- In some ways, castor bean plants use the same sexual process animals do, in that they need male and female contributions to combine in order to make seeds, called "beans." Reproduction begins when a mature plant grows male and female flowers on a long spike-like branch. The male plants are on the bottom and the female parts are on the top of this spike.
- The male plants contain pollen while the female plants will eventually grow into fruit once they get the male flower's pollen into them. The wind shakes loose the male flower's pollen and it drifts up to the awaiting female flowers.
- The female flower then grows a fruit, which looks like a forbidding spiny shell. This is a seed pod to hold three seeds, even though many gardeners will call them "fruits." When the seed pod dries, it falls out of the female flower and drops on the ground, splitting open and releasing the seed. It is these seeds that get harvested.
- Those seeds that aren't harvested eventually turn into seedlings. In order to accelerate this process, the seeds have a sponge-like end called a carnuncle to help soak up any moisture that falls onto or around the seed. They grow into the adult plant, which grows the flower-covered spike and the cycle begins again.
