Mixing Charts for Gardening
with Hydrogen Peroxide

If you want to start gardening with hydrogen peroxide, you need to know how much peroxide to use. Here are charts to tell you how much.

Learn about using hydrogen peroxide in the garden.

Learn different ways to mix and apply hydrogen peroxide for use in gardening.

To water or mist plants, to soak seeds, to add to water used to wash sprouts:

TO THIS AMOUNT OF WATER ADD THIS AMOUNT OF 3% HYDROGEN PEROXIDE --OR-- ADD THIS AMOUNT OF 35% HYDROGEN PEROXIDE
1 cup 1 and 1/2 teaspoons 7 to 10 drops
1 quart 2 tablespoons 1/2 teaspoon
1 gallon 1/2 cup 2 teaspoons
5 gallons 2 and 1/2 cups 3 tablespoons plus 1 teaspoon
10 gallons 5 cups 6 tablespoons plus 2 teaspoons
20 gallons 10 cups 3/4 cup plus 1 tablespoon plus 1 teaspoon
bathtub (aprox 25 to 35 gallons) * 12 to 17 cups 1 to 1.5 cups

* bathtub sizes vary. It is okay to use more water and/or less peroxide.


To spray on sick or fungusy plants:

TO THIS AMOUNT OF WATER ADD THIS AMOUNT OF 3% HYDROGEN PEROXIDE --OR-- ADD THIS AMOUNT OF 35% HYDROGEN PEROXIDE
1 cup 1 tablespoon 1/4 teaspoon
1 pint 2 tablespoons 1/2 teaspoon
1 quart 1/4 cup 1 teaspoon
1 gallon 1 cup 1 tablespoon plus 1 teaspoon
5 gallons 5 cups 6 tablespoons plus 2 teaspoons
10 gallons 10 cups 3/4 cup plus 1 tablespoons plus 1 teaspoons
20 gallons 20 cups 1 and 1/2 cups plus 2 tablespoons plus 2 teaspoons

Please be mindful to choose the correct column in the chart depending on whether you are using 3% hydrogen peroxide or 35% hydrogen peroxide!!


As you may notice, the amount of peroxide in the chart for sick and fungusy plants is twice as much as in the first chart. I have heard of people using stronger solutions, but more is NOT always better. So be careful, and when in doubt, stay safe. You can always apply more another day. If you decide to use a bit more, please make it only a little bit more, don't get carried away. Gardening with hydrogen peroxide is great, but too much can harm your plants.

Be Careful: When Gardening with Hydrogen Peroxide, the Concentration Matters!

10% hydrogen peroxide is recommended as a weed killer -- in other words it will kill your plants at that concentration....

As with all things H202, the amount and concentration of peroxide you use matters. The right amount will benefit your plants, and too much will harm them or even kill them.

There's some room for variation, but there's also some risk.

Where did these recommended amounts come from?

I did not make up the amounts in the charts, I got basic proportions from printed books and newsletters. (Think back, if you are old enough, to a time long before the internet. Imagine homemade booklets about hydrogen peroxide, typed on a typewriter!)

What are some other dilution recommendations for gardening with hydrogen peroxide?

There are a variety of published recommendations, and, as you might guess, they do NOT all agree.  Still, I think it's good to start with an amount that has some history of use, so that's what I've done. But also remember that such recommendations are based on the experiences of people who simply tried things out, and looked at the results.

As an example of the variations, I just looked at a few pages about peroxide in gardening. I found one that said to mix 3% hydrogen peroxide with water to feed to plants, but did not say how much to use!  I found another that recommends 1 teaspoon of 3% H2O2 in a gallon of water (which is about 1/8th as much as in the first chart, above!) I also found a commercial garden product that recommends using a few drops of 35% hydrogen peroxide per gallon, and using this for every watering (also drastically less than what is listed in the first chart, above).

Lots of gardening and hydroponics websites have a link to this page in order to provide the dilution charts, above, for gardening.  Which is great -- yet I'm reluctant to have this become the authoritative source on how much to use!  I honestly doubt that there is such a thing as a single answer.  There could an accepted answer, or a range that is safe, but I doubt that there is a single best answer.

How often to apply H2O2 to plants?

You may wonder how often you should use peroxide on your plants. I don't have an answer to that.  If you are treating a fungus or mold or an ill plant, you would want to use it until the problem clears up or the plant looks healthy again. But you need not use it for every watering! For general purpose use gardening, I have not really seen much in the way of recommendations.  I personally use it only once in a while. I've seen really good effects using peroxide to water young plants and with soaking seeds, giving the seeds or plants an early boost in growth.

Return from Mixing charts for gardening with hydrogen peroxide to home page....

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