I've heard it can help with root rot and the such. H2O2 will oxidize anything, which in the case of most tissues (human, plant, whatever) means killing it. That's why it's not recommended to use H2O2 on wounds anymore. Sure, it kills the bad stuff, but also kills all the good tissue, and turns out soap and water does just as well, or iodine. H2O2 will kill your plants, especially seedings I'd think. But, it also does what you've heard it does. Use very sparingly, but I don't know how to tell you to do that. It would depend on the soil type, the plant, etc, and I'd probably still be guessing. You might start will a very very small amount in a gallon of water. Make sure you know the concentration of the H2O2 before trying to mix it; obviously, that will effect the final concentration. I've heard reports about increased growth and limiting root rot and disease. I've also heard about dead plants, and significant reduction in growth and production. Unfortunately, I've never tried it myself. I think there are safer ways to do what you want to do here. Use the correct soil/mix and watering requirements for the container and the plant. I doubt H2O2 is any magic formula, or we'd know more about it.

H2O2 has an extra O atom (compared to H2O) in an unstable arrangement. It's the extra atom that makes it useful in horticultural applications. Generally, we're not concerned with aerobic forms of bacteria normally occurring in container media or on roots. Since H2O2 is an unstable molecule, it breaks down easily. When it does, a single O- atom and a molecule of water is released. This O- atom is extremely reactive and will quickly attach itself to either another O- atom forming stable O2, or attack the nearest organic molecule.

Reduced O levels and high temperatures encourage both anaerobic bacteria and fungi. Many disease causing organisms and spores are killed by O, and the free O- H2O2 releases is very effective at this. Additionally, when plants growing in water-retentive media are treated with H2O2 it will break down and release O into the area around the roots. This helps stop the O from being depleted in the water filled air soil air spaces until air can get back into them. High O levels at the roots will encourage rapid healthy root growth and discourage unwanted bacteria/fungi.

I know H2O2 comes in several different strengths, the most common of which are 3% and 35% solutions. Least expensive is the 35% product (what I use) which you dilute (to an approximate 3% solution) by mixing 1:11 with water. I have used the 3% solution at 1-½ to 2 tbsp per gallon as a cutting dip/soak, and have mixed it into irrigation water for plants in extremely water retentive soils at up to 3 tbsp per gallon, both with good results and nothing adverse apparent.

H2O2 in high concentration is a powerful oxidant and quickly oxidizes almost anything it contacts, so be careful with it if you use it. A solution that is too strong can destroy any organic molecule it contacts.

IÂve seen this chart posted several times as suggested strength solutions for use in watering plants. You may wish to start at a lower concentration , such as IÂve used, and experiment.

TO THIS AMOUNT OF WATER ADD THIS AMOUNT OF 3% HYDROGEN PEROXIDE --OR-- ADD THIS AMOUNT OF 35% HYDROGEN PEROXIDE

1 cup, add 1-1/2 teaspoons  35% - 7 to 10 drops
1 quart, add 2 tablespoons  35% - 1/2 teaspoon
1 gallon, add 1/2 cup  35% - 2 teaspoons
5 gallons, add 2-1/2 cups  35% - 3 tablespoons plus 1 teaspoon
10 gallons, add 5 cups  35% - 6 tablespoons plus 2 teaspoons
20 gallons, add 10 cups  35% - 3/4 cup plus 1 tablespoon plus 1 teaspoon

Al

Does this stuff have a shelf life?

Damon

We have a bottle of 3% at the shop for cleaning wounds. It's been there for the whole 21 years I've been there and it still foams nicely on cuts. So imo, shelf life is > 21 years. :)

I have had some at the house quickly go "flat" though from forgetting to put the cap back on the bottle.

PS I treated some hot peppers plants and a couple sickly chayote squash plants just yesterday with diluted 3%. They're still alive! One reason I started using it is to help break down the chlorine in the city water now that I'm out of rain water.

I keep the 35% containers in the deep freeze. They don't freeze, btw - not even at 0* F. Not sure you could do this with the 3% solutions, though.

Al