Question
Have a vanda that grows new leaves, but no new roots.  It has only one large root.  How to make it grow roots?  Thanks

Answer
Clara, I don't know how you are growing it.  Vandas like lots of humidity and moisture.  I prefer hanging baskets where the plants can get lots of air movement. If the plant is so potted, you may hang its basket in a tree and water it daily.  You may soak it in a bucket in water until the aerial root(s) are green.