Mould grows from tiny spores that are ubiquitous in the environment. When these spores land on a moist, nutrient-rich surface with suitable temperature and oxygen, they germinate and begin to grow. The process involves spore germination, hyphal growth (branching tubes called hyphae), formation of a mycelium (an interwoven network of hyphae), and eventually the production of new spores that disperse and continue the cycle. Key factors for mould growth include:

• Moisture: Mould needs damp or wet conditions to grow. It thrives in high humidity or areas with water leaks.
• Nutrients: Mould feeds on organic matter such as paper, wood, carpet, fabric, and dust.
• Temperature: Mold generally grows best between 77°F and 86°F (25-30°C), but some species can grow in cooler or warmer conditions.
• Oxygen: Mould requires oxygen to survive but can grow in low oxygen environments.

Mould growth can start within 24 to 48 hours under favorable conditions. It often grows indoors in places like bathrooms, ceilings, carpets, and upholstery where moisture and warmth are present. In summary, mould grows by spores landing on moist, nutrient-rich surfaces, germinating, and developing a network of hyphae that absorb nutrients and expand the colony, eventually releasing more spores to propagate the cycle.