Plant fungus treatment with Hydrogen Peroxide

Hydrogen Peroxide for Plant Fungus

Hydrogen peroxide is one of the most well-known disinfecting tools known. It is an organic compound that is pretty much water with extra oxygen. Morphologically, hydrogen peroxide is a colorless and odorless liquid, and it’s widely used in medicine and households.

So what is the concept of using hydrogen peroxide for plants? The extra oxygen hydrogen peroxide has, is loosely bound and easily dissociates. Further, it provides a versatile tool for the processes that involve oxidation, disinfecting, and even bleaching.

Therefore, the question arises that if hydrogen peroxide is so effective in getting rid of the microbes, can it be used against fungal infections too? Because the fungi are one of the most stubborn organisms to infect a plant. And most fungal infections result in the complete loss of crop yield.

Before we answer that question, it is important to familiarize ourselves with hydrogen peroxide’s action on plants. And determine in the light of research if it’s safe for plants or the oxidation properties are harmful to the normal flora. So without further ado, let’s begin!

Hydrogen Peroxide and Plants – The Natural Link

Before we can thoroughly discuss how hydrogen peroxide can be used in getting rid of plant fungus, we have to make sure that the agent is completely organic.

We aim to expose that hydrogen peroxide is not a lab-manufactured plant agent but rather an integral part of the plant’s growth and functioning. All of these facts will be covered in the light of research!

Plants Use Hydrogen Peroxide to Sense the Outside World!

Like human beings, plants are complex organisms that can sense, respond and react to environmental conditions and stress. But unlike us, their way of counteracting is subtle and is based inside the boundaries of the cell wall.

Much of what a plant sense is based on the changes in the chemical compositions outside the cell. Particularly the plant cell wall and its outside matrix (apoplast) contain a set of chemical compounds, which can signal plant cells. These signals are produced in the form of an increase or decrease in their threshold concentrations. Then these changes in concentrations are sensed by the plant cell receptors and precise response is initiated. An example of this would be the reactive oxygen species (ROS).

ROS are vital to plant cell functioning. Plants constantly produce ROS in many different forms, one of which is hydrogen peroxide. These reactive oxygen species reside in the apoplastic matrix.

Recently an article found out the presence of hydrogen peroxide receptors inside the plant cell wall which can indicate its mechanism in plant stimulus. Scientists have also found a clear indication of how ROS (in the form of hydrogen peroxide) can induce the influx of Calcium ions inside the cell which has a myriad of different cellular responses. Some of them include pathogen resistance across the entire plant, growth of pollen tubes, root hairs, and even the opening and closing of stomata!

It Regulates Plant Death!

Cellular death is not a coincidental and sudden process. Instead, every cell is a machine of complex networks and careful regulation of chemical concentrations. Therefore, it is very rare for a cell to go through an unprogrammed cell death naturally. Whenever a cell reaches the end of its life cycle, certain pathways are activated which further allow the activation of cytotoxic enzymes. These enzymes then lead to programmed cell death or apoptosis.

Similarly in plant cells too, a higher concentration of certain compounds can activate cell signaling pathways which ultimately lead to its programmed cell death. One of the key molecules that comes to mind is hydrogen peroxide. H2O2 is both an important signaling molecule as well as a toxic byproduct of cellular metabolism. Therefore, a plant cell keeps the hydrogen peroxide concentration in check under tight homeostatic regulation. Moreover, a cell can sense sublethal doses of hydrogen peroxide concentration and activate death stimuli, from which apoptosis is triggered.

Similarly, a research article points at how exogenously applied hydrogen peroxide can trigger cell death. And at high enough concentrations, it can even lead to necrosis which is the unprogrammed cell death (such as seen in trauma).

Another indication of how hydrogen peroxide can lead to apoptosis is how it leads to an influx of calcium ions inside the cell. At a high enough concentration, calcium ions act as a death trigger to the cell. They start to induce the release of cytotoxic enzymes from mitochondria. These enzymes lead to the destruction of the cell membrane, splicing of genetic material and inactivation of functional proteins, and in turn cell death.

Helps in Plant Development!

The role of hydrogen peroxide inside the cell wall matrix (apoplast) and the influx of calcium ions are hinted at in the previous sections. Now we aim to explore how increased concentrations of ROS and calcium can help in plant growth!

One of the direct ways hydrogen peroxide can help with plant cell growth is by anti-ROS enzymes. These enzymes not only function in removing the harmful free oxidative species from the cell and its vicinity but also promote the formation of growth proteins. In simpler terms, by introducing enough hydrogen peroxide, plant cells can counteract, which in turn release growth enzymes and proteins, establishing that it is still young and has a long life to live. In older plant cells (or at higher hydrogen peroxide concentration), a similar process overhauls the anti-ROS enzymes and releases apoptotic responses instead.

