Expert: Wayne King - 10/21/2009

Question
I use clear plastic pots for my lady slippers and phals. There is a white sugary looking substance that grows in some of the pots. When I repot, there are some webby growths also. The bark smells somewhat like mushrooms leading me to believe it is a fungus. What is it and does it hurt the plant?

Answer
Ann, thank you for your question.  It sounds as if you need to repot in fresh orchid potting mix. Just as important, you are keeping your potting mix too wet.  Do not let the pots stand in water.  Your potting mix is either constantly wet or you are using a potting mix that is broken down and/or is not permitting much air movement through the mix.  If you allow your plants to dry out between watering, you should not experience mold growth.  I think that "sugary" substance is a mold which is supported by your statement that the bark smells like mushrooms.  The webby growth also sounds like fungal mycelia which woud only occur if the potting mix is kept too wet.