How to kill moss in lawn

Moss in the lawn is an unmistakable sign that something is wrong with your grass. In this article, we explain the different reasons why moss grows on your lawn and we also list the different solutions you can put in place to control it. At the end of this article you will have a complete overview of the different root causes as well as a various number of solutions to have a green and healthy lawn.

What is moss?

Moss are plants called bryophytes that are characterized by having neither conductive vessels, nor flowers, nor fruits, not even real roots. They were one of the first plants that colonized the humid regions of the Earth, about 350 million years ago.

Its height does not exceed 10 cm. However, it can cover a large area, such as a rock or even a wall (after some time). It grows in any humid place protected from direct sun. During the dry season moss withers almost completely, but once the rains return it turns green again.

Although moss may seem delicate and fragile, the truth is that mosses are quite strong and resistant. Various species can be found from the shores of the Arctic Ocean to some places in Antarctica, passing through the tropics. Some manage to survive in deserts, while others live submerged in swamps and streams. In general, most mosses prefer humid, shady sites. In the forests they usually form thick blankets that completely cover the rotten logs and the ground.

Is moss bad for your lawn?

Moss does not kill the grass. It simply thrives on growing conditions that are unfavorable for grass, such as deep shade, poor drainage, poor fertility, or compacted soil. These conditions (not the moss) ultimately cause the grass to die out.

What causes moss in lawns?

Shade

As mentioned, moss loves shade, especially the one caused by trees. Therefore, if you are struggling with moss growing in your lawn, you should pay attention to what is causing the shade in your garden.

Poor drainage

It creates an environment conducive to the appearance of moss. Poor drainage prevents grass from healthy growth. Moss can grow in the patchy areas where the grass is not strong enough.

Acid PH

Having a ph of less than 5 means that the soil is acidic which creates a great environment for moss to grow. While this is great for moss development, acidic soils do not provide enough nutrients for a healthy grass. That is why controlling the acidity is essential to have a nice and vivid green lawn as well as to control the presence of moss in your garden.

Insufficient fertilization 

A lawn with nutritional deficiencies is invaded by moss more easily than if a rational fertilization plan has been carried out. Always remember that not giving enough nutrients to your grass will affect its growth which gives moss space to invade your lawn.

Presence of bald spots on the lawn

In those areas where the grass has disappeared for different reasons (trampling, diseases, waterlogging, etc.), the moss takes control of the surface much more easily. Cutting the grass at a very low mowing height is another factor that can facilitate the presence of moss.

Lawn maintenance services 

How to get rid of moss?

There are different solutions you can put in place to get rid of the moss that is invading your lawn. There are many chemical herbicides available in the market, organic solutions as well as DIY options that will help you to get rid of the moss that is affecting your lawn.

Chemical method

The first thing you should do to remove the moss in your lawn is actually kill it. You will find different chemical herbicides that will help you with this task. Most weed killers are iron-based herbicides that will not only target the moss but also feed your lawn at the same time. It is very important that you find a product that works specifically for moss, as there are also options for other weeds that may not work on moss and can damage your grass.

Is there an ideal time to apply this herbicide? Spring and early fall (when moss is in its peak growing season) is when these products are more effective. But no worries if you are reading this too late as these treatments are effective at any time of the year.

Organic method

If you would like to avoid introducing herbicides into your garden, there are also organic alternatives that use bacteria instead of ferrous sulfate to break down the moss. These moss control products have an advantage compared to chemical killers: the bacteria “eats” the moss, so you will not see the moss turning black and it needs not raking out.

If you decide to use an organic moss killer, we suggest that you use it when the temperature is above 15ºC to be effective. 

DIY method: killing moss with vinegar

For those that would like to spend some time and do a  lawn moss killer homemade, we have a DIY herbicide you can make with just three ingredients. All you have to do is mix together:

• 4 cups of vinegar

• ¼ cup of salt

• 2 teaspoons of dish soap 


If the affected area is larger than what you can cover with this amount of solution, you can make as much as you want, just maintain the same proportions of ingredients. To apply it, use a garden sprayer and try to saturate the patches of moss to obtain the best results. You don’t need to worry about how it can affect your grass as this solution will not have any impact nor damage your grass.

After 24 hours, the moss will turn orange/brown and die. This is the right time to remove it with a metal rake. Make sure you remove the whole moss plant and put it in a sealed bag away from your lawn.

Gardening tips for beginners 

How do you prevent moss from returning?

When we talk about controlling moss, we need to think about getting rid of it but more important is to take the necessary actions to prevent it from coming back. As we said before, moss does not kill your grass, but having moss in your lawn means that your grass does not have the proper conditions for a healthy growth. 

To prevent moss from returning to your lawn, you need to improve the conditions for the grass to grow and make it inhospitable to the moss.

Check the cutting height of your mower

Check the cutting height of your mower. Never cut the scalp of a lawn that is too short. This will weaken the lawn and leave the soil open to moss invasion. When moss is a problem, leave the grass so that it is at least 2.5 cm (1 inch) long. Mow regularly (at least once a week) to encourage the spread of the grass. In autumn and winter leave the grass even longer.

Improve drainage

Moss likes a moist environment, but also if poor drainage is affecting your grass’s health, moss will take advantage of the patchy areas to conquer them. To get rid of moss for good you will need to improve your lawn’s drainage.

What causes poor drainage? First, the type of soil you use in your lawn may not be adequate to facilitate drainage. Make sure you are using a sandier soil (instead of a clayey one), but if you live in a region where soil is clayey, you can help drainage by aerating and adding some compost. Heavy foot traffic also contributes to poor drainage. For example, children playing regularly in your lawn or if you normally host garden parties, then you must be quite sure that your soil is compacted and not draining correctly. 

Here is an easy way to check if your soil is compacted: 

• Try to stick a shovel into your turf. Depending on how easily the shovel sinks, you will see if the soil is compacted or not. If the soil drains correctly, the shovel will easily sink up to 8 inches into the ground. If it does not, it’s time to think about aerating your soil to improve drainage. We recommend a yearly aeration that will improve the conditions for your grass to grow. You can get your price here!


Another important point to take into account when talking about drainage is to make sure your lawn does not collect standing water when raining. If that happens you should take actions to improve your lawn’s drainage system. As a first step, you should find the depression spots where water stands and fill them with dirt and soil to level the ground. If this is not possible, then you should think about installing a more complex drainage system with the help of an expert.

Maybe too much shade?

Moss loves shady spots, so in order to control moss advancement in your lawn you should try to reduce what is causing that shade. Make sure you prune your trees regularly and remove objects that may be blocking direct sunlight to your lawn. If you don’t want to give up shade, then you should think about alternatives other than grass for the shady areas: it could be another kind of ground cover made of shade-loving weeds. 

How do you grow grass under a tree? 

Lawn maintenance services

If you need professional help to get rid of that moss in your lawn, Vertdure is here to help you!  We are the leaders in green space treatment and our network covers all of Quebec. Do not hesitate to contact us if you have an issue with moss in your lawn. You can check all of the services we offer by clicking here.