Does Hydrogen Peroxide Kill Worms in Soil?

Hydrogen peroxide has become a cure-all in gardening, and for a good reason. Hydrogen peroxide is water with one additional oxygen molecule (H₂O₂), and it works by releasing oxygen when it gets warm or is in sunlight. This reaction can work wonders for killing fungi, worms, and some insects.

Hydrogen peroxide kills worms in soil but is not always immediately effective. Variables such as the bacteria in your soil, the worms’ size and resistance to peroxide, and the duration of treatment can alter the efficacy of hydrogen peroxide for killing worms and other pests.

When it comes to killing worms in your soil with hydrogen peroxide, there’s more at play than meets the eye. So, let’s get down to the facts and discuss how effective hydrogen peroxide is at killing worms and other soil-borne pests. I’ll also tell you the best way to kill worms with this household cleaner and discuss the pros and cons.

How Does Hydrogen Peroxide Kill Worms and Pests?

Hydrogen peroxide kills worms and pests by damaging an organism’s cell structures. After you expose the peroxide to light or heat, it will degrade and re-bond with the atoms in an organism’s cells and tissues, causing damage.

Hydrogen peroxide’s chemical composition is what makes it helpful for eliminating fungi, bacteria, and worms.

It consists of two hydrogen atoms and two oxygen atoms. The oxygen atoms are bonded together, but this connection is volatile. As soon as you expose the peroxide to light or high temperatures, the oxygen bond degrades and snaps apart, releasing oxygen bubbles into the air.

After this reaction, the free oxygen atoms search for something else to bond with. Often, the oxygen atom will steal electrons from the atoms that make up an organism’s cell walls and DNA, which damages the walls and harms the organism.

So, hydrogen peroxide isn’t just poisonous and potentially lethal to worms, bacteria, and fungi. It’s toxic to any organism with cells, including humans.

However, it’s most effective for killing smaller organisms with few soft or weak cell walls since these usually have fewer cells.

Hydrogen peroxide can quickly destroy one-celled organisms, but it takes much more peroxide to kill large animals. For example, it takes tons of peroxide to kill a human since humans have 37.2 trillion cells, and peroxide can only take down one cell at a time.

Hydrogen Peroxide Resistance in Bacteria and Worms

Some bacteria, fungi, and insects are resistant to the effects of hydrogen peroxide. The best evidence for this comes from a 2020 study on how organisms such as bacteria and worms neutralize hydrogen peroxide.

This study found that some worms can produce a specific hormone that makes them resistant to the damaging effects of hydrogen peroxide. Other organisms may produce catalase, which actively degrades the peroxide. This resistance does not make them immune to high concentrations of peroxide, but it does help them survive after exposure.

However, the most groundbreaking finding was that, when exposed to high concentrations of hydrogen peroxide, worms can survive without releasing their hormones as long as there are hydrogen-peroxide-resistant bacteria nearby.

So, this study proved that hydrogen peroxide will not always work for killing worms in your soil — at least, not with just one treatment and not with hydrogen peroxide alone.

Still, it will work if your worms cannot produce the peroxide-resistance hormone and you do not have resistant bacteria in your soil.

Pests and Diseases That Hydrogen Peroxide Eliminates

Hydrogen peroxide works against a broad spectrum of pests and infections that often threaten plants, making it a staple in gardening and indoor plant care.

Here are some examples of common pests and diseases that hydrogen peroxide will eliminate:

Gnat larvae, including fungus gnats
Parasitic nematodes
Cutworm larvae
Aphid, mealybug, mite, and thrip eggs and larvae
Root rot, white powdery mildew, and most fungal infections

Does Hydrogen Peroxide Kill Beneficial Worms and Bacteria?

Hydrogen peroxide kills beneficial worms and bacteria in the soil. For that reason, you should only use hydrogen peroxide as soil treatment if the harmful bacteria and worms are so pervasive that they are threatening your plant’s life.

Although peroxide will kill parasitic worms, harmful fungi, and plant-destroying bacteria, it will also kill all beneficial organisms in your soil.

