Why does siding get moldy?

Siding materials like wood and vinyl can get moldy over time. Mold usually comes from excessive moisture, lack of sun, or dirt buildup on your siding. There are ways to prevent mold, like removing plants close to your home and fixing any rain gutters, but there are also cleaning solutions to remove mold after it appears on vinyl siding. Wood siding will most likely have to be replaced if there is mold on it.