Are Earthworms a Problem? An Answer to Your Question + How to Fix an Infestation

Earthworms love to live secretly in the soil of our lawn and garden beds and whilst they’re mostly invisible and we’ve all seen them during the wet and humid seasons when they pop up on the surface to say hello!

These little creatures have been known to be beneficial for lawn health due to their burrowing nature, however; alongside these benefits they can be an issue when there is a surplus of them.

Read on to discover the secret power of the earthworm and what to do if they pose a risk to your lawn prosperity.


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What do Worms do for the Earth?

Firstly, let’s talk about what earthworms do for the earth.

When in proper quantities and below surface level, they can be really beneficial to your lawn and soil health – surprisingly!

They are most commonly found in soils rich with nutrients and health so if you see worms in your garden, well done!

They have many benefits, the most common including:

  • Tilling and aerating the soil due to them creating tunnels throughout their travels under your grass.
  • Accelerate decomposition process.
  • Help rotate the soil for increase in organic matter – also due to their movements.
  • Are excellent for monitoring soil health! If you see worms in your garden it can indicate what you need to focus on in terms of lawn care and maintenance.
  • Balance the pH level of your soil (SUPER important for healthy grass).

So, there you go, earthworms can be your best friend when it comes to garden health, however, they also have their downsides too.

red earthworm crawling on green grass

How can Earthworms be a Hindrance in Garden Health?

So, I just told you that they’re great but now they’re not, what do you mean you ask me?

Although they can be great, they can also be troublesome.

As I said above, during the wet and humid seasons they rise to the surface and this is where the issue lies…

When they migrate to the top of your soil, they leave their castings on your lawn. Worm castings are small mounds and bumps left in your lawn that is essentially worm ‘excretion’.

This excretion is packed with nutrients that can help with decomposition and just the overall health of your soil.

So, what’s the issue?

These mounds can be an issue for the gardener that wants perfectly leveled and aesthetically pleasing grass.

The bumps that these castings make give the lawn an uneven texture and on top of this, can leave quarter-sized brown patches scattered across the grass due to their high nitrogen content which can be an over-fertilization problem.

Coupled with the issue of a surplus of worms, these brown spots can be a major downer when you’re trying to keep your grass looking perfect!

In the case of a weak or thin lawn, when mowed these undesirable brown patches become more obvious, as does the unevenness of the grass surface, both a no-no when you want pristine lawn.

Second, to this casting problem is the issue of animal pest attraction.

Nocturnal animals are notorious for ravaging through gardens looking for food. For moles, skunks, and raccoons these worms can be a food source, therefore, will dig up your grass to find them.

earthworm crawling on green lawn

How to Get Rid of Earthworms in Lawn

Worms, when in copious amounts, can be an indication of improper lawn maintenance and show signs that your garden needs raking, thatching, and fertilizing.

When in the dryer seasons and the worms are below the level of your lawn, they are low risk and can potentially be beneficial, it is only when they rise to the surface that your grass will need a little extra TLC due to their castings.

There are no commercial-grade pest killers that target earthworms, but many pesticides are toxic to them so will do the job in killing them, however, using pesticides isn’t preferable as it can kill ALL of them and that will also be bad for your lawn health as worms are actually an important member of the ecosystem.

If you believe you have an excess worm issue, there are many natural methods that you can implement to make their living environment inhospitable.

earthworms group in gardeners hand

Method 1: Removing Food Source

Remove the thatch from your garden.

Thatch is any dead grass or debris that creates a layer underneath your grass and it the food for earthworms and other ground-dwelling creatures.

To remove the thatch, apply a thatching blade to your lawnmower and mow in a single direction, such as east-to-west, which will pull up the unwanted debris.

After you have done this, scoop it up and add to a compost heap. Once this has been fully composted, it can be added back to your lawn as an extra organic material source that will promote healthy grass.

If you believe your lawn needs extra thatching, run the mower with the thatching blade in a north-to-south direction. Once the thatching is properly done, you will notice that there will be exposed soil just peeping through below your grass.

Thatching is also great for creating an even color in your grass as it removes the dull and dead grass which increases the healthy green color and the vibrancy of your lawn, giving the impression of a well-kept and lush turf!

This YouTube video is a great demonstration in showing the proper way to thatch grass to get the most optimal results!

Method 2: Change the pH Level of Your Lawn

Worms can’t survive in an environment that is too acidic, therefore, if you lower your soil’s pH using ammonium sulfate to around 4.5 they will find it difficult to live.

After doing this, you’ll need to water the lawn to distribute it lower into the soil.

Method 3: Lawn Maintenance

Regular lawn maintenance is important for making an earthworm’s environment difficult to live in.

Proper mowing techniques and lawn care is essential, so you need to ensure that you keep on top of your raking, aeration, and watering.

Fertilizing is also great for getting rid of earthworms as the increased nitrogen contact will ward them off. However, it is better to apply the fertilizer in the fall before the worms start to rise to the surface and to risk burning your lawn in summer.

There are many lawn-care mistakes that actually PROMOTE the existence of worms in your garden, therefore, you need to be aware of the health of your lawn and what it needs so that you can prevent a worm infestation.

Grass thickness is also important in a worm’s environment as they love to live in loose soil due to the fact that they breathe through their skin – crazy right?!

Improving the density of your grass and soil will also prove to be an effective way to reduce the worm population in your garden, to learn how to make your grass fuller and thicker read this article!

beautiful house with green grass front-yard lawn

Method 4: The Casting Issue

The casting mounds are an issue for gardeners who want to achieve a beautiful lawn, but they aren’t that bad when under control!

As the castings are full of nutrients and are great for the health of your grass and plants, they can be useful to you. Simply rake the mounds evenly across your grass, making sure you don’t leave any clumps that can cause over-fertilization. Once having done this, water the lawn to soak in the castings.

Other than this, you can also scoop the castings up and place them in a compost heap – if you have one – as this will promote the decomposition of the organic waste and create a nutrient rich compost that will be great for your garden later on!


Earthworms are weird, yes but they can be great and help to balance nitrogen fixation and promote soil conditioning.

But I get it, they can also be an issue and this issue sometimes needs to be fixed, so I hope that this blog will help you in your worm-fighting adventures!

What do you think, are there any other methods that can be used to get rid of earthworms?

Let me know in the comment section if you or anyone else has experienced an earthworm issue and how you overcame it.

Andy Gibson

My name's Gibson. Andy Gibson. I like to think of myself as the Bond of the backyard, that is if yard work ever became sexy. I write about everything about indoor and outdoor gardening and the dread-it-but-still-need-to-do-it chores around the yard, like cleaning out the gutter guards.

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