Complete orchid growing information
Cork or tree-branch mounts work well. The plants will grow on tree fern, but the thick roots will get badly damaged if you have to remount them. It’s a good solution to use Growing Medium A for all-purpose media.
Brassavolas can easily be divided like Cattleyas in spring or when a new flush of roots just becomes visible. If you pot them, use 3-inch pot for an average-sized division with a well-drained mix like medium-grade fir bark, lava, or pumice.