In article , Inge Jones
writes
Can I fill my empty fern-bed-to-be with soil conditioner, or isn't that
enough on its own?

Ferns aren't greedy feeders. If it were me, I would fill the fern bed
with a bark based peat free soilless compost, like New Horizon.

That said, most of our fern beds were created from up-side down lawn
turves - it was what we had available at the time!

--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm