13 uses for peroxide in the garden (and on houseplants!)

Hydrogen peroxide has long been a bathroom staple, known for its cleansing and disinfecting properties. Those same  properties though, are the reason why peroxide has so many amazing uses in the garden. Not only can hydrogen peroxide be used to clean and disinfect tools, but it can also destroy fungus and even pests like aphids.

Hydrogen peroxide is very similar to water except it has one more oxygen atom. So while the H20 we drink has 2 hydrogen and 1 oxygen, hydrogen peroxide is H2O2 which is 2 hydrogen 2 peroxide. (I promise this ends the science lesson for today!) 

When you add that extra oxygen atom to the plant, it can do a lot of really great things....and one horrible one!

Hydrogen peroxide comes in various concentrations but the most common one is 3%. That's the one in the brown bottle at the grocery or drug store. It'll say on the back  of the bottle though, so flip it around just to make sure. 

3% hydrogen peroxide is the strength I use, and I wanted to point this out because that is what I have experimented with and when I mention how I mix the peroxide to use it, it's with the 3% strength. 

If you happen to have a different strength of peroxide, then you'll have to adjust for the difference or the solution will be too strong and can cause problems.

How to use peroxide in the garden

1) Faster seed germination: soaking seeds in a solution of 1 tsp of 3% hydrogen peroxide to 1 cup of water for about 30 minutes before planting can help the seed coating to soften and germinate faster. Rinse before planting.

2) Sanitizing seeds: Soaking seeds before planting also destroys any bacteria that might be on the seed surface. Especially helpful if you received seeds through an exchange or are at all unsure what kind of conditions they came from. Rinse the seeds well before planting.

3) Mold and mildew: By applying the hydrogen peroxide solution to soils with bacteria, mold or spraying on powdery mildew it can combat these common garden ailments. When dealing with a particularly stubborn case I had to mix it twice as strong, but it worked without harming the plants. Reapply after rain. 

4) Fertilizer: when properly diluted, peroxide provides that extra oxygen atom to plants at the root making it an excellent fertilizer. Mix 1 tsp of peroxide per cup of water and water plant at the roots.

5) Soil pests: that same watering solution we used above can help fight off soil pests like grubs, gnat larvae and root maggots.

6) Leaf pest spray: using a solution of 1 Tbsp peroxide to 1 cup of water, spray the infected plants foliage to fight bacteria, fungus and pest infestations. This can help with aphids and spider mites.

7) Root rot: Root rot begins when plants are overwatered and left standing in their wet soil for too long. Improper drainage can cause this when the wet soil blocks the roots from absorbing oxygen. By watering with a solution of hydrogen peroxide and water (yes, even while wet) It allows the roots access to the oxygen it needs. 

Hydrogen peroxides spontaneous decomposition releases oxygen that enhances a plant's root development and helps to treat root rot (cellular root death due to lack of oxygen) and a variety of other pests. wiki

8) Rooting agent: when rooting cuttings, water them with the hydrogen peroxide water solution mentioned above. The extra oxygen will help give your new cutting a great start.

9) Prevent infections when trimming bushes and trees by spraying the cut areas with the water and hydrogen peroxide solution to kill bacteria.

10) Weed killer: While using a watered down hydrogen peroxide solution can give your plants a nice boost, spraying full strength hydrogen peroxide directly on plants can kill them. This comes in handy with pesky weeds, just be careful of overspray.

Peroxide for cleaning in the garden

11) Water treatment: I've read that adding hydrogen peroxide to water before watering your garden will remove chlorine from public water sources (I didn't try this one though since I have a well)

12) Repotting: Spray the inside of old pots with hydrogen peroxide before using them for new plants to kill bacteria and sanitize the surface. Rinse well before using.

13) Clean garden tools: To clean and disinfect garden tools (especially after using them around infected plants) spray full strength hydrogen peroxide onto your garden tools and allow to set for a few minutes then rinse. 


One of my favorite things about using hydrogen peroxide in my garden is that I already have it on hand, so I'm not stockpiling additional chemicals. Plus, it's super cheap as far as garden treatments go and I don't need to go to a specialty garden center to purchase it. That's a win-win!

~L

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