image showing example of mold vs mildew
On the left: typical example of mildew on tile. On the right: black mold growth in the bathroom.


Both members of the Fungus Kingdom, Mildew and Mold are very similar microscopic organisms which thrive on organic matter in moist, warm, dark environments. In fact, often mildew and mold are terms used interchangeably, and although they will both create a strong, musty odor and both can cause adverse health reactions for humans, they do have a few visible differences.

Caused by mold fungi, and transported by carriers such as pets, clothing and shoes, mildew is usually a smaller, smooth surface growth that is white or grey in color. Mildew can often be found on damp surfaces, like bathroom and basement walls, but it will also grow on plants, metal, soil, or any surface that offers moisture, dark, and heat. Mildew is usually easily treatable with homemade or store-bought cleaners.

Found most often on food, mold is black, blue, red or green and grows in the form of hyphae, or multi-cellular filaments, which means that it will appear to have texture, unlike smooth, flat mildew. Mold spores spread through the air and will attach and grow on any organic surface in a moist area, such as damp clothing, floors, and furniture. When you can see mold, it is usually a sign of a larger infestation that usually requires professional treatment in order to protect your home and health. Usually you will find mold on cellulose materials, such as paper and wood, but mold can also grow on glass and metal as long as there is a bio film on the material on which the mold can feed.

In the world of horticulture, mildew is very specific to fungi commonly referred to as downy mildew and powdery mildew. Powdery mildew can be found on flowering plants such as roses, and downy mildew grows on plants such as potatoes, grapes, and tomatoes.

Often, when referring to toxic mold in a home, we are referring to both toxic mold and toxic mildew. Although they do have differences, as explained above, for the sake of ease, we will refer to them as toxic mold throughout the Mold Badger site. You can learn more about toxic mold and mildews in your home on our Most Common Types of Mold page, toxic health reactions to both in our Black Mold Symptoms section, and removal and prevention for both in our Mold Removal section.

Badger Tip: Mildew needs the proper conditions to grow: any organic surface, warm temperatures, and moisture, either from humidity or a leak. To avoid mildew growth in your home, keep your humidity below 60%. Running your air conditioner is one way to remove moisture from the air and keep your indoor temperature low – preferably lower than 77 degrees, which is the optimal warmth for mildew growth. Use an inexpensive humidity meter to check your levels. If your A/C isn’t keeping your humidity low enough, consider purchasing a dehumidifier.

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