Question
Hello, I have two otherwise healthy phals - but the top of the root (nearest to the plant) are developing brown spots/patches.  It's making the root look woody.  The bottom of the roots are fine.  I was thinking that perhaps I should stop watering from above?  Or is there something more sinister happening?  Thanks!

Answer
Heather, thanks for  your question. It would be helpful to have a picture.  Lacking that, it sounds as if you have a thin layer of corklike (ie woody) tissue starting to cover the velamin (ie spongy outer root covering).  While this may be unsightly, it is there to protect loss of moisture from the velamin and is normal. One thing you can do is to add orchid potting mix to cover that portion of the root.  Since you water from the top (which is fine), the potting material on top will tend to get wet and protect the previously exposed root from losing moisture.

In nature, orchid roots grow in a humid environment.  When portions of an orchid root are exposed to drier air, they usually have two mechanisms to prevent the loss of moisture from the root.  One method is to develop a protective sheath or covering.  Another method, often seen in aerial roots, is to stop growing and cover the green growing tip with a layer of cells.