OK...have been soaking a sample of my older seeds since Sunday night...they floated when I put them in, but now have all sunk to the bottom of the container...will be planting them up tonight and see what happens...
About 2/10 seems to be par for me. Here's two from Inyo co.
Don't be surprised if nothing comes up. Here is a pot of the supposedly easier var xeranthmoides drying out for another go in a few weeks. This seed is possibly too fresh.
And here is E. parryi where nearly every seed came up.
I got 3/10 on E. xeranthemoides, but also nearly 100% on E. parryi. Some Echinocactus are easy, so we can't expect frustration from all of them, though E. parryi seems kind of slow.
My previous attempt with var xeranthmoides sprouted very well. My database says 20 seeds but I have about 20 seedlings so there may have been more than that. Here's half of them.
I've had nearly 100% on Meadview intermediates between polycephalus and xeranthemoides from habitat seed collected a few months earlier, so fresh seed seems good on at least some of these guys.
If you squint, this picture looks like some bizarre full-sized landscape. The moss is like grass/ground plants and the seedlings surrounded by "boulders" are weird trees.
Great picture!
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.