Molds are some of the most ubiquitous organisms on earth. Still, mold colonies can’t form just anywhere—they require a particular set of conditions to thrive. Here’s what mold needs to grow in your home.

Mold Spores

Fuzzy, slimy, or powdery mold growth on the wall, ceiling, or floor doesn’t just appear out of nowhere—there must already be mold spores floating around in the air. This is the case in nearly every environment around the world, both inside and outdoors. Dormant spores are usually harmless and imperceptible; it’s when they settle on a surface and start to grow that they become a problem.

Food Source

In order to keep multiplying, mold needs a source of energy. This may include any organic, cellulose-based material, such as wood, cardboard, the paper facing on drywall, fabric, carpet fibers, and even dust. Mold also readily grows on spoiled food, which is easy enough to get rid of by throwing the food away.

Warm Temperatures

Mold can’t grow in sub-freezing conditions. This is partly why food lasts longer when you freeze it. However, mold can still grow at refrigerator temperatures, which you are probably familiar with if you have ever forgotten about dinner leftovers for a few weeks. Still, mold grows more readily at or warmer than room temperature, which is why refrigeration helps food last longer, even if it’s not as effective as the freezer.


Mold prefers dark environments that are protected from ultraviolet light. As a result, mold often appears in hidden places, such as behind wall cavities, in dark corners, and under flooring materials, making it difficult to detect at times. This is why it’s sometimes necessary to schedule mold testing if you notice lingering musty odors, but you can’t see any mold growth.


Mold is a type of fungus, a unique group of organisms that are not plants, animals, or bacteria. Still, like all living things, mold needs oxygen to survive. Even a small amount of airflow is all that’s necessary to sustain a mold colony.


This is the key ingredient that encourages dormant mold spores floating in the air to settle on an organic surface and start growing. Moisture comes in many forms. It might be condensation on a cold windowpane that drips down onto the sill. It could also be a plumbing leak or wetness from a recent flood.

Even high humidity is enough to encourage mold growth. Your home is considered too humid if the relative humidity lingers at about 50 percent. Everything from cooking and showering to moisture seeping up from the soil in the crawlspace can raise a building’s relative humidity.

No homeowner wants to be told there’s mold growing in the house. However, the conditions needed to support mold colonies are present in most buildings, especially in basements and bathrooms where the humidity level tends to be higher. If you find mold growing in your home, call DKI Services. We are your source for reliable mold remediation across North America.