Persistent white mold on Epidendrum roots

[Johnny-T]

Ok, thanks for the responses, so I repotted the epidendrum (only bark chips), watered it and will try to provide better air circulation. But I am wondering, why is this orchid so prone to mold, it's not like the sphagnum moss was too moist for longer periods - after a week it was completely dry. None of the other orchids had problems with mold thankfully.

Just to be sure, what is a good watering schedule for epidendrums? Is it ok if it dries up and maybe stays dry for a few days?