Hydrogen Peroxide For Garden Plants: How To Use (H2O2) In The Garden

Pinterest Hidden Image

Everyone is familiar with the use of hydrogen peroxide as a topical antiseptic and a personal care product.

hydrogen peroxide use in the gardenPin

However, most people are unaware of the fact that hydrogen peroxide a simple substance has amazing benefits and is something of a miracle product when it comes to gardening. In every phase and type of gardening, hydrogen peroxide can be extremely useful and helpful.

In this article, we explore the many reasons why a hydrogen peroxide solution may just be the gardener’s best friend. Read on to learn more.

For All Hydrogen Peroxide For Plants Users – Handle With Care!

In addition to health and beauty applications, H2O2 has many household cleaning uses, such as working as a bleaching agent or for first aid applications.

It’s important to note: It is a valuable and generally safe product. However, it does possess corrosive and combustible qualities. Always use hydrogen peroxide in a diluted form and handle it with care.

The best container would be the one used in hydrogen peroxide production.

But you can also use a safe spray bottle for a more controlled use but it should be made of compatible materials. Always keep hydrogen peroxide out of reach of children.

Store hydrogen peroxide away from sources of heat. Finally, always check the expiration date before using.

H2O2 occurs naturally. However, the commercially produced product is not considered organic. Even so, when using it in your garden, it breaks down to become water.

For this reason, it makes hydrogen peroxide a very environmentally friendly alternative to pesticides, fungicides, and chemical fertilizers.

Its Chemical Makeup… Very Similar To Water

Water’s chemical name is H2O. Two atoms of hydrogen and one atom of oxygen make tap water.

Is Hydrogen Peroxide Safe for Plants?

Hydrogen peroxide’s chemical compound name is H2O2. Its makeup includes two atoms of hydrogen and two atoms of oxygen. It is that difference that makes it so useful as a garden aid.

Hydrogen peroxide is found naturally occurring in biological systems – it is present in surface water, rainwater, and even in the human body. Hydrogen peroxide is safe for plants when used correctly.

Spraying hydrogen peroxide on a plant using a spray bottle.Pin

Oxygen can help plant roots absorb nutrients from the soil. Oxygen is the nemesis of a number of diseases and undesirable organisms. Among them are:

Properly diluted hydrogen peroxide provides an extra dose of oxygen levels to plants and helps fight off these unwanted invaders.

How Can You Use Hydrogen Peroxide On Plants?

There are myriad uses for H2O2 in gardening. Such as:

  • Mold & Mildew Preventative & Treatment
  • Hydrogen Peroxide for Root Rot Prevention & Treatment
  • Infection Preventative
  • General Liquid Fertilizing Program
  • Seed Sprouting
  • Pest Control

Can You Use H2O2 Full Strength?

How much hydrogen peroxide is for plant growth?

It is wise to remember that less is more when using hydrogen peroxide concentration in your garden soil. It must be diluted significantly to be safe for use. The right amount will benefit your plants, and too much will harm them or even kill them.

Most gardeners begin with the lowest concentration of the product to be had – 3%. Even this must be diluted for safety. Here are some guidelines:

1. General-Purpose Dilution

A combination of a single teaspoon of hydrogen peroxide in an 8-ounce cup of water makes a good hydrogen peroxide solution for the following tasks:

This light hydrogen peroxide mixture also acts as a preventative against pests and bacterial and fungal infections such as root rot.

How much hydrogen peroxide per gallon of water? The above mix translates to 2.6 oz or 15.3 tablespoons per gallon of water.

2. Bacterial, Fungus & Infestation Treatment

If you are treating and caring for a sick succulent jade plant dropping leaves or one infested with pests, increase the amount of H2O2 to one tablespoon per 8 ounces of parts water.

You can make up either of these nutrient solutions in advance to keep on hand to use quickly and easily. Just be sure to store your mixture in a dark-colored container with a tightly fitting lid. Keep it in a well-ventilated, cool, dark place.

Frequency Of Treatment

As a general rule, you should thoroughly drench your healthy plants with a preventative mixture following every rainfall. A daily drenching for 3-5 days should suffice if dealing with ill or infested plants. Keep a close eye on your plants and let your best judgment guide you.

10 Ways To Use Hydrogen Peroxide In And Around The Garden

Here are ten excellent applications of this simple miracle product:

1. Create A Sterile Growing Medium

When starting seeds or propagating cuttings, use a sterile growing medium such as vermiculite or perlite for best results. However, as a thriftier alternative, you can sterilize river sand with food-grade hydrogen peroxide.


Use H2O2 to sterilize your potting soil or homemade cactus potting mix.

Hydrogen Peroxide Soil Treatment or Drench Here’s how:

Place the soil or sand in a watertight container and soak it completely with a 3-6% hydrogen peroxide mixture. You will want to let the mixture sit overnight.

Check on it and turn it a few times to ensure all the soil is thoroughly drenched. This treatment will kill off pathogens, nematodes, and their eggs.

2. Sanitize Your Seeds For Sprouting

If your seeds are contaminated with pathogens, they will kill off your seedlings. To prevent this problem, soak seeds in heated 3% hydrogen peroxide for a period of five minutes.

Rinse the seeds at room temperature, running water for a full minute to remove the peroxide before planting. This method can also be used when sprouting seeds to grow edible sprouts.

