Conditions for Mold Growth in Houses
Besides oxygen and organic materials containing carbon to provide nutrients, the other main requirement mold needs to grow is moisture. You can find mold growing almost anywhere provided there is enough of a moisture source for it. Causes of Mold has more information about what causes mold in the home.

Mold problems cannot develop in houses unless there is a moisture problem. The moisture accumulation might be caused through humidity, condensation, or water intrusion from leaks, spills, floods, etc. Most molds only require suitable materials to be wet for 24-48 hours before they can grow.

Molds that can survive using only humidity as their moisture source are called Xerophilic, whereas other molds require an accumulation of moisture to grow. Indoors the best way to prevent mold growing is to limit moisture. To find out more about preventing mold in your home visit Prevent Mold.

Besides moisture, mold also needs the temperature to be right before it can begin to grow. Mold grows best in temperatures that we would consider warm, however there are some mold species that can even grow in temperatures as low as 2 degrees Celsius. If a mold colony's environmental conditions become unfavorable, instead of dying it can lay dormant until conditions become right again when it can continue to grow.