What this video covers
The clip lays out the growth timeline hour by hour.
Within about 24 hours settled spores begin germinating on a damp surface. From there the progression to established growth is measured in days, not weeks, which is why response time dominates outcomes.
The takeaway
The window for drying something out rather than removing it is short. Treat any wetting event as needing action the same day.
Read the full written guide: How Long Does Black Mold Take to Grow?.