When most people think about where mold grows, they picture hot, humid, and dark corners where all the creepy crawlies live. They rarely picture snow outside and freezing temperatures. This article will help explain that mold does not fly to Florida with all the snowbirds. It is as much of a problem during the winter months as it is during the summer. First, a little background information. Three basic components are required for mold growth to occur. 1) Mold spores, 2) carbon material (food) and 3) moisture. Of the three, moisture is the one that causes the problems but luckily can be controlled. You may be asking yourself, if moisture is the problem and the air is usually dry in the winter, why is mold a problem in the winter. Winter air is typically drier then summer air, in that it cannot "hold" as much water vapor. However; during the winter there is a greater temperature difference between the outdoors and indoors. This difference translates into warmer indoor air contacting cold surfaces forming condensation. Mold can now grow on these wet surfaces. The major suspects in forming condensation are windows, doors and exterior walls with windows being the biggest culprit. So, what do you do to help limit the occurrence of mold during the winter? To prevent condensation, one of two things can be done (or both). Raise surface temperatures above the dewpoint (surface temperature at which condensation occurs) and reduce the amount of humidity in the air. Surface temperatures can be controlled through increasing insulation to prevent indoor surfaces from becoming too cold. Humidity can be controlled through dehumidifiers and limiting the addition of water vapor through faulty radiators, cloth driers or excessive showering. At a minimum, the condensation should be wiped up before mold growth can begin, which is usually 48 hours. Greg Krueger is a certified indoor environmentalist and a certified microbial consultant with Lew Corp., Mountainside, N.J.