Every spring, those telltale coiled mounds appear overnight, signaling the arrival of earthworms in your lawn. If you are searching for how to get rid of dew worms, you likely want a smoother, safer surface for walking and playing.
These mounds, also called worm casts, are not harmful to the grass itself. However, they create a messy, uneven lawn and can become slippery when wet.
You have a few solid options. Some methods are quick fixes, while others are long-term lawn care strategies.
Let’s break down the most effective ways to manage these wiggly visitors.
Understanding The Dew Worm Problem
Dew worms are large earthworms that come to the surface at night. They pull organic matter down into their burrows and leave the digested soil behind.
This activity is actually great for soil aeration. But for a pristine lawn, it is a headache.
You might see small, lumpy hills all over the grass. These are the casts that dry and harden, making mowing difficult.
Why They Appear In Your Lawn
Dew worms love moist, cool conditions. They thrive in soil that is rich in organic matter, like thatch or compost.
If you overwater your lawn, you are inviting them to the surface. They need the moisture to move around and breathe.
Heavy clay soils also hold water, which attracts them. Lawns with a thick layer of thatch provide a perfect food source.
Are They Actually Bad For Grass?
No, the worms are not eating the grass roots. They are eating dead leaves and other debris.
The casts they leave are actually full of nutrients. The problem is purely aesthetic and physical.
Those mounds can smother the grass if they are thick enough. They also create a bumpy surface that is unpleasant to walk on barefoot.
How To Get Rid Of Dew Worms
This is the core question, and there is no single magic bullet. You need a combination of habitat modification and direct control.
Chemical options exist, but they are often harsh. Many homeowners prefer natural methods first.
Here is a step-by-step plan to reduce their numbers and their mess.
Step 1: Reduce Soil Moisture
Dew worms need wet soil to survive. If you dry out the top few inches, they will move deeper or die.
- Water deeply but less frequently. Instead of a light sprinkle every day, water once or twice a week.
- Improve drainage. Aerate the lawn to break up compacted soil.
- Water in the early morning. This allows the grass to dry before nightfall, when worms come out.
This is the most important step. It changes the environment so it is less hospitable.
You will notice fewer casts within a few weeks of adjusting your watering schedule.
Step 2: Manage Thatch And Organic Debris
Worms feed on thatch and dead grass clippings. If you remove their food source, they will look elsewhere.
- Dethatch your lawn in the spring or fall. Use a power rake or a manual dethatching rake.
- Mow regularly and bag the clippings. Do not leave thick piles of cut grass on the surface.
- Rake up fallen leaves in the autumn. Do not leave them to decompose on the lawn.
This makes the lawn cleaner and less attractive to worms.
It also improves air circulation, which helps dry the soil faster.
Step 3: Adjust Your Soil PH
Dew worms prefer neutral to slightly acidic soil. They do not like highly acidic conditions.
Applying a soil acidifier can help deter them. Sulfur or ammonium sulfate are common options.
Test your soil first. You want a pH between 5.5 and 6.0 for worm deterrence.
Be careful not to make it too acidic, as that will harm the grass. This is a balancing act.
Step 4: Use A Chemical Drench (Last Resort)
There are chemical products labeled for earthworm control. They usually contain carbaryl or imidacloprid.
These are effective but can harm beneficial insects in the soil. Use them only if natural methods fail.
Apply the drench in the evening when worms are near the surface. Water it in thoroughly.
You will see worms come to the surface shortly after. Rake them up and dispose of them.
Note that this is a temporary fix. New worms will move in if the habitat remains ideal.
Natural Repellents And Home Remedies
Many people ask about natural ways to repel worms. Some have anecdotal success, but results vary.
These methods are safer for pets and children. They are worth trying before reaching for chemicals.
Using Mustard Water
This is a classic trick. Mix a few tablespoons of yellow mustard powder with a gallon of water.
Pour it over a small area of the lawn. The mustard irritates the worms, forcing them to the surface.
This does not kill them. It just brings them up so you can pick them up and relocate them.
It is a good way to reduce the population in a specific spot, like a doorway.
Tea Tree Oil Or Garlic Spray
Some gardeners swear by strong-smelling sprays. The idea is that the scent deters worms from coming up.
