10 Best Moss Killer For Roofs 2025 in the United States

The 30 Seconds Outdoor Cleaner is designed to tackle moss, algae, mold, and mildew stains on a variety of outdoor surfaces including wood decks, concrete sidewalks, vinyl siding, and more. It comes with three 64-ounce bottles and a hose-end spray attachment, making it straightforward to use. Simply attach the sprayer to the bottle, spray the solution on the stained surface, and rinse off with water – no pressure washing is required.

This product covers up to 900 square feet, which is a decent range for most home cleaning tasks. One of its key strengths is its safety; when used as directed, it won't harm your lawn, trees, or other plants, making it environmentally friendly. However, it's important to follow safety precautions as with any chemical cleaner.

This cleaner is particularly suited for homeowners looking for a quick and easy solution to clean outdoor moss and algae stains without the need for harsh pressure washing.

The Wet & Forget Moss, Mold, Mildew, & Algae Stain Remover is a versatile outdoor cleaner designed to tackle a variety of surfaces including roofs, wood, decks, concrete, and siding. This product shines in its simplicity of use; you just mix it with water, spray it on, and then let the weather do the work—no scrubbing or rinsing required. It's quite effective on green stains, which typically clear up in 1-2 weeks, while more stubborn black stains may take several months to disappear.

A major benefit is that the surfaces can remain clean for up to a year or longer after treatment, providing long-lasting results. Another advantage is that it’s fragrance-free and unscented, which is great for those sensitive to strong chemicals. The product comes in a generous 128 fluid ounce size, allowing you to cover a large area, and it has an indefinite shelf life once mixed, which adds to its convenience.

On the downside, the product requires a bit of patience as it relies on natural weather conditions such as wind and rain to clean the surfaces, meaning immediate results are not to be expected. Additionally, it’s essential to apply the product on a day when rain is not forecasted within 4-5 hours to ensure its effectiveness. In terms of safety precautions, you should use it carefully to avoid any unintended environmental impact and ensure you are working in temperatures above 32°F. It’s a solid choice for anyone looking for an easy, long-lasting solution to outdoor stains without the hassle of extensive labor.

Wet & Forget Outdoor Moss, Mold, Mildew, & Algae Stain Remover is a solid choice for homeowners dealing with unsightly moss and algae on roofs and other outdoor surfaces. Its standout feature is the Xtreme Reach Hose End nozzle, which can spray up to 30 feet, making it easy to target hard-to-reach areas without much hassle. This product is designed to be safe and user-friendly, as it is bleach-free and non-acidic, reducing the risk of harming nearby plants or water sources when used correctly.

One of the strengths of this moss killer is its long-lasting effectiveness. Once applied, the cleaner works with rain and wind to gradually eliminate stains over time. Users can expect to see results on green stains within a couple of weeks, while tougher black stains may take longer to disappear—sometimes up to six months. This slow-acting nature can be a benefit for those who prefer a no-fuss solution, as there’s no need to rinse the product away after application. However, the product requires specific weather conditions for optimal application—ideally on dry, cool days with no rain forecasted for several hours. Additionally, while it can cover a substantial area of up to 2,000 square feet, heavily stained or porous surfaces may absorb more product, potentially leading to needing more than one bottle for complete treatment.