[Ellen]

Just saw this post - wish I could have responded earlier to reassure you that you're not mistreating your Odontoglossum. I have this very same orchid, and it seems really tough. I divided it earlier this year and now have three plants growing in exactly the mix you describe - fine bark/perlite/charcoal. It seems to be doing fine, putting out new growths and roots after an extended sulking period, probably brought on by exposure to near-freezing temperatures right after I divided it. It had previously been in a sphag/perlite mix, and was doing fine in that, too. I don't think it matters much what it's in as long as it gets watered enough and has fairly decent drainage. I have mine outdoors, but it was in the GH over the early part of the winter, and in the house when blooming, and it did fine in all those places. Your pic of the roots looks fine. I don't see any obvious problems. The roots of oncidium alliance orchids will sometimes become stained from the medium they're growing in - brownish color is no problem. This type of orchid is a water hog - if it has good drainage, it will take a lot of water. I doubt that your orchid has any serious problem, so just relax and let it do its thing.