The key to mold control is moisture control. If mold is a problem in your home, you should clean up the mold promptly and fix the water problem. It is important to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth. Why is mold growing in my home? Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter, such as fallen leaves and dead trees. But indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air.