In an organic garden, we are always trying to find ways to deal with pests, problems and plants that do not involve the use of synthetic chemicals that can harm the environment.

This is where hydrogen peroxide can potentially come in.

As you will learn in this article, hydrogen peroxide is a natural material, and can be perfectly eco-friendly and sustainable when used correctly.

It will not always be the best solution. And you should always use it with caution. However, when diluted to the right concentrations and used in appropriate ways, there are a number of uses for it in the garden.

The best way in an organic garden is always to take a holistic approach. By choosing the right plants, tending them well, taking care of the soil and boosting biodiversity in the ecosystem wherever we can, we can help keep things in balance. But every now and then, we may need a little extra intervention to keep things on track.

Make sure you don’t view hydrogen peroxide as a panacea. Always make sure you use it with care if you use it at all. But read on and you will discover that in certain ways, it can be very useful in your garden.

What is Hydrogen Peroxide?

Hydrogen peroxide is a naturally occurring chemical compound with the formula H2O2.

In other words, it has the same chemical composition as water, but with one additional atom of oxygen.

Very pale blue in its pure form, we are more used to seeing this in its diluted form, as a clear liquid slightly more viscous than water.

In low concentrations, people commonly use it as an oxidizer, antiseptic for cuts and scrapes, or as a bleaching agent. Highly concentrated, people use it as rocket fuel.

Alexander von Humboldt reported one of the first synthetic peroxides, barium peroxide in 1799. In 1818, Louis-Jacques Thénard recognized that this compound is useful in the preparation of ‘oxygenated water’ which later became known as hydrogen peroxide.

An improved version of his process, using hydrochloric acid and sulfuric acid allowed scientists to synthesize hydrogen peroxide from the end of the 19^th Century until the middle of the 20^th Century.

Pure hydrogen peroxide was first obtained by Richard Wolffenstein by a process of vacuum distillation in 1894.

Today, hydrogen peroxide is almost always manufactured through the anthraquinone process, patented in 1939. Though there are several ways to produce hydrogen peroxide directly from the environment, none can yet be used on an industrial scale.

This chemical compound is very unstable. In the presence of light, it will decompose. For this reason it is usually stored with a stabilizer in a weakly acidic solution in a dark colored bottle.

Hydrogen peroxide is found naturally occurring in biological systems – it is present in surface water, rainwater, and even in the human body. Consumers usually have access to solutions in water, which are typically at concentrations of 3 and 6%. Stronger concentrations are also available, largely for laboratory use.

Is Hydrogen Peroxide Eco-Friendly?

It is very important to understand that, like so many other substances, hydrogen peroxide will have very different properties depending on its concentration, and how much of it is used. So many things can be harmful if used in excess, and the same is most definitely true of using hydrogen peroxide in the garden.

As a naturally occurring compound, which degrades naturally and quickly into water and oxygen, hydrogen peroxide is often a far more eco-friendly alternative to more polluting and harmful synthetic garden treatments.

But since hydrogen peroxide is synthesized in labs, we need to think about the entirely lifecycle of the product, and this will lead us to question whether it really is the most eco-friendly option.

The process involved in deriving H202 involves the use of a palladium catalyst. Palladium is a critical material, difficult to obtain and of course finite. Check out this link to find out more about this and other environmental concerns surrounding hydrogen peroxide production.

Is Hydrogen Peroxide Safe to Use?

It is also important to understand that you must dilute it before use. Remember, the highest concentrations are quite literally rocket fuel. And while low concentrations can be good for plants (in some ways outlined below), stronger concentrations are used as weed killer and can kill your plants and harm the soil ecosystem.

When H2O2 breaks down, ‘free radical’ oxygen atoms and water molecules are produced. The oxygen atoms bond to one another forming oxygen (O2), and some will bond with other minerals.

In very dilute solutions, this additional oxygen can be beneficial. And soil micro-organisms can often utilize those minerals better because of the formation of those bonds.

But it must be a very dilute formation, since even a 0.5% dilution can destroy fungi and bacteria. Sometimes, this might be a good thing (as we’ll discuss below). But when used indiscriminately in the soil, it can kill beneficial fungi and bacteria as well as those we don’t want.

Safety is Key

In a low concentration, hydrogen peroxide is generally safe for people as well as plants. But it is important to be very careful and to treat it with respect.

As a very unstable compound, hydrogen peroxide can explode if exposed to heat. (It is even used to make explosives). It is therefore important that it is stored securely, in a cool, dark place away from direct sunlight or other heat sources.

Higher concentrations can lead to severe burns. It is a good idea to wear rubber gloves if you are dealing with higher concentrations before dilution. While you may be familiar with the use of hydrogen peroxide on the skin – to treat cuts and wounds – this is no longer recommended.

And it should never, ever be swallowed or ingested. Even in dilute amounts, it can cause issues in the human body. Of course, keep it away from children and pets.

