Is it presently growing indoors? How is it mounted? How old is it? What species is it? Does it have any shield fronds?

You can use a clay pot or orchid pot (with side slits) if you like (breathe better but dry out quicker). (I use basic plastic.) I definitely suggest a soil consisting mostly of sphagnum moss, peat, and wood chips. If you lived in Florida you could grow it on wood, but Calif. is way too dry for that. You could use loose orchid mixes but I would work a significant bit of sphagnum/peat into the mix. It would benefit from a summer outside in filtered sun, mist often. They're easy ferns!:)

I would shake off any loose dirt but leave whatever dirt is snuggled in the roots. Then surround it with sphagnum moss to fill the basket. They seem to like being sideways as though they're on a tree trunk. You can soak the whole rootball every now and again but they REALLY love being misted, I mean like every day! Good luck! I've had mine for a couple of years and I love it!

Ahhh, Australia... How do you keep it hydrated there? I have several staghorn ferns, and I put some wet moss around a piece of wood (no salts in the wood) and then I used copper wire to secure the plant to the whole thing. I kept it in the shade, which, in our zone 8b in south Alabama USA is quite humid. I do not fertilize it at all. I do spritz the leaves, which do NOT like to have dust on them, and neither do they want you to remove the fuzz. A healthy leaf is a fuzzy leaf. What sort of normal humidity do your ferns have? And what size is this plant you are having trouble with? Probably putting some compost tea in a tub/container and immersing the plant in it will help to remove all the overdose of chemicals for a fresh start. Then let it drain. Let me see if I can find a shot of my young plants, some of which even started new babies within the moss before they had fully attached to the wood board. In the summer, I hang my young plants by chains from the tree limbs outdoors, in the shade of course. One thing I discovered was SCALE on some of them, when I had a scheffelera near by. I finally got rid of that scale magnet, and cleaned up the scale on my staghorns, and now they are all doing nicely. Good luck with your young plant. and here are the babies and a good view of the moss. No soil used at all. Keep the moss damp, not soggy.