Help!! My mother in law has a phal orchid that has lovely green plump roots except for a few top roots that have shriveled from being out of the media. It's planted in a mix of sphagnum moss and bark. I repotted it earlier this year and it has since bloomed and grown a new leaf. Now, however, the leaves are dying rather quickly. She told me that they turn yellow and when one falls off, the next one up will begin to turn yellow in the following few days. She does fertilize when she waters about every week to two weeks depending on how wet the media stays. Any ideas on what's happening? She loves her orchid and I would hate for it to die!