Question
I have several plants but the fleshly roots seem to be out of control.  Some of these are 8  inches long; others are quite large (diameter).  What causes unusual root growth?  What can I do to change this?

Answer
Hello H. E. Barkley,

What you have is not unusual with phalaenopsis and some other orchids, roots that seem to grow wildly on top of the pot.  These roots are normally referred to as aerial roots.  In my experience, when aerial roots begin to form and grow is an indication that the orchid plant should be repotted so as to contain the roots within the pot.  With that said, there is nothing wrong with allowing these roots to continue to grow outside of the pot as long as adequate humidity and moisture is available to prevent them from drying and shriveling.  As you have seen, these roots will grow seemingly out of control but they are just seeking a source of regular moisture.  

The choice is yours, whether to repot or allow them to continue to grow out of the pot.

Hope this helped.  Good luck and good growing.

Jim Kawasaki
San Jose, Ca.