Vanda question

[Alicia Moïse]

Live in central OH and keep several vandas in my conservatory on a humidity tray. The leaves turn yellow and fall off then it dies. What else do they need? Dendrobiums, cattelayas, phalenopsis live in the same room and are thriving. Varigated papheopedolums have healthy foliage but don't bloom. Any suggestions?

[tennis maynard]

I also live in central Ohio and grow indoors during the winter, in three growrooms; my humidity is usually too low there. You don't say how much light the vandas are getting or in what/how they are potted. I grow mine potted in plastic pots with large bark mixed with sponge rock #4 (the largest I can get) and water them as often as everything else, usually every 4/5 days or so. They sit immediately under the 400W light. I have even bloomed a few:

Perhaps yours aren't getting enough water. Vandas are actually waterloving plants; they just don't like to be too wet around the roots at night.

Don't know if you're a member of the Central Ohio Orchid Society

but there are a lot of long-time growers there who are more than happy to help out with whatever insight and experience they may have, and even more newer growers full of excitement and questions.

Of course there are other possible problems: thrips, disease, etc. Hard to say for sure without more info and seeing the plants.