I just had a nice woman from Ohio contact me about selling her Reddit group Hoya seed, and since I frequently get request for Hoya seed I thought that I would share my response here:
Seeds – Sometimes I go years without pollination that produces a seedpod and other times I will get lucky and I might get 3 pollinations in one summer, but it is completely not predictable. I have never managed to purposely bring about a pollination. More on seeds: Except for Hoya papaschonii which seems to self pollinate regularly, and the seedlings are pretty much true to the parent, seeds are generally not a good way to increase your Hoya stock. Many of these seedlings are weaker, not true to the parents, and should never be sold or traded without being labeled a seedling. Sometimes you need to plant 50 seeds to come up with a couple of good plants as recently happened to me with both multiflora and ruthiae seed. Also, raising Hoyas from seed is a very slow and laborious practice, and not at all like starting, let’s say, tomatoes from seed. The best and only reliable way to propagate Hoyas is from stem cuttings so that you really know exactly what you are getting.