@Richard Ellam Real Seeds have seed saving info: https://realseeds.co.uk/seedsavinginfo.html I watched a video a couple of days ago about hugelkulture. I'm thinking of creating some beds myself. I have plenty of rotting wood to use! But prority is to fininsh erecting and glazing a 50 x 18 ft greenhouse. Let me know how you get on with the hugekulture.

I tried sea kale once without much success. Perhaps growing them in pots was an issue. I do grow smooth leaved kale annually (varieties Sutherland and Madeley). Personally I prefer the texture of smooth leaved kale to curly kale. I prefer growing kale for the shoots the spring following sowing - just like purple sprouting broccoli (PSB). Outdoors kale flowering shoots appear from about early April to middle of June. I've found kale to be very frost hardy, unlike PSB which can die off in periods of more severe frost. Once the shoots get to small to pick allow remaining shoots to flower and go to seed. They are very prolific seed producers. Although I haven't tried it yet, I'm sure surplus seeds could be sprouted like alfalfa.