Julia, welcome to OrchidTalk!!
Well, when it comes to Epidendrums, truely, it all depends. Do you know what kind you have? There are over 1000 species. These may be epiphytic, terrestrial or lithophytic. So, it is difficult to make generalizations. (For me anyway). There are a lot of experts like Gin and Orchid-man, here on the Forum who can do better, especially if you can post a picture of the orchid. Joe