Oncidium Brown/yellow roots

[silken]

If it is new bark, its good to soak it for 24 hrs before potting as it does not hold moisture too well for the first few months. So if it was new and especially if it wasn't soaked, you might need to water more often. Run a good amount of water thru or set the pot in a pail of water up to the roots (not the crown) and soak for a couple minutes. Drain very well so it doesn't stand in water afterwards. If there are lots of roots sitting on top you can mist them daily or every few days. Just make sure the centre of the pot is nearly dry before watering again. A little dry is better than too wet in my opinion. also make sure you do not mist water into the crown of the plant as it could develop crown rot.