are made each year.
- In India, Pakistan and Nepal, grains are preserved by coating them in castor oil.
Where it goes next
Castor beans feeds 1 line directly.
Keep walking
Sources
Cite this page: "How castor beans are grown." Assembly Line, 2026-11-03. https://assemblyline.org/make/castor-beans