So, suppose your peroxide treatments are effective enough to remove the worms threatening your plants. In that case, they will also be effective enough to kill the bacteria, fungi, and worms that help to aerate and balance your growing media.

Because bacteria and worms are critical for preventing infestations of unwelcome pests and infections, it’s vital only to use hydrogen peroxide soil treatments as a last resort.

The Pros and Cons of Using Hydrogen Peroxide In Soil

So, now that we’ve gained a better understanding of how hydrogen peroxide will affect the worms and other organisms in your soil, let’s go over the general pros and cons of treating your planting media with peroxide:

The Pros

It is an effective fungicide and pesticide.
It’s gentle and safer than most pesticides and sterilizing chemicals.
It poses a low risk to your plant’s root system since the roots happily absorb excess oxygen.
It assists plants in absorbing potassium from the soil.
It damages insect and worm eggs in your soil.

The Cons

It does not always work for resistant bacteria and worms.
It also eliminates the good bacteria, fungi, and worms in your soil.
It takes many reapplications to eliminate worms from the soil.
If you do not dilute the hydrogen peroxide, it may cause burns on your plant’s roots or leaves.

How To Use Hydrogen Peroxide To Kill Worms in Soil

Now that you know what a hydrogen peroxide soil treatment can do for your plants, let’s look at the best methods for sterilizing and de-worming your soil with this versatile cleaning solution.

Here’s how to use hydrogen peroxide to kill worms in the soil and disinfect your planting media:

Isolate your infested plants. Whether you want to eradicate nematodes, worms, gnats, or infections, always start by isolating your infested or infected plants. Isolating these plants will help you prevent the worms from spreading, saving you tons of work in the long run. Keep them in a window far from other plants for the best results. I recommend placing them in a bathroom or kitchen since these areas are easy to clean.
Choose your peroxide percentage. Your peroxide concentration percentage (usually either 3% or 35%) will significantly affect how much water you will need to mix it with before treating your soil. Higher percentages call for more dilution, while lower concentrations have already been diluted quite a bit and require less water. Go with the weaker 3% solution for small gardens or single-plant infestations.
Mix your hydrogen peroxide solution. If you use a 3% solution, mix 3 cups of hydrogen peroxide with one gallon (3.79 L) of water. For 35% hydrogen peroxide, mix two teaspoons of peroxide with one gallon of water. If unsure about the measurements, always err on the side of less peroxide to more water.
Soak your soil. As I mentioned above, hydrogen peroxide will work immediately on those worms, bacteria, and fungi that are not resistant to it. However, it may take prolonged exposure for the resistant organisms to die off. So, thoroughly soak your soil in the peroxide solution and let it sit for around a week before your next watering.
Monitor your plant and soil. Keep an eye out for more worms, gnats, and fungal growth as you wait to see the effects of your soil treatment. If you soaked the soil in a potted plant or a garden bed, keep an eye on the leaves and look for brown or black leaf tips and light brown scales on the foliage. If you notice these “burns” on your plants’ leaves, dilute your peroxide more next time.
Re-treat your soil if the problem persists. If you still have worms, gnats, or fungi growing in your soil, you can re-treat your soil with peroxide. You should only apply a second soak after waiting around one to two weeks.

When re-treating your soil, use the same peroxide solution you used the first time. However, you should dilute the hydrogen peroxide more if you notice damage to your plant’s foliage.

In addition, after you have eradicated your soil’s pests, I recommend re-introducing beneficial bacteria into the media. You can use simple compost or fresh topsoil to help rebalance your dirt, and you can also introduce good worms such as earthworms to keep your soil aerated.

Final Thoughts

Hydrogen peroxide can be a helpful tool for killing worms and many other pests and infectious organisms in your soil. However, some organisms are resistant to hydrogen peroxide, so you will need to re-treat your soil a few times to see favorable results in some cases.

Still, remember that hydrogen peroxide also kills beneficial bacteria and worms, so only use it as a last resort and ensure that you re-introduce healthy worms and compost into your soil after treating it with hydrogen peroxide.