Staghorn ferns do need potting soil beneath their shield or roots but the trick is to make a mound of potting soil an inch or two deep, set the fern on top then fill in around the soil mound with moss. You keep all the moss in place with fishing line and nails. The nails are pounded into a board in a circle the same size as the base of your fern. The potting soil goes into this circle of nails. The fishing line and moss secure the potting soil and fern to the board. Work with the board lying flat on a table and mist the moss and soil well. Let the plant root laying flat for a few weeks before you hang it up on a wall. Like most ferns, shade and moisture are important for healthy growth. Keep growing, Marianne Binetti