Mix a few drops of tea tree oil with water in a spray bottle. Spray the lawn surface in the evening.
Garlic juice mixed with water can also work. Reapply after rain or heavy dew.
These are not guaranteed solutions. But they are harmless and smell better than chemicals.
Sand Or Diatomaceous Earth
Diatomaceous earth is a sharp powder that cuts the worms’ skin. It is abrasive and dehydrating.
Spread a thin layer over the lawn. It works best when dry.
However, it can also harm beneficial insects like beetles. Use it sparingly.
Sand can be top-dressed onto the lawn to improve drainage. This helps dry the soil, which deters worms.
Physical Removal And Prevention
Sometimes, the simplest method is the best. You can physically remove the worms when they are active.
This is time-consuming, but it works for small lawns or specific problem areas.
Nighttime Picking
Go out with a flashlight a few hours after sunset. The worms will be lying on the surface.
Pick them up with gloves and place them in a bucket. Relocate them to a compost bin or a wooded area.
Do this after a rain shower when they are most active. You can remove dozens in one session.
This is a great way to lower the population without any chemicals.
Rolling The Lawn
You can use a lawn roller to flatten the mounds. This does not kill the worms, but it smooths the surface.
Roll the lawn when it is slightly damp, not soaking wet. This presses the casts down.
It is a cosmetic fix. You will need to repeat it after each worm activity period.
It makes the lawn safer for walking and mowing immediately.
Long-Term Lawn Care Strategies
Prevention is always better than a cure. By changing how you care for your lawn, you can reduce worm activity.
This takes time, but it creates a healthier lawn overall.
Fertilize With Nitrogen
Worms prefer soil low in nitrogen. High nitrogen levels can deter them.
Use a nitrogen-rich fertilizer in the growing season. This promotes green growth and discourages worms.
Be careful not to burn the grass. Follow the application rates on the package.
This is a natural way to make the soil less appealing to them.
Mow Higher
Keep your grass a bit taller. Taller grass shades the soil, keeping it cooler and moister.
Wait, that actually attracts worms. So, mow lower to let the soil dry out faster.
However, do not scalp the lawn. Keep it at a moderate height to avoid stress.
Balance is key. You want the soil surface to dry quickly after watering.
Consider A Worm-Free Grass Type
Some grass types are more tolerant of dry soil. If you have a fescue lawn, it may do better.
Tall fescue has deep roots and can handle drier conditions. This makes the environment less worm-friendly.
If you are renovating your lawn, consider this option.
Frequently Asked Questions
Here are some common questions about dealing with dew worms. These answers should help clarify a few things.
Will Lime Get Rid Of Dew Worms?
No, lime actually makes the soil more alkaline. Worms prefer neutral to alkaline soil, so lime can attract them.
You should use sulfur or ammonium sulfate to lower the pH instead.
Are Dew Worms The Same As Nightcrawlers?
Yes, they are often the same species. Dew worms are the large worms that come out at night.
They are also called nightcrawlers or angleworms. The name “dew worm” refers to their activity after the dew settles.
Do Dew Worms Damage The Lawn Roots?
No, they do not eat living grass roots. They eat dead organic matter in the soil.
Their burrowing can actually help aerate the soil. The damage is only to the surface appearance.
How Long Does It Take To See Results?
If you change your watering habits, you may see fewer casts in 2-3 weeks. Chemical treatments work faster, usually within a day.
Natural methods take patience. It is a process of making the habitat less inviting.
Is It Safe To Use Pesticides For Worms?
Most lawn pesticides are not specifically labeled for earthworms. Using them can harm beneficial soil life.
It is better to focus on cultural controls. Only use chemicals as a last resort for severe infestations.
Always read the label to ensure it is safe for your grass type and pets.
Dealing with dew worms is about managing the environment. You will not eliminate them entirely, but you can keep their numbers low.
Focus on drying the soil and removing their food. That is the most effective long-term strategy.
You can have a smooth lawn again. It just takes a little effort and consistency.
Start with the watering schedule. That is the easiest change to make.
Then, look at the thatch level. Remove any buildup you find.
If you stay consistent, the mounds will become less frequent. Your lawn will look cleaner and feel safer.
Good luck with your lawn. You will see improvement soon.