Hydrogen Peroxide

hydrogen peroxide molecule

Hydrogen peroxide, H2O2, is a very interesting substance.  It differs from water by only one simple oxygen atom, but what a difference that one little atom makes.  Water is a benign substance that makes life possible on this planet.  Many believe that water was the catalyst for life.

Add that one little oxygen atom and things become quite different.

One Extra Oxygen Atom

Hydrogen Peroxide, in its pure state, is a slightly viscous pale blue liquid.  It is very reactive and used as an oxidizing agent in rocket fuel.  It is, in fact, quite unstable and can be explosive if handled improperly.  What surprises most people is that in one of several forms, hydrogen peroxide is found in the human body and is necessary for the body to function efficiently.

When diluted to a solution of 3%, hydrogen peroxide becomes quite stable and very useful.   It is a mild bleaching agent and a disinfectant.  Every child has been fascinated by the reaction as H2O2 is poured on a cut, and the solution fizzes about the open wound. Often used as a sterilant for surgical instruments, many environmentalists see H2O2 as a much better alternative to chlorine bleach because it degrades rapidly to form oxygen and water unlike Chlorine bleach with leaves a residue of chlorine.

Hydrogen Peroxide 3%

What most people don’t realize is that this rapid decomposition of H2O2 is useful in horticultural applications.   When applied to hard-packed soil, it can act on the soil to make it fluffier.   The addition of the water and extra oxygen molecule in the soil stimulates growth in the microbiome, further enhancing the soil.  Many garden pests are also susceptible to the effects of H2O2 being either repelled by it or killed outright.

There are several ways to use H2O2 in the garden and landscape.   Listed below are some of them with the mixing and application instructions.

3% H2O2 (Grocery store products)

  • Skin – disinfectant   use full strength
  • Water – kills algae in rain barrels, birdbaths, and animal water troughs. Mix 8oz.. (1/2 pint per 50 gallons of water
  • Fish ponds –  controls string algae and others.  Mix ½ gallons per 1000 gallons of water. 
  • Aquariums – in a 16-gallon tank mix 0.1 oz
  • Hard Surface – use full strength as a disinfectant
  • Earwax – Use full strength to soften and free wax
  • Washing machine and dishwasher – use 4oz per load to disinfect and control scale
  • Plants – rose rosette and others.  Mix Garrett Juice but replace 16 ounces of the water with H2O2
  • Soil Improvement – to improve soil flocculation (fluffiness), apply 16 – 32 ounces per gallon of water.   One gallon of the mix should treat approximately 1000 sq feet.

35% H2O2

  • Swimming Pools – controls mustard algae.  Use one gallon per 5000 gallons of pool water
  • Koi Ponds – use 1 cup per 1000 gallons of water
  • Weed Killing – Spray weeds with 10% H2O2  (mixing formula shown below)
  • Disease Control – Mix to 1ounce per gallon of water and spray plants
  • Soil Treatment – Mix at a rate of 2 ounces per gallon of water.  Apply one gallon of mix to app 1000 sqft

Use 1 ounce of 35% H2O2 per 11 ounces of water to make a 3% H2O2 solution.

Conversion Factors

  • 1 part 35% H2O2 to 11 parts water to yield a 3% solution
  • 1 and ¼ cups 35% H2O2 to 14 and ¾ cups water = 1 gallon of 3% H2O2

Ninety-two ounces of water  37 ounces of 35% H2O2 = 128 ounces (1 gallon) of 10% H2O2

One hundred twenty-two ounces of water + 6 ounces of 35%  H2O2 = 1 gallon of 1.6% H2O2


Follow all label instructions on any H2O2 product.  The concentrated forms of H2O2 can burn skin and injure the eyes.  Handle these products with great care.  Use the proper protective gear whenever handling caustic chemicals.  NEVER DRINK H2O2 IN ANY CONCENTRATION!

Links and Resources

For more information about organic gardening, lifestyles, and living, visit our website at West Texas Organic Gardening

If you found the information here helpful, you might also find these articles on our website of interest.

The Vinegar Question

Assessing Soil Health

Bacillus Thuringiensis (BT)

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