Hoya seed cannot be dried and stored like many other seeds because the viability over time is very short. The main way to get Hoyas is as established plants or as cuttings.

Mike

It's also said to be very short-lived. One is supposed to plant it while the seed is quite fresh. I think that's why one doesn't see it offered for sale.

I had a friend here who had some seeds a few yrs. ago, but don't recall seeing any around here for a while.