Causes and Cures for Mold and Mildew
Growing on House Plant Soil

February 1, 1998 Lorimyn@aol.com wrote: There is mold growing on top of the soil of some of my houseplants. I live in a very humid climate. What is the cause and how can I get rid of it? THANKS!!
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Mold is of a type of fungus, mildew is also a type of fungus and is sometimes used interchangeably. I know very little about either, and I was unable to find much help in my reference books or on the internet. Because there are so many different types of fungi it is difficult to know how to fight an outbreak. Mold propagates by spreading a millions of spores, which travel through the air. Mold spores are everywhere, and can grow on almost any organic material. Mold likes high temperatures (mid 70°F), high humidity, darkness, and stagnant air. When mold is discovered check to see if it is active (soft, fuzzy, smears easily) or dormant (powdery, easy to wipe). If it is active and it is in single plant, consider withdrawing it from the collection, and carefully remove and replace the top inch of soil from the pot. If it is in the dormant stage, allow the soil to become quite dry, then brush off the spores, working outdoors and (if possible) with a fan blowing the spores away. Some varieties of mold are toxic to humans, so please use great care. Wearing rubber gloves and a dust mask are not unreasonable precautions. How to combat mold There are fungicides on the market that will kill the mold, check with your local nursery or garden center for an appropriate one, and use only according to directions. To help prevent a repeat occurrence, move the plant to brighter light, keep the soil on the dry side, (during the winter months, this is a good idea, anyway) maintain moderate temperature and humidity, and provide good air circulation. I wish that I could be of more help, but I think you can easily defeat the mold.