Moss growth and other plant organisms are a common problem on stone, concrete, and other surfaces that remain shaded and fairly moist throughout the day. It is important to remove moss, especially over walking paths, as it can be quite slippery and poses a hazard. Below are a series of methods for moss removal from concrete.
Step 1 – Boiling Water
It is recommended to aim for something simple before using chemicals of any kind to clean moss off pavement. Try using boiling water, especially in areas near grass or other wanted plant growth. Carefully pour the boiling water over the moss, scrub with a stiff brush, and use a hose to wash away any debris.
Step 2 – Power Sprayer
The power sprayer, like boiling water, is another environmentally safe way to combat moss growing on concrete. If one isn’t available, you can always rent one. However, you can only wash small areas at a time, so washing a large stretch (such as your driveway) will not only take some time but will take a good deal of water and may not be entirely successful at getting rid of all the moss.
Step 3 – Ammonium Sulfamate
Ammonium sulfamate can be found in most garden supply stores, and it is a water-soluble solid so you will need a garden sprayer or watering can to apply it. Avoid areas with other desirable plant life, and be sure to follow all of the manufacturer’s instructions. As with any chemical product, but especially ammonium sulfamate, be sure to use your protective gear, as it can cause irritation to the skin, eyes, and lungs. It is best used on a day with no wind, to keep it from blowing onto other plants and further prevent direct contact.
Step 4 – Sodium Pentachlorophenate
Sodium pentachlorophenate can also be used, though you should be aware that it is a known carcinogen. Apply using a solution of 1 part sodium pentachlorophenate to 8 parts water and thoroughly cover the moss covered areas. Apply it again if it rains within 24 hours.
Again, safety is important, so please use protective gear when handling this chemical as well. The moss should die off within a week. Brush away excess with a broom. It should also prevent moss from growing back for at least several weeks.
Step 5 – Bleach
Household bleach can be used as well, though garden supply stores often sell bleach specifically for killing moss. Mix a solution of half bleach and half water. Use a sprayer to cover the area, scrub it, then use a hose to rinse it off. Be sure to follow all directions on the container and use your protective gear. This method should keep the moss from growing back for as long as a year.
Step 6 – Baking Soda
Baking soda will also often do the trick. Sprinkle it over the moss covered areas and let it sit for at least 24 hours. Carefully sweep it up and dispose of the powder.
Be sure whenever possible to start with environmentally friendly means of moss removal before immediately resorting to chemical solutions that could potentially be dangerous. If you do use chemicals, always wear some sort of protective gear and be extremely careful.