Mold vs. Mildew

What’s the difference?


Mildew and mold grow everywhere in nature. They are nature’s recyclers and they break down old plant material. Mildew and mold can both grow in our homes. One can cause major damage and severe health problems. The other can cause surface damage and lung irritation. Neither is a good thing to find in our homes, but one is much easier to remove than another. How can you know which one you have? We will explore the differences in this article. 

What are they really?

Mildew and mold are both fungi. Fungi are neither animals nor plants. They inhabit a kingdom all their own. Fungi are spore producing organisms that feed on organic matter including yeasts, mildews, rusts, smuts, molds, and mushrooms. Fungi grow using filaments or hyphae that make up their bodies (mycellia). They digest organic matter externally before absorbing the nutrients.

You encounter fungi everyday in your food when you eat bread, drink alcohol, or eat blue cheese. Bread rises and alcohol is fermented using different yeasts. Blue cheese has a special type of mold (Penicillium Roqueforti or Penicillium Glaucum) that is purposely injected into the cheese, and allowed to grow, giving the blue cheese its specific flavor. Even though there are few molds that are beneficial to us, the molds that attack our homes are not.

How do they grow?

Molds and mildews are fungi that grow from microscopic spores that are everywhere in the air. Molds and mildews are found everywhere in nature, and are important for recycling organic matter (such as leaves). The recycling process they perform returns nutrients to the soil and is important for plants to grow. Molds and mildews need 4 things to grow: oxygen, moisture, a food source, and warmth. 

Molds and mildews differ in their method of invading and digesting organic matter. Mildews only grow on the surface of food sources. Molds grow inside of the food source. Molds can penetrate deeply into drywall, carpets, underneath kitchen and bathroom sinks, etc. 


It is possible that no matter how clean you keep your home, at some point you will have mildew. Mildew can be found anywhere that is warm and moist both inside and outside your home including: bathrooms, boats, floors, walls, ceilings, crawl spaces, and sheds. Mildew is much easier to remove than mold. Simply cleaning the area with baking soda and/or white vinegar should eliminate the mildew. Mildews generally do not cause lasting damage. However, their spores can cause coughing and allergic reactions. It is wise to wear proper protective equipment when cleaning.

Mildews can also be found in your garden growing on plants such as tomatoes, squash, crepe myrtles, and more.


Molds are much more difficult to eliminate than mildew in your home. Because they grow inside the food source (such as walls, carpets, etc.), and because molds cannot be easily killed, they must be completely removed from the area to stop their growth. Molds and mildews can cause allergic reactions and other health issues. Many molds produce MVOC’s or microbial volatile organic compounds and mycotoxins. These compounds are produced as the fungus grows and digests organic material. The MVOC’s can be toxic, and cause many health problems.

What can I do?

With mold and mildew, there are three steps to take for remediation and prevention.

  1. Clean what you can see. Baking soda, white vinegar, and hydrogen peroxide are excellent cleaners and can help remove the surface mold and mildew. Caution: do not mix hydrogen peroxide with baking soda or vinegar. For more information go to:
  2. Prevent new growth. Keep areas of high humidity dry by ventilating rooms such as bathrooms, kitchen, and laundry rooms. Dehumidifiers may be helpful.
  3. Get a professional inspection if you suspect the problem may be more than an isolated area. If you see areas larger than about ten square feet, or there is a musty smell you can’t identify, it may be time to call a professional. A professional mold inspection can ensure your problem is solved and not just covered up.

Remember, mildew is a surface dweller and easily removed. Mold grows inside of the food source (carpet, drywall, etc.), and can cause major health issues. If you clean up an area and the fungal growth comes back quickly, you may have a mold problem. Professional inspections can determine the true source of the problem and fix it. 

We’re here when you need us.

Call Branch Environmental. We’re experts not only at mold removal, but at determining and remediating the underlying causes. From hidden mold sources to major contaminants. We can identify exactly what is going on in your home and rid it of environmental toxins, often for good.