A secondary way of how hydrogen peroxide promotes plant growth and development is via crosstalk between H2O2 and calcium ions. The complete mechanism of hydrogen peroxide-induced calcium response is rather complex. But for the sake of simplicity, you should know that plant cells contain various types of Ca+2 receptors and channels such as Ca+2-ATPases, calcium-binding sensor proteins, and cyclic ADP-ribose. Calcium is a well-known growth promoter and has a vital role in seed germination, leaf de-etiolation, cell polarity regulation, stomatal closure, and immune responses.

Furthermore, free calcium ions inside the cell have shown responses to a wide range of environmental stress like heat shock, drought, light, and salt.

It Promotes Healthy Root Growth!

Another growth-positive response hydrogen peroxide has on plants is promoting root growth and reproductive capacities of plants.

Roots are a vital component of plant structure. They are embedded inside the cultural medium (e.g. soil). They have small projections that are responsible for extracting water and nutrients for the rest of the plant. They do so by intriguing processes such as negative water pressure and osmosis. Therefore, roots are responsible for nutrition as well as providing raw materials for various plant metabolism and processes.

Hydrogen peroxide has friendly relations with the plant’s root. They not only promote the elongation of plant roots but also a complex set of mechanisms that increases the absorption capacities of plant roots. This important function is a result of calcium ion influx.

Therefore, with an adequate amount of hydrogen peroxide, you can promote root growth, polarized growth of pollen tubes, preventing water loss from plants (by closing stomata), and promoting seed germination!

Can You Use Hydrogen Peroxide to Treat Plant Fungus – A Comprehensive Analysis

One of the reasons why plants suddenly look greener in the rainy season is hydrogen peroxide. In the raindrops (especially the first rain of the season), trace amounts of naturally occurring hydrogen peroxide are present. Therefore, hydrogen peroxide is responsible for the growth and cleaning of plants naturally!

But the question is, how effective is hydrogen peroxide in treating fungal infections of plants? These creatures are particularly known for being stubborn. So much so that a fungi colonization on a single plant can cause the whole yield to rot!

What Are the Most Frequently Occurring Plant Fungi?

Before we move on to how you can treat fungal infections in plants, it is important to know what are some of the most common fungal infections in plants. Only then we would be able to determine its causes and how it looks.

White Rusts

This fungal disease is very common in plants that grow in mild temperatures e.g. Asian leafy brassicas.

You can determine if your plant suffers from white rusts if it has white blisters and swellings on leaves and heads. Moreover, the blisters consist of masses of white dust-like spores. Plants affected by white dust do not survive.

Black Root Rot

As the name suggests, this disease affects the root of plants. After the infection, the roots appear as dead and blackened masses.

Blackroot rot commonly occurs in cool, low-aerated soils which have high moisture. Lettuce, beans, and cucurbits are some of the common victims of this type of fungal disease.

Sclerotinia Rots

These are special rots caused by the fungus S. sclerotiorum, and commonly affects vegetable crops. More particularly, those having windy, cool, and humid weather with wet soil.

Water-soaked rotting of stems, leaves, and sometimes fruit is seen in this fungal infection. They manifest as fluffy, white, and cottony fungal growth which contain hard black pebble-like deposits. These rots may persist as sclerotia remain in the soil for up to 10-15 years!

Powdery mildews

Mildews are a subclass of fungi. They commonly affect plants in moderate temperatures with relatively dry conditions.

Mildews can affect a wide range of hosts, some of them include greenhouse crops, cucumber, melons, pumpkin, zucchini, parsnip, beetroot, potato, herbs, peas, and tomatoes.

They manifest as small, white powdery patches on most above-ground surfaces. They usually appear on the underside of leaves but eventually cover both surfaces. Affected parts become yellow, brown and then die as papery remnants.

Downy mildews

Plants that grow under high humidity and cool temperatures (10-16 degrees Celsius) are the ones most likely to suffer this form of fungal infection. Some of the most threatened crops are onions, peas, lettuce, spinach, kale, herbs, and brassicas.

The symptoms for this mildew are very similar to the powdery mildews. However, the former affects plants at higher temperatures while the latter is more cold-temperature oriented.


Clubroot is primarily caused by a fungus known as Plasmodiophora brassicae and it affects plants that grow under warm weather, acidic soil (less than 7 pH), and contain high moisture. Brassica plants are most prone to clubroot disease.

