Moss and algae growths are common problems in concrete, stone, and other surfaces outside your home. These pesky plants usually thrive in places that remain shaded and moist throughout the entire day. Removing them is important – especially over walkways – as these plants can be quite slippery and hazardous. Listed below are tried and tested methods for moss and algae removal from concrete.
Method #1: Shovel and Knife
If the moss growth has gotten too thick, you can use a shovel to scrape off most of it. Take note that this method entails scraping metal against concrete—it’s going to be loud. So as not to disturb your neighbors, it’s best to do this during the day. Use a knife to easily remove the thinner and tougher stuff.
Method #2: Ammonium Sulfamate
Most garden supply stores sell ammonium sulfamate. It is a water-soluble solid so a watering can or garden sprayer is needed to apply it. For safety’s sake, keep away from areas with plant life and always read the manufacturer’s instructions. When using any chemicals, don’t forget to wear protective gear.
Method #3: Pressure Washer
Similar to boiling water, using a pressure washer is an environmentally safe and chemical-free way to stop moss from growing on your stone walkway. If you don’t have one, you can always rent one from gardening shops. The only drawback with this method is that you’re limited to washing a small portion at a time. This means washing a large area (i.e. driveway) will take a lot of time and a good amount of water.
Method #4: Bleach
Household bleach is a common chemical that kills moss. Simply mix a solution of half bleach and half water. Spray the mixture on the area and scrub it thoroughly before using a hose to rinse everything off. Remember to follow the instructions in the container and, again, wear protective gear.
Method #5: Baking Soda
If you hate chemicals, baking soda will do the trick. Sprinkle the powder over the moss-covered areas and let it stay there for a day. Ideally, the moss should crumble and disintegrate under the powder. Sweep up the mess after 24 hours and carefully dispose of the powder.
Method #6: Boiling Water
Another chemical-free method is to use boiling water. Slowly and cautiously pour the boiling water over the moss before using a stiff brush to scrub the surface. You can then wash away any debris using regular water from a garden hose.
Method #7: Sodium Pentachlorophenate
Sodium pentachlorophenate is another known anti-moss chemical. However, you should also be aware that it’s a known carcinogen. Safety should be your priority, so use all chemicals indicated in this list with extreme caution. With this method, moss is expected to be gone in a week. Brush off any debris with a broom. This chemical should prevent moss from growing again for at least several weeks.
Once you’ve gotten rid of moss from surfaces, maintenance is easy. Treat areas each spring or fall to prevent new moss from growing and taking hold. By immediately killing damaging algae and moss from patios, walkways, and other hard surfaces, you can keep your garden safe and beautiful for a long time.