In the right climate they are garden plants so it doesn't matter what you pot them in. They will grow and flower provided you give them enough sun.

I have some "dwarf" named hybrids that are growing with my laeliinae hybrid collection, they are potted in a treated pine bark, coconut chunk, diatomite mixture.

I realize I'm in a different climate, but I have two Epis that I grow indoors... one is potted in a fast-draining potting soil/mix, and the other is in orchid bark... both are growing nicely.

Both came to me from Florida, and my friend told me to put them in a regular potting mix, which is how she grows them. I thought I'd try one in bark, to see how it would do... so far, so good.

My observations are that reed-stem Epis are fairly forgiving and adaptable, and I think the medium can be adjusted to suit conditions quite easily.

The only problem with them ( Reed stems in the right climate) is size. Some of the older types will grow into big scrambling monsters that bear long racemes that could end up with an in-flower plant being as much as five or six foot high.

Orchid growers did not even bother to bench them at meetings etc. Renewed interest in them as breeders have tried to reduce the plant size to manageable proportions.

The garden plant down the backyard has endured an annual temperature range of 1 to 40C plus. They are as tough as nails.

For my reed-stem epidendrums, I typically use the following mixture:
50% potting soil (whatever brand is on sale)
25% perlite
25% crushed charcoal (about 2x the size of the perlite nuggets).

I change it up every now and then, depending on what is cheap and readily available at repotting time. I just cant find myself spending money on premium potting materials like fir bark on these immortal plants.

I even grew some in pots with groundcover wood chips. Not orchid bark, but the ones with large nuggets that landscapers use to mulch around trees.

I used to have a lot of them. But you know something is not right when I was actually using Round Up on orchids...

I don't really neglect mine, per se, but I certainly don't hover over them, either! Growing in an east window as they do, I doubt they'll get as big as they would if I lived in a tropical climate. I'll probably never need to use a weed control product on them!

They don't grow that fast for me, and so far, have been quite manageable. The Epi has been the perfect first orchid for me... not at all demanding, and easy to grow. (I don't count the Phal I killed as my first orchid!)

I grew them in sphag and bark. To get them to flower they need tons of sun. I used to hang them in full sun all summer from my fence.

I'm determined to find a good outdoor summer spot for my plants next spring... this year, I didn't have a decent place to keep them. But I know they'll need more light, and by next year, they should be old and big enough to bloom. A summer outdoors should help immensely.

Personally, I am sure everyone will boo me for saying this, but I grow my huge 3Gal pot of epidendrum radicans in mushroom compost and they are over 18" tall. 2 canes have already bloomed and more should be coming soon. My grandmother planted the radicans I gave her in southwest florida and over 5 years the canes grew 12-22 in flower stems which also grew keikis and those sent roots to the ground for support and moisture and now the plant is at least 3 feet in overall height with a new layer of growth on top of that so they can be at least 3-4 feet high and that is planted next to a retention pond in basically southwest florida sand. I also have a few other epi's growing in compost soil and they must like it with roots growing down over the pot and all. Ironically, those have not grown big enough to flower yet but they have grown stems about 12-14 inches high so I'm hoping.