How do I remove moss from my rooftop, lawn, and driveway without using chemicals?
In our Summer 2001 issue, we recommended sweeping your sidewalk, driveway, and roof regularly with a stiff broom to prevent moss growth. But to remove the moss that’s already there, a trusty colleague reports success with applying wood ash, which kills the acid-loving moss by making the pH more alkaline. Then your moss will wash away. But, if applying wood ash to kill rooftop moss, make sure the residue in the downwash won’t kill any acidic plants in your yard. If you have garden lime on hand, which is often used to reduce acidity in soil, applying this on your unwanted moss will have the same effect.
Moss does no harm to your garden or lawn, but it can wear down your rooftop. Thick moss growth retains moisture on roofing materials, advancing wood rot and eroding asphalt in shingles.
Killing or removing moss will not prevent regrowth unless the conditions that foster its growth are changed. Improve water drainage, increase direct sunlight, or add competitive plants such as grasses.