What environmental factor is most critical for mold growth?

Moisture is the most critical environmental factor for mold growth because mold fungi require water to thrive. When organic materials, such as wood or drywall, are exposed to moisture, it creates an optimal environment for mold spores to germinate and proliferate. Even small amounts of moisture can support mold growth, which is why areas prone to high humidity or water damage are particularly susceptible.

While darkness, warmth, and airflow can influence mold growth, they are secondary to the presence of moisture. For instance, mold can grow in relatively low-light conditions, thrive in a wide range of temperatures, and may spread more rapidly in stagnant air. However, without sufficient moisture, mold spores cannot establish themselves and reproduce. Hence, controlling moisture is essential in mold prevention strategies.