How fast does mold grow?

Mold requires several conditions to grow. It needs food, moisture, and the right temperature. Once these are met, spores may germinate after 12 hours and can start to grow within 24 to 48 hours. How quickly molds colonize depends on what kind of mold it is, but it can occur after 1 to 12 days. This is why it is essential to act immediately in the event of water damage.