10 Best Moss And Algae Killers 2026 in the United States

The '30 Seconds Outdoor Cleaner' is designed to quickly and effectively remove stains caused by algae, mold, mildew, and moss on various outdoor surfaces like wood decks, concrete, asphalt, brick, plastic, and vinyl siding. One of its notable strengths is its safety for lawns and plants, making it a good choice for environmentally conscious users.

The application method is straightforward: you attach the hose end sprayer to the bottle, spray the surface, and then rinse off, eliminating the need for pressure washing, which enhances ease of use. Each pack includes three bottles, each with a capacity of 64 fluid ounces, collectively covering up to 900 square feet, which is quite generous.

The product is versatile and works on multiple surfaces, which is a significant advantage for homeowners looking to clean various outdoor areas without needing multiple specialized cleaners. However, it is essential to follow the instructions carefully to ensure safety and effectiveness. A potential drawback is the product's need for proper handling to avoid any misuse, and although it is safe for plants and lawns, users should still be cautious around delicate flowers and shrubs. Additionally, while it offers a quick cleaning solution, very stubborn stains may require multiple applications or some scrubbing. The cleaner's weight and dimensions make it manageable for most users to handle and store. In summary, the '30 Seconds Outdoor Cleaner' is an effective and user-friendly solution for tackling moss and algae stains, especially suitable for those who prefer a simple application process and eco-friendly options.

Wet & Forget Outdoor Stain Remover is designed to clean moss, algae, and other outdoor stains from multiple surfaces like roofs, siding, driveways, and decks. Its standout feature is the hose-end applicator with a new nozzle that sprays up to 30 feet, making it easier to reach high or large areas without much effort. You simply attach it to your garden hose and spray on a dry, cool day. No rinsing is needed afterward, which saves time and fuss. One bottle covers up to 2,000 square feet, but heavily stained or porous surfaces might need more product.

This cleaner doesn’t use bleach or harsh acids, which means it’s safer for your plants and the environment if you follow precautions like avoiding spraying near water bodies and rinsing plants before and after. The cleaning works gradually with wind and rain, with green stains fading within 1-2 weeks, while stubborn black stains or heavy buildup can take months—even up to a year—to disappear fully. This slow action means it’s not the best choice if you want instant results but can keep surfaces clean for a long period once done.

Ease of use is a strong point: no mixing or scrubbing is needed, and the hose attachment helps cover large areas quickly. However, you do need to wait for suitable weather conditions and avoid applying when rain is expected soon. Some users might find the long wait time for deep stains a drawback. Wet & Forget is best suited for homeowners looking for a low-effort, environmentally friendlier solution to maintain outdoor surfaces over time rather than a fast-acting cleaner.

Lilly Miller Moss Out Concentrate is a liquid solution designed to kill moss and prevent its regrowth, particularly on lawns. Its active ingredient, ferric sulfate at 35%, works quickly to eliminate moss without harming grass, making it ideal for maintaining healthy lawns. Each gallon covers up to 2,000 square feet, making it suitable for medium to large lawn areas. Application is straightforward since it is a liquid concentrate, but proper dilution according to instructions is required.

Users often appreciate how fast the product works, typically seeing results shortly after application. While ferric sulfate is effective, it is important to handle the concentrate carefully and follow safety guidelines to avoid environmental impact or harm to pets and children. The product is well-regarded among moss control options and is not discontinued.

Because it is a chemical treatment, those seeking organic or less harsh alternatives might consider other products. Additionally, the 22-pound container might be somewhat heavy for some users to handle easily. Lilly Miller Moss Out Concentrate represents a reliable and efficient moss killer for lawns, especially for those who want quick results and are willing to follow safety directions carefully.