I posted about these guys way back- I started the seeds from a cross that I made over 3 yrs. ago. It takes the seeds 2 years to mature. I kept the seeds until after we moved, and started them in November of last year. A lot of experts said they couldn't be grown from seed- Hmmm.... Where did they think they came from
I just use regular potting soil. Peat, a little sand and some pearlite. They like to be treated more like succulents than cactus. They aren't really cactus as the common name implies. They like to be a bit pot-bound also. I have a couple more pods developing on my larger plants from this past Dec. They'll be ready in a couple of years!