Question
I am working with several commercial growers in Central FL.  Some of the Vandas I am looking at have an unusual yellow chlorosis developing from the tips down.  Could I send you a photo to get your opinion.  unfortunately, some of the ideas floating around don't seem quite right to me.

Thanks,
Chris

Answer
You may send me a photo if you wish.  I grow only a few vandas. If you haven't seen Martin Mote's book titled "Vandas", Appendix A of his book lists several possible causes of leaves turning pale yellow. Martin has been growing vandaceous orchids for over 40 years in the south of Florida.  The five causes he lists are: 1) Too little water, 2) Too little fertilizer, 3) Trace element deficiency, 4) Too much light, 5) Too hot. Some additional information which would be useful in making a diagnosis: Where are they grown?  Is there good root or root-tip growth? Do they flower Okay?  Is the color change on all leaf tips or primiarly on lower or upper leaves?  Are these young plants or mature plants?

You are fortunate to have available some master vanda growers in the south of Florida who would have more first hand experience in thie type of orchid.  Another premier vanda grower in the south of Florida is Robert Fuchs in Homestead.  His E-mail is [email protected].