What is the best medium for R. gigantea?
You can use clay, perlite, and charcoal to make your own pot! Just make sure the bottom has good drainage holes.
I usually use several planting media for this type of plant, such as tree fern or cork, loose media, a mixture of coarse bark with a well-drained pot, some large pieces of charcoal, and rotten cow bones. This works really well!