What Mold Needs to Grow
- Moisture is the one thing that every mold requires for growth. Although as many as 400,000 types of mold exist, they all share this common need. When mold spores settle on moist surfaces, the germination (growth) process can begin. Moisture alone is not sufficient, however. The moisture must be consistent, so mold seldom grows in an area with ample sunlight, heat or air circulation, where moisture evaporates. Mold grows best where moisture can remain for extended periods of time.
- Though any source of moisture can potentially breed mold, you must remain especially cautious of high humidity, flooding and any source of standing water. If humidity exceeds 60 percent, your mold risk increases, according to the Centers for Disease Control and Prevention. You can measure humidity using a humidistat (available in home supply stores), and you can reduce humidity using a dehumidifier. Standing water (such as a puddle beneath a leaking pipe) and flood waters present a problem, because water has no way of evaporating quickly on its own.
- Many mold varieties, such as Stachybotrys chartarum (black mold), grow best on cellulose materials. Cellulose is found in plant cells, and it appears in paper, wood, cotton, wall boards, upholstery, carpeting and fabrics. Mold is far less likely to grow on surfaces like metal and concrete.
- In addition to the presence of cellulose, mold requires absorbent, porous material to grow effectively. Moisture evaporates more easily on nonporous material, such as metal and glass. Porous materials, on the other hand, can trap moisture, which allows mold spores the ample time they need to germinate.