How Dish Soap Can Kill Unwanted Moss in Your Lawn

dish soap to kill moss illustration

The Spruce / Nusha Ashjaee

Moss is not always considered a weed, but don't tell that to those who have tried to deal with it. Here's a recipe for getting rid of moss in a lawn with dish soap. It's safer than chemical pesticides and only a fraction of the cost. It sounds odd but it works and is used by turf professionals everywhere.

All About Moss

Moss is a thick mat of tiny green leaves and threadlike stems growing on your lawn, bare soil, wood, rocks or any other surface where moist, shady conditions are present. Moss has very shallow roots and gets most of its food from the water washing over it. It is a primitive plant that reproduces by spores.

During the Cambrian period, about 540 million years ago, some early plants evolved from earlier algae that could live on land, outside of the water. These plants were like modern moss. All of the animals were still living in the water, so on land, there was only moss and mushrooms.

Eradicating Moss

Moss does not kill grass, but it is an indicator of poor conditions that need to be addressed for a lawn to be healthy and moss-free.

Moss does not grow well when there are high levels of iron in the soil. To get rid of the moss you can spread lawn moss killer, which usually contains some form of iron sulphate (ferrous sulphate or ferrous ammonium sulphate). You can add lime to the soil with a spreader to make the soil less acidic, which favors grass and is less favorable to moss. You can also rake out the moss and physically remove it from the lawn. Or, the moss can be eradicated using a simple solution of water and dish soap.

The problem is that none of these options work long term. Unless you fix the real underlying problems that are preventing the grass from growing well, the moss will soon return to the lawn.

Dish Soap as an Effective Moss Killer

Mix 2 ounces of dish soap into 1 gallon of water in a garden hand sprayer. Most growers prefer Ultra Dawn liquid dish soap. Spray the mixture on the patches of moss. Holding the spray nozzle a couple of inches from the target, drench the moss with the solution. The patches of moss will turn orange/brown in 24 hours and eventually dry-up while the surrounding grass takes over.

To treat large areas, spray the mixture with a garden sprayer until there is a runoff. Use 4 ounces of dish soap per 2 gallons of water for every 1,000 square feet of lawn. Apply when the grass is moist and it is not going to rain within 24 hours of application.

Rake up the dead moss once it turns orange/brown. If more moss appears, repeat the treatment until it temporarily stops returning.