3. Speed Up Germination

Treatment with hydrogen peroxide nearly doubled seed germination of the Atlantic white cedar (Chamaecyparis thyoides).

The soaking method described above will help seeds germinate quicker thanks to the extra oxygen atom contained in H2O2. This treatment will increase the germination rate. 

Sprouting is a very oxygen-intensive process, and using hydrogen peroxide is an excellent way to help your seeds get the very best start.

After sowing seeds, water them with the weak dilution (1 tsp H2O2 + 1 cup H2O) for the first week. This will give them a boost and help them germinate quickly.

4. Grow Strong Plant Roots

Extra oxygen also helps promote good plant root growth. It is always a good idea to have well-aerated soil; hydrogen peroxide can help meet this goal by delivering extra oxygen molecule.

Watering with a light mixture can help introduce oxygen, even in compacted or clayey soil.

To make a large batch of treated water, combine the following:

  • One Pint of 3% Hydrogen Peroxide
  • One Gallon of Water

Water mature plants with this solution once time a week. Be sure to soak the area around the roots thoroughly. You can also use this dilution strength when transplanting and starting root cuttings.

5. Treat Powdery Mildew Fungus

If you’ve noticed a white powdery substance on the leaves of your summer vegetables, chances are its powdery mildew.

To make a pint of fungal treatment spray, mix 4 tbsp Hydrogen Peroxide with 4 cups of water. This makes an excellent treatment for plants that show symptoms of fungal infections such as powdery mildew.

Remember that hydrogen peroxide can burn sensitive tissues, so it is always best to use a 3% solution in dilution when treating plants.

Always test your hydrogen peroxide solution on a small area before applying your spray.

6. Treat Bacterial Rot

Bacterial infections can be the death of a wide variety of plants. If a plant is injured by inclement weather, poor pruning, or damage caused by insects or disease, bacteria can get a foothold and cause severe illness or death.

You can help prevent this with regular foliar spray of an H2O2 solution.

This is especially wise after pruning knockout rose bushes and trees for example. It’s also smart to prepare tubers and bulbs for winter storage by dipping them in a hydrogen peroxide solution and allowing them to air dry thoroughly before storing.

7. Repel Insects

A good H2O2 solution has a strong oxidizing effect that deters various pests, such as Aphids, spider mites, and other sapsuckers, that destroy their eggs.

Sap-sucking insects such as aphids are especially sensitive to this concoction, and moths are also strongly affected.

Fungus gnats also die upon contact with food-grade hydrogen peroxide.

8. Treat Your Hydroponic & Aquaponic Gardens

The right amount of H2O2 adds oxygen to the water and benefits plant and fish life.

Root rot treatment with hydrogen peroxide:

It also helps guard against root rot, which can be quite problematic in aquaponics and hydroponics.

Because hydrogen peroxide breaks down to become water, it is quite a bit safer than chemical antiseptics usually used to combat fungal infections.

Related: Read our article on Hydrogen Peroxide for Root Rot

9. Use Hydrogen Peroxide Mix As A Disinfectant

Hydrogen peroxide can disinfect your tools, seed trays, pots, and surfaces in your greenhouse or potting shed.

The best form for this purpose is a 6-9 percent solution. You can use this product undiluted but do so carefully.

Wear rubber gloves and goggles to protect your skin and eyes because this strong product can burn sensitive tissues.

To sterilize tools and equipment, you can either dip them into the solution or spray it on and wipe it off with a clean, damp cloth.

The 6-9% solution effectively kills fungi, viruses, and bacteria.

In a stronger solution (10%), it can kill mold spores and is useful for removing and preventing mold and mildew on hard surfaces (e.g., greenhouse walls). If you use a very strong solution, you must exercise extreme caution.

10. Kill Weeds

You can use very strong H2O2 (10% solution) full strength to kill weeds and moss. Pour it directly into pavement cracks in the late evening or early morning for best results. It will work best without direct sunshine.

When using this treatment, you must be very careful. Wear protective gear and avoid letting the solution come in contact with plants that you want to keep. If you come in contact with this strong product, wash thoroughly and immediately with cold, running water.

Using Hydrogen Peroxide Saves Money & The Environment

Despite the need for safety precautions, H2O2 is an environmentally friendly product. Unlike chemical fertilizers, pesticides, and fungicides, it breaks down to become water once its work is done.

You don’t have to worry about it lingering in the environment to poison the water table or kill off beneficial insects because it simply does not do those things.

A hand holding a watering can mixed with hydrogen peroxide, a natural and effective way to water and care for plants.Pin

It is also a remarkably versatile and thrifty addition to your garden arsenal. With just a couple of simple recipes, you can create gentle yet effective solutions to almost any gardening challenge.

 If you’re looking to include hydrogen peroxide in your plant care routine, use the correct potting medium.

Remember, it only takes a very small amount of H2O2 to benefit your plants and potting mix. Begin with a very weak solution of 3% peroxide.

You will probably attain perfectly satisfactory results. If not, increase the strength of your solution in increments and proceed with caution.

You may never need to use the more concentrated strengths of commercial-grade peroxide, but if you do, be sure to treat them with caution and respect. Handle them wisely to avoid injury.

Sources: 1 | 2

Recommended Reading

JOIN Our FREE Plant Care Newsletter 

By entering your email address you agree to receive a daily email newsletter from Plant Care Today. We'll respect your privacy and unsubscribe at any time.