Clubroot is characterized by the large malformed “clubbed” roots which prevent the uptake of water and nutrients. This reduces the potential yield of crops. Moreover, the plants are yellow and stunted and wilt in hotter parts of the day.

Which Plants Are At High Risk?

Although fungal infections can occur in all plants, there are some common variables. Plants that are most prone to fungal infections are the less aerated ones.

Sometimes, overwatering a plant can lead to a shortage of available oxygen for the roots. This occurs when the air pockets present in the soil are filled with water and decrease the aeration of the soil. And it is in this moist and less-aerated environment, fungi thrive.

Moreover, the death of root tissues becomes a feed for decomposing bacteria and fungi. Therefore, increasing the chance of infection in the nearby plants and soil.

Treating Plant Fungi Using Hydrogen Peroxide

If we consider the above information, the cause of root rot is because of less aeration of the soil. And when we talk about aeration, there is not a single agent more competent than hydrogen peroxide.

In addition to the preventive measures, hydrogen peroxide can also be used for treating the fungal infections that commonly occur inside the plants.


The greatest benefit that hydrogen peroxide provides is prevention against fungal infections. When it comes to such types of infestations, it’s coincidental. Normally fungal infections are rare. Therefore, not many fertilizers provide the essential nutrients to combat them. And once a root is infected with fungi and mildews, they spread very quickly to infect all the other plant roots in the vicinity.

The main cause for root rot (fungal infection) is poor aeration of the soil. This can be due to over plantation or overwatering. Once the roots start to die due to lack of oxygen, decomposing fungi start to feed on them. This drastically increases the chance of infection in the nearby roots.

All of this can be prevented by using hydrogen peroxide in the watering plants. Not only does hydrogen peroxide dissociate to provide the essential oxygen for root survival but also decreases the chances for infection by keeping the soil fungi-free.

In addition to the preventive benefits of hydrogen peroxide, it has treatment benefits too. Hydrogen peroxide is an organic compound that is acknowledged by plants. So much so that plant cells have specific receptors for hydrogen peroxide.

Combine that with the fact that hydrogen peroxide has harmless byproducts and is non-specific to its antimicrobial actions. All of these pointers crown hydrogen peroxide as the foremost tool in treating and preventing plant infections, especially fungal infections!


Now that all of the benefits of hydrogen peroxide are stated, the question arises, how effective is hydrogen peroxide in the light of research?

When it comes to the fungicide properties of hydrogen peroxide, an article published in the Journal of Applied Bacteriology gives noteworthy evidence of hydrogen peroxide’s efficiency against bacteria and fungi growth. More particularly the sporicidal properties of hydrogen peroxide which is the primary route of fungi reproduction and growth. The researchers found out that under acidic conditions, hydrogen peroxide can reduce microbial growth by a factor of a million!

Now that we have got the evidence of hydrogen peroxide as a potent fungicide, the next step is to prove if it promotes root growth. And this evidence is provided by an article published by researchers in China. They found out that not only hydrogen peroxide is completely safe for roots, but it also induces the release of calcium ions which promote the growth of roots!

Moreover, according to a research paper published in Nature, hydrogen peroxide improves a plant’s overall immunity. They accomplish this task by stimulating certain enzymes that help give immunity to the plant.

Nonetheless, the research clearly shows that not only hydrogen peroxide is effective in killing fungi but also it promotes root growth and improves the plant’s overall immunity to fight off infections.

How to Use

Now comes the main part, how to use hydrogen peroxide effectively. We have divided the hydrogen peroxide procedure into two parts, one of which is preventing measures, and the other is the treatment.


To prevent root rot or other fungal infections that are caused by a lack of aeration, hydrogen peroxide gives an amazing solution.

You can water your plants using hydrogen peroxide. All you have to do is:

The extra oxygen found in the hydrogen peroxide delivers the much-needed oxygen to the plants!

You can water your plants by mixing hydrogen peroxide whenever you suspect stunt growth or 2-3 times a week for proper aeration of the soil. Make sure not to overdo the procedure as hydrogen peroxide may start to kill essential bacteria e.g. nitrogen-fixing bacteria.


Now comes the part you have been waiting for: killing fungal infections and other plant pests using hydrogen peroxide.

Hydrogen peroxide can control many common pests and insects in the garden (e.g. sap-sucking pests like aphids and mites). It can even kill the eggs and larvae of moths and other dangerous pests by its oxidizing action.

To make this pesticide all you have to do is:

  • Take 2 cups of 3% hydrogen peroxide (or one cup of 6%) per liter of water
  • Pour it in a spray bottle
  • Using gloves carefully spray the parts that show signs of infection
  • For soil pests and fungus gnats, you can spray the solution directly over the soil

And that’s about it! Hydrogen peroxide can also be used in the treatment of mold and powdery mildew fungus which are extremely hard to get rid of.

