[Cynthia, Prescott, AZ]

Get a package of mosquito dunks from a garden supply or home center, or maybe a hardware store. These have organisms that attack the gnat larvae that live on the fungus growing on the organic material in your mix. Break off a small piece and put it in the water you are using to water your orchids with every time you see them return. A treatment should be good for several months. And you can use this on your house plants where the soil type is just right for the gnats. I would not take the approach of repotting, too much stress on plants that don't really need repotting yet, not to mention that repotting for some orchids really should be done at the right season.