How to Kill and Prevent Sidewalk and Patio Moss

When unwelcome moss moves in on walkways, patios and decks, your favorite spots for relaxing and entertaining quickly lose their appeal. Structural moss and algae leave hard surfaces with an unsightly green tinge and turn sidewalks and decks into slick hazards to avoid.
Learn to restore your sidewalks, patios and more by understanding hard-surface mosses and effective moss control:
  1. Understanding Moss on Hard Surfaces
  2. Managing Surface Moss Effectively
  3. Keeping Hard Surfaces Moss Free

High-pressure cleaning can help remove excess moss and prepare sidewalks for treatment.

Understanding Moss on Hard Surfaces

Some mosses thrive in lawns, but other types seek out hard surfaces. These structural mosses flourish on concrete, asphalt, siding and wood – just like mosses that cling to rocks in shady forests. Mosses prefer shady areas with poor air circulation, where surfaces stay damp and sheltered from drying sun and wind. North-facing walls, covered patios and tree-shaded sidewalks provide ideal conditions for surface mosses to grow and spread.

Moss underfoot makes hard surfaces slick and hazardous, but effects extend beyond that. Just as moss can ruin your roof, moss can damage hard surfaces. Once established, mosses hold in moisture that deteriorates surfaces beneath. From concrete and brick to wooden decking, moss shortens the lifespan of walkways, driveways and outdoor areas meant for long-term enjoyment.

Moss can damage wooden decking and create slick, hazardous surfaces.

Managing Surface Moss Effectively

Mosses have a very different structure than other plants in your garden or lawn. Because of these differences, common herbicides and home remedies that kill lawn weeds won't kill moss on sidewalks, decks or patios. In addition, products designed to kill and control lawn moss shouldn't be used on hard surfaces around your home. Many effective lawn moss killers rely on iron-based substances, which naturally create rustlike surface stains. The best products to kill moss on walks and structures kill moss quickly and eliminate stain concerns.

Effective moss control products kill moss by preventing it from holding moisture. Moss can't live without water, so it dries out, turns black and dies. The Lilly Miller Moss Out! line offers highly effective, non-staining controls in easy-to-use liquid and dry formulas:

  • Liquid Lilly Miller Moss Out! Roofs & Walks comes in an economical concentrate, with two sizes for small or large surfaces. It's also available as a convenient, ready-to-spray formula – just attach a regular garden hose and you're ready to go. This product kills moss and algae with the help of ammoniated soap of fatty acids, which work much like insecticidal garden soaps. You'll see the results in just hours.
  • Dry, micro-granule Lilly Miller Moss Out! Roofs and Structures, with two sizes to fit your needs, comes in a ready-to-use shaker container. Based on the active ingredient zinc sulfate monohydrate, this product kills moss without ugly stains. If preferred, mix the granules with water according to label instructions, and apply with a sprinkling can or pump sprayer instead.

Always read product labels thoroughly, follow all instructions, and make sure your label lists the surface material you want to treat. When treating surfaces close to grass and flower beds or foundation plantings, avoid spraying or sprinkling plants. If that happens, rinse the plants off well.

Proactive annual treatments help keep surfaces free from moss.

Keeping Hard Surfaces Moss Free

Moss controls are most effective when applied to during moss's peak growth from fall through early spring. Before treating, remove excess moss with a broom, rake or high-pressure washer to expose underlying moss and improve effectiveness. For best results, treat surfaces just prior to fall or spring rains, when moss is moist and growing, but no rain is forecast for several days. Once mosses turn dark and die, simply sweep dead moss away.

With surfaces free from moss, maintenance is simple. Treat the area each fall or spring to keep new moss from moving in and taking hold. Improving the conditions in moss-affected areas helps reduce future problems. Thinning nearby trees and shrubs allows more light in and exposes moss-prone surfaces to drying sun and wind.

By killing damaging moss on sidewalks, patios and other hard surfaces, you can prolong their usefulness and enhance your family's enjoyment. Lilly Miller Moss Out! moss control products help you protect your property, put an end to slippery surfaces, and safely enjoy your outdoor spaces with friends and family again.

Lilly Miller and Moss Out! are registered trademarks of Central Garden & Pet Company.

Corry's and Moss B Ware are registered trademarks of Matson, LLC.