10 Ways To Use Hydrogen Peroxide In The Garden

1. To Boost Oxygen Content in Poorly Aerated Soil

The first way in which hydrogen peroxide can come in handy is in the remediation of degraded soil. When soil has become seriously compacted, plant growth will suffer due to the lack of oxygen.

Heavy clay soils can be particularly prone to compaction and poor aeration. Implementing no dig gardening techniques and adding plenty of organic matter is usually the best way to combat this problem – though where the problem is more pronounced this will take time.

In the short time, judicious applications of hydrogen peroxide around plant roots could help boost yield and tackle the problem.

2. To Treat Root Rot

In particular, hydrogen peroxide can be used to target specific problems that crop up when soil aeration is poor. For example, it can be used to treat root rot.

Phytophthora root rot is harbored in the soil, and is challenging to treat. A very dilute mix of hydrogen peroxide can be poured carefully around the roots of affected plants.

3. To Treat Other Fungal and Bacterial Infections

Hydrogen peroxide can also be used topically to treat other plant infections. It can be an effective treatment for problems such as powdery mildew, fungal diseases and mold, and can cleanse soil of ‘bad’ bacteria.

Using a drench of water and hydrogen peroxide can help to cleanse the growing medium of plants grown in containers. And heavy watering could also help plants grown in the ground.

Just remember – free radical oxygen atoms can also result in the unhealthy depletion of beneficial bacteria and fungi in the soil biome. So if you consider this course of action, it should only ever be considered where other solutions have fallen short.

Negative effects will usually be short lived. But you may wish to consider re-introducing beneficial microbes and nutrients.

4. To Repel A Range of Pests

Spritzing the leaves of your plants with a low-percentage hydrogen peroxide solution can repel a range of common insect pests. This is in addition to keeping disease at bay.

Aphids and a range of other sap suckers will tend to stay away. They will be repelled by the pungent smell of this compound. And it will also kill eggs when sprayed directly onto them.

Just remember, this solution may also repel or kill the eggs of insects you do want in your garden. So like other repellents and organic pesticides, it is better than synthetic alternatives. But it should only ever be used as a last resort.

5. To Disinfect a Growing Medium

If you are having a lot of problems with disease when growing plants in pots or containers, the problem may be the growing medium you have chosen to use.

Choosing a potting mix with unknown providence might mean that you are inadvertently introducing pathogens into your garden.

Drenching the growing medium with a dilute hydrogen peroxide mix before use can help you to avoid importing issues.

6. To Soak Seeds Before Sowing

Another source of disease in your garden can be the seeds you choose to grow. If you always choose seeds that come from a reliable source – be it your own garden, if you collect your own seeds, or a trusted vendor – you should not have any problems. But soaking seeds in a water and hydrogen peroxide solution prior to planting can help ensure that they are pathogen free.

Soaking seeds with hydrogen peroxide solution may also aid in increasing germination rates, and could increase your success rates. So this is another reason why you may like to consider taking this step.

7. To Disinfect Pots, Containers and Garden Tools

As an effective disinfectant, hydrogen peroxide is used to clean a range of items and surfaces around your home. It is also useful to effectively clean pots, containers and garden tools.

Good garden hygiene is key to avoiding the spread of diseases. Particularly if you have had a serious disease outbreak. So disinfect everything that came into contact with affected plant materials. This can help you make sure that you don’t have a recurring problem year after year.

8. To Rinse Home-Grown Produce

Simple water, or Castile soap solution can usually be perfectly sufficient to clean home-grown produce before you bring it inside. But if you are particularly concerned about pathogens like e-coli and salmonella, you can use hydrogen peroxide as a dilute rinse.

Use a rinse to disinfect all your produce before you wash it and eat it.

9. To Treat a Water Supply

Hydrogen peroxide also replaces more damaging chemical bleach or other such products in treating a water supply.

If you rely on well water, or a rainwater harvesting system, there are a number of ways to make sure that the water is free from pathogens and safe to drink and use.

But before you decide to use hydrogen peroxide, I would always highly recommend that you look into greener water treatment alternatives – from gravel, sand and charcoal filters, to phyto-remediation with plant life (reed beds etc.), to UV sterilization.

10. To Improve Results in an Hydroponic or Aquaponic System

Finally, hydrogen peroxide also helps gardeners to improve a hydroponic or aquaponic system. Hydroponics is growing plants in water rather than soil. And aquaponics integrates hydroponics with aquaculture (keeping fish). These closed loop systems can be very eco-friendly and effective. But they can also have issues.

The addition of hydrogen peroxide to the water can help keep it oxygenated. However, I would recommend speaking with an expert in the field for advice on exactly how and where to use it, and in what quantities.

Hydrogen peroxide is an interesting compound, with a number of beneficial properties. But the very things that make it beneficial can also cause problems if it is used incorrectly. Plus the sustainability credentials of the substance certainly leave something to be desired.

So if you do choose to use it in your garden, don’t go overboard. And be sure to think very carefully before you do.