Hi there, i grow castor bean every year, it self seeds and right now the babys are just starting to emerge! Its very easy, i would just poke a few in the ground where ever you would like them, water and wait about 1 week or so, the come up very fast and also grow very fast!

Bluesmap. CB is fairly simple starting in pots. Either purchase a Seeding Mix or make your own.
You can either use Peat Pellets or small plastic pots, 'to start.'
Insert 1-2 seeds per pot..Water well. Cover with plastic, but cut straight lines of plastic for ventilation.
Germination is fast. After seeds sprout, remove plastic. Place in a sunny spot, indoors. Water, when soil starts to feel a little dry, not muddy.

Once babies reach 8" or more, more is better, plant in your garden, in a sunny spot. Good luck, Toni