Why does stucco turn green, gray and black in Bonita Springs?
Warm temperatures and high humidity keep walls damp for much of the year. After a summer afternoon storm, the north and shaded sides of a house stay wet long after the sun returns. That is where algae takes hold first.
- Green growth shows up low on walls, behind shrubs and under roof overhangs.
- Black or dark gray streaks are mildew and fungi, often settled into the texture of the stucco.
- Orange rust spots often trace back to irrigation spray that hits the wall. Iron in some well water leaves those marks, and a rust remover is needed on top of the wash.
- Chalky film is old paint breaking down in strong sun.
Homes closer to the coast also collect a gray salt and dust film. Regular cleaning is easier than waiting until the growth is thick.

