The Benefits of Hydrogen Peroxide (H2O2) for Plants and Hydroponics


The Benefits of Hydrogen Peroxide (H2O2) for Plants and Hydroponics

If you want to boost the overall productivity of your crops, taking advantage of chemistry can give you complete control over your grow system while giving you a decisive edge over pests and microbes as well. 

What is Hydrogen Peroxide (H2O2)?

Hydrogen Peroxide (H2O2) is a chemical compound. It is the simplest form of peroxide and belongs to a family of compounds in which there is a single bond between two oxygen atoms. Commonly recognized for its bleaching abilities, it is found in detergents, hair bleaching products, and disinfectants. While it was first discovered in 1818 by French chemist Louis Thenard, it's highly unstable nature halted effective industrial production until the 20th century.

Hydrogen Peroxide is fairly common to find in nature and can be traced in limited quantities within the human body as well. While it can be toxic to humans and animals in concentrated forms, it has a uniquely beneficial effect on plants. 

Does Hydrogen Peroxide Cause Any Harm to Plants?

As we all know, there can be too much of good thing. However, Hydrogen Peroxide solutions for plants are typically diluted to lower the risk of overexposure. H2O2 is recognized by the EPA so you can be confident in its safety. Hydrogen Peroxide is made up of the same atoms as water with the exception of that extra oxygen molecule. That extra oxygen molecule is what gives H2O2 the majority of its beneficial properties. Provided the strength of the chemical compound is appropriately diluted, H2O2 is perfectly safe for use with plants. The most common solution is a 3% solution but solutions can go up to 35%. A 3% solution can easily be found at any grocery or drug store. 

The Benefits of Hydrogen Peroxide

The significance of Hydrogen Peroxide when it comes to playing an active role in your garden can be attributed to multiple properties of the chemical compound.

Anti-Chlorine Action

Concentrated Hydrogen Peroxide was shown to be incredibly effective in removing chlorine from water in some wastewater treatment processes. Those that are familiar with hydroponics know the value of having pure water. H2O2 provides an efficient solution to the tricky process of removing chlorine from water.


In its purest form, H2O2 exists as a pale blue liquid, slightly thicker than water. Since the chemical compound is essentially water with an additional oxygen molecule, it naturally decomposes into separate water and oxygen molecules without a stabilizing agent. For young roots, the availability of oxygen molecules is vital when it comes to stimulating growth. Many hydroponics systems feature higher temperatures to lead to a  reduction in the number of oxygen molecules within water. Successful systems employ the use of H2O2 breakdown to counteract this effect.

Anti-Microbial Defense

When placed under acidic conditions, Hydrogen Peroxide forms a Hydroxyl Radical. These compounds have devastating effects on organic tissues and microbes alike. As H2O2 releases a single oxygen molecule as part of its natural decomposition, a potent anti-microbial action is the result. Considered to be environmentally-friendly by the FDA, H2O2 is a successful defender against a wide variety of bacteria, viruses, and common pests. 

Biological Signals

H2O2 serves as a signaling agent for many biological processes. Cell signaling is a constant act of communication between living cells in both plants and animals. These signaling agents have a specific impact on that communication process by stimulating cells to behave in a certain way. H2O2 is known to affect plant defense mechanisms by creating catalase at the routes. The chemical compound is also believed to increase nutrient intake at the roots. Research for this benefit among many others is currently being explored. 

Incorporating Hydrogen Peroxide into Your Garden

H2O2 can be used for any of the following in your garden:

  • Pest Control
  • Pretreating Seeds
  • Treating Root Rot
  • Infection Prevention for Damaged Trees
  • Foliar Spray to Kill Fungus

Hydrogen Peroxide has been used much like a general fertilizer, by either being added into water or sprayed directly onto foliage. It’s important to note that H2O2 is not technically a true fertilizer but it can help boost the growth of your garden by encouraging healthy root growth. The additional oxygen molecule found in the chemical compound helps plant roots better absorb nutrients from the surrounding soil. A boost in root’s efficiency in absorbing nutrients can lead to faster, healthier, more vigorous growth over time. Hydrogen Peroxide also discourages unwanted bacteria and fungi that may be lurking in your garden. 

How to Use Hydrogen Peroxide in Your Garden

To take advantage of the added boost of oxygen while protecting your plants from common pests, add 1 teaspoon of a 3% solution to a cup of water in a spray bottle. This treatment can be used to directly mist your plants or it can be used when pretreating seeds to control fungal infections.

For plants currently experiencing root rot or a fungal infection, use 1 tablespoon of a 3% solution for every cup of water. The water and H2O2 mixture can be made in advance, just be sure to store it in a dark, cool place as exposure to sunlight diminishes potency over time.

If you’re looking to cover a large area, it can be more economical to purchase a 35% H2O2 solution. When creating this solution, you’ll want to mix one part of Hydrogen Peroxide for every ten parts of water. This will equal one cup per four square feet of garden. Mix the solution into a large watering can or sprayer. Water at the base of plants and avoid directly spraying any foliage. Re-spray the solution after every rainfall or as needed. Be careful when using this potent solution. High levels of Hydrogen Peroxide can bleach or burn skin. 