The great thing about hydrogen peroxide is that you don’t have to do much other than to control its concentrations and follow certain safety precautions.

Safety Precautions to Follow At All Times

When it comes to the safety of hydrogen peroxide, countless articles and experts agree that 3% or less concentration of hydrogen peroxide is safe for human use.

However, this does not dictate that you can be careless in handling this compound. Hydrogen peroxide is a chemical nonetheless and it may have certain side effects if someone is not careful.

The best safety protocol you can follow is to limit the contact of hydrogen peroxide with your skin surface. The use of gloves is one of the ways you can accomplish this task. Moreover, be mindful to not let hydrogen peroxide stay on your skin for more than 5-10 minutes.

Keep hydrogen peroxide away from your nose and mouth. Unlike skin, the internal linings of your nose and mouth are sensitive and hydrogen peroxide can easily irritate the mucosal layer.

One of the safety precautions also includes using hydrogen peroxide in regulated amounts. This umbrella tip covers all the points you need to be careful about. Do not overwater your plants using hydrogen peroxide as it may start to eliminate nitrogen-fixing bacteria in the soil. Similarly do not apply hydrogen peroxide over your plants more than required as it may start to induce cell death.

Last but not the least, make sure that the hydrogen peroxide you are using is not expired. Generally, hydrogen peroxide lasts for 6 months after its opening. Limit the chemical’s exposure to sunlight and air.

Does Hydrogen Peroxide Damage Plant Growth?

As we learned in the previous sections, using hydrogen peroxide may induce programmed cell death in plant culture. However, that only occurs if the concentration of hydrogen peroxide is high and if it’s used in large amounts.

However, the concentration of hydrogen peroxide we use in our procedures is diluted enough to prevent any oxidative damage. As well as strong enough to fight any pathogens or fungi that may be present inside plants. Moreover, the diluted concentration of hydrogen peroxide for plants is recognized by the United States EPA, giving it an absolute safety label.

The best part about using hydrogen peroxide as a disinfecting agent is its organic nature. When hydrogen peroxide comes into contact with air, it decomposes into its products. One of which is the well-known oxygen while the other one is water. Both of these compounds are safe for all living organisms and make hydrogen peroxide a safe and organic cleaning agent!

When it comes to using hydrogen peroxide on plants and its impact on plants’ growth, it is a synergic relation. Not only hydrogen peroxide is safe for plant growth, but it promotes it. We have seen in our previous sections how hydrogen peroxide can help with root growth, water retention, seed germination, and polarize pollen growth.

Therefore, the answer to the question “is hydrogen peroxide safe for plants?” is a resolute yes.

What Concentration of Hydrogen Peroxide is Ideal for Treating Fungus?

Just like many procedures, there is only one concentration of hydrogen peroxide that is most effective in terms of anti-microbial action as well as preserving the safety of the user.

Hydrogen peroxide is available in all types of concentrations. The most common ones are 35%, 6%, 3%, and even 1%. When it comes to disinfecting and getting rid of microbes such as fungi, 3% hydrogen peroxide stands tall. That’s because at this concentration not only hydrogen peroxide is safe to use but it’s effective enough to kill off stubborn fungi and promote plant growth.

Is Hydrogen Peroxide for Plant Fungus a Cost-Effective Option?

Another fact that allures people to use hydrogen peroxide is how cost-effective and easily available it is. When compared to other disinfecting such as bleach and ammonia, hydrogen peroxide provides a much better cost-to-use ratio. That’s because hydrogen peroxide is highly efficient in killing germs. Moreover, hydrogen peroxide does not liberate any harmful byproducts that may hinder the process.

It provides hydrogen peroxide of all concentrations. Moreover, if you order right now, you can avail of a 35% discounted price on 3% hydrogen peroxide!

The Bottom Line

Fungal infections are one of the most infamous plant infections. The reason is how stubborn they are to get rid of and the plant is most likely to die if you try to get rid of fungal growth using chemicals.

However, hydrogen peroxide again stands tall when it comes to doing the impossible. In this case, the reactive oxygen of hydrogen peroxide can get rid of all types of microbial growth, including fungal growth.

Moreover, unlike other chemical disinfectants, hydrogen peroxide is completely organic and does not have harmful byproducts. In addition to that, research has shown how hydrogen peroxide is a part of a plant’s metabolism and how it promotes root, seed, and stem growth in plants.

Therefore, if you suspect a fungal growth in your vegetables, order a set of hydrogen peroxide bottles today!

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