I have one vanda is really thick roots, the leaves look pale with soft looking winkles. I have read that vanda's are heavy feeders but I don't know how to feed it. I water or mist it every day and since I live in the southern US I am going to hang it outside.
The simplest way to fertilize a vanda is to get one of those little plastic hand spray bottles from Home Depot for less than $5. It holds about a quart of water so that's about 1/4 of a gallon. Buy a small container of water soluble fertilizer. Home Depot and Lowes probably have fertilizers designed for especially for orchids. Don't buy the Bloom or Bloom Booster fertilizer. Put 1/4 teaspoon of the fertilizer into the hand sprayer filled with water and spray it on the roots once a week.