Using Hydrogen Peroxide in Your Hydroponic System

Hydrogen Peroxide is typically added in small quantities to the central reservoir within your hydroponic system. After adding the chemical compound to your central reservoir, here’s how it works:

  • The chemical compound will break down and separate into water and oxygen. A single oxygen atom is a free radical.
  • As a free radical, an oxygen atom is a volatile agent and can react in a variety of different ways.
  • If the oxygen atom comes in contact with an organic cell, such as bacteria or a virus, it will damage and destroy it.
  • If the oxygen atom comes in contact with another oxygen atom, they will bond together to form an O2 molecule. O2 molecules are essential for healthy plant roots.
  • Whole H2O2 molecules will react with any free chlorine in water to form O2 and Hydrogen Chloride.

Using H2O2 in a hydroponic system is a great way to grow healthy, thriving plants. Growing plants with hydroponics means you can easily spot problems such as a lack of nutrients or bacteria growth due to the warm atmosphere. The harmful bacteria present in hydroponic gardens typically thrive in water with low oxygen content. H2O2 boosts the amount of oxygen in your water and can combat low oxygen levels in warm or room temperature water. It will kill off bacteria too, so if you find any fungus or mold spores in your hydroponic system, you’ll be equipped with a quick solution. You should always aim to keep your solution in a black bottle as light makes the chemicals break down faster.

Hydrogen Peroxide for Soil Aeration and the Treatment of Root Rot

Having a solid system when it comes to soil aeration is important for any garden setup. Making sure that there’s plenty of space for air and nutrients to travel through soil and reach the roots of your plants is the best way to see your plants flourish. If your soil is too compact, your plants could quickly die. If roots are looking compacted and are tangled together, your soil doesn’t have enough aeration and your plant is struggling. Poor aeration can also lead to a buildup of toxins and disease.

Root rot is a common symptom of soil becoming too compact. Typically seen in plants that have been overwatered, root rot is the most common cause of decay for plants and shrubs. The tricky aspect of root rot is that it can sit in soil for years, even if there hasn’t been anything planted in it. It can be incredibly difficult to treat when soil becomes waterlogged or compact.

Root rot can be difficult to spot above ground when there’s still time for preventative action. Signs of serious root rot will eventually appear with yellowing leaves and branches falling off completely. While root rot can be devastating to your garden, it can be treated with Hydrogen Peroxide.

Using a 3% solution, carefully pour the H2O2 around the base and roots of your plant to kill off bacteria. H2O2 will also help to aerate your soil and prevent future cases of root rot. A healthy root system should be long and untangled with fuzzy white growth on the main root for absorbing water and nutrients. 

H2O2 for Seeds, Germination, and Root Development

Everyone knows that seeds do best if they are soaked in water first, but did you know that using hydrogen peroxide in your water solution will help them germinate faster? H2O2 is also a great resource for killing off any bacteria that your seeds may have picked up on their journey to your garden. Pour a 3% solution into a small, watertight container and leave the seeds in there for around 4 hours. This process will kill off unwanted bacteria without any negative effects on the seeds themselves. After soaking, rinse off the seeds with clean, fresh water and leave them to dry on a clean towel. 

Hydrogen Peroxide can also accelerate germination. Just a minute or two in a weak solution can dramatically increase how fast your seeds will sprout. Putting the seeds in a container that allows water to pass through, such as a sieve or a mesh bag. Unlike bleach, Hydrogen Peroxide removes any bacteria without damaging the seed itself. Continue to aim for a solution of one teaspoon for every cup of water that the seeds are soaking in. It’s important to note that lower concentration solutions will take longer for results to show. Due to this, you should try to rinse your seeds with water and then begin the germination process as soon as possible. Use a thin layer of wet kitchen towels or sprinkle some potting soil into a seedling tray. Most seedling trays are often made of cardboard or other absorbent material which will keep the seeds moist until they are ready to sprout. Read your seed instructions carefully and be sure to keep them at a proper temperature. Warm and moist is best and, generally, seeds thrive in a warmer climate so consider putting them in a seed propagator or greenhouse if possible.

If your plants are looking limp and lifeless, then give them a healthy refresh with a dose of Hydrogen Peroxide. While you can use it in the earliest stages of your plant’s life or to deal with fungal growths, it is also great to incorporate into any stage of their growth. A Hydrogen Peroxide solution can be sprayed or absorbed straight into the soil to help encourage your plant’s roots to function as effectively as possible. And of course, watering plants with a Hydrogen Peroxide solution will introduce more oxygen into your soil. This boost of oxygen encourages roots to take in extra nutrients and water and it will help an ailing plant get back on track. For larger areas or whole garden treatments, use two teaspoons of 35% Hydrogen Peroxide for every one gallon of water and incorporate the treatment on your garden every other time you go out to water your plants.

Summary: The Main Advantages of Hydrogen Peroxide for Plants

As a recap, the main advantages of incorporating the use of H2O2 into your garden or hydroponic system are as follows:

  • Fights against bacteria, viruses, and other common pests
  • Treats and prevents root rot and fungi
  • Improves oxygen content in water
  • Stimulates root growth and nutrient absorption
  • Removes chlorine from water
  • Boosts overall plant growth and health 
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