Thanks for the thoughts everyone!
Seems the answer to the question "Have you ever tried to sprout Sundew seeds on pure ground coco fiber?" is a "no" huh? (Mine seem to be sprouting fine, I'm just looking for info from others.)
Let me know!
On pure ground coir? No. But then I never use just pure (100%) peat either. I have used a blend of ground coir and coarse sand or chic grit with no issues. Both Drosera and Byblis seeds germinated and grew just fine.
Can't recall the brand name but pick it up at herp shows. It comes in compressed bricks and is sold for use as bedding. Getting fertilizer free peat can be difficult sometimes and storage space is always an issue. The compressed coir takes up a lot less space and I don't have to worry about the mold issues that sometimes exist with keeping a moist bag of peat.
I have Burmanii volunteers I didn't even sow growing happily in it. I'd sowed venus flytrap seeds. They germinated, hung around for a bit, then died. Was going to empty the pot, except I saw LOADS of tiny burmanii seedlings. So I let them have the pot. I do nothing special for them. They don't get the best light, they get water runoff dripped on them from the pot above them... they don't seem to mind.
Earlier, when I wasn't that good at growing CPs (still not too good, actually) I had tried to grow drosera capensis and spatulata in pure cocopeat. Zero germination. But if it is any consolation, ALL my pots had zero germination then, so...