Why Moss Grows on Pavers and How to Stop It

Moss on a two-year-old paver walkway isn't a mystery—it's a moisture problem. Moss thrives where surface water lingers: shaded north sides, areas under tree canopy, or zones hit daily by irrigation overspray. The pavers themselves aren't the cause; the environment is.

Fix the Moisture, Fix the Moss

• Adjust irrigation: Redirect heads, reduce run times, or cap zones that overspray the walk.
• Improve drainage: Ensure the base (¾-inch crushed stone, 4–6 inches deep) and bedding sand (1 inch) are intact and the walk slopes ¼ inch per foot away from structures.
• Increase sun/airflow: Thin overhanging branches; remove dense groundcovers trapping moisture at edges.

Chemical Control (If Needed)

For existing moss, apply a potassium salts of fatty acids product (e.g., Scotts MossEX, Lilly Miller Moss Out) or a zinc-based moss killer. Follow label rates. These are contact killers—moss turns brown in days. Sweep or pressure-wash off debris after it dies.

Prevent Regrowth

Once clean, apply a penetrating silane/siloxane sealer to the pavers and joint sand. It reduces water absorption, slowing moss return. Reapply every 3–5 years. Polymeric sand in joints also resists weed and moss establishment better than plain sand.

Moss is a symptom, not a disease. Dry the walk, and the moss won't come back.