Geranium Guide

Four Uses of Hydrogen Peroxide for Geranium Plant Health

Hydrogen peroxide, also known as H2O2 is mostly known for its properties in cleaning and disinfecting wounds, but not many people know about the use of hydrogen peroxide for geranium health. It’s important to consider though that the hydrogen peroxide must be diluted before applying, as hydrogen peroxide straight from the bottle will cause burns to geraniums plants. What’s the hydrogen peroxide to water ratio for plants?

Generally, the dosage is 1 to  2 teaspoons and a half of 3 percent hydrogen peroxide diluted in one gallon of water. It’s best to start at lower concentrations and then increase gradually. Three percent hydrogen peroxide is commonly found in stores in the familiar brown bottle meant to block light. It should be pure H2O2 without any chemical additives. For safety, it’s a good idea to to test its use on limited plants prior to spraying all the rest.

1) Hydrogen Peroxide for Geranium Seedsgeranium-seeds

Are you planning to plant some geranium seeds? Then this little tip may come at the right time. Soaking geranium seeds in hydrogen peroxide can be helpful in several ways. First off, the hydrogen peroxide will kill any fungal spores or pathogens present on the seeds. Secondly, it will soften the seeds which will help them germinate faster. Both these actions can help increase the germination rate which is something everybody wants.

After all, it’s saddening when several seeds fail to germinate or seeing several seedlings not making it. To reap these benefits, simply soak the seeds in three percent hydrogen peroxide for about 30 minutes. Then rinse with water and plant as usual.

2) Hydrogen Peroxide for Geranium Cuttings hydrogen-peroxide-geranium

Adding hydrogen peroxide to the water meant to be used to water geranium cuttings can be helpful. The presence of diluted hydrogen peroxide may help the plants root more firmly. Why is that?

H20 is the normal formulation of water, but hydrogen peroxide happens to have an extra atom, which is why it’s known as H202. It’s ultimately this extra atom that comes handy for many horticultural applications.

Hydrogen peroxide therefore can help roots, and at the same time, can help prevent future problems with unwanted disease-causing bacteria and fungi.


Hydrogen Peroxide for Geraniums Root Rotroot-rot-geranium

As mentioned several times, geraniums hate to have their “feet wet” and excessive watering and moisture, can predispose the geranium plants to root rot.  When a geranium plant is over watered, the excess water fills the air space in the soil and the plant develops a troublesome shortage of oxygen at the roots. The roots therefore literally suffocate and may start rotting at the roots.

Watering the plant thoroughly with some 3 percent hydrogen peroxide diluted in water, can provide extra oxygen that may help the roots survive.

The addition of a product with rooting hormone dissolved in it may turn extra helpful. The hydrogen peroxide watering can be repeated again, but only when the first couple of inches of soil are dry and it’s time to water again.

Hydrogen Peroxide for Fungal Gnats gnat by Python (Peter Rühr) - Own work

Fungal gnats are pesky bugs who like to live in areas where there is high humidity. These gnats like to lay their eggs in the first couple of inches of soil and soon larvae will hatch and start feeding on the roots of seedlings and small plants. Getting rid of the pesky gnats can be quite a hassle. Killing the adults won’t do much unless you kill them all considering that one single gnat can produce over 200 eggs!

Using a ratio of 1 part hydrogen peroxide to 4 parts water can help kill the larvae from the soil, keeping the population under control. You should water your geraniums with this solution until the gnats are gone, watering with it as you normally would when the first couple of inches of soil are dry.



  • Thirty Five Reasons to Have Hydrogen Peroxide in Your Homes, By J.D. Rockefeller

Photo Credit:

Wikipedia Fungus gnat, Python (Peter Rühr)Own work CCBY3.0