Ahhh... no good on D.regia, someone else can take that one but D.linearis is a local one here
You will need to stratify the HECK out of them seeds, a few months should be good. I would think typical peat/sand mix would do well for them, 50-50 mixed
D.linearis has a REAL short growing season, and needs a long, cold dormancy, most folks I've spoken with have had little luck with the species too far south, so some kind of fridge dormancy might be demanded depending on where you live, but outdoors year round is fine if it gets cold enough for long enough, I don't know any specific temperature range that they require, but they might be a bit tricky for you if you don't have sorta nasty winters
