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

Well, i don't know if it helps seedlings break through the seed coat, but I do know that soaking seeds in a 3% solution of hydrogen peroxide for 10-30 minutes, followed by at least 10 rinses in clean water will kill any pathogen growing on the outside of the seed. Germination appears increase after this sterilization because some seeds get attacked by pests as soon as germination begins and the embryo is destroyed before it even emerges from the soil. This is routinely done in plant research laboratories to prevent powdery mildew, mold etc. It also prevents damping off. You can also use a 3% solution of bleach, as long as the hypochlorite level is low: javex is an excellent brand. The cheaper bleaches are not as pure and won't have the same effect. As for the hydrogen peroxide, I'd recommend using a food grade solution. As for a 'biological' explaination, hydrogen peroxide is a plant signalling molecule (like ethylene) used by the plant to mediate pathogen and environmental stress responses. It also *MAY* help in root development. I've heard of some people actually watering or spraying plants with low doses of hydrogen peroxide to help plants overcome pathogen attack, or make them hardier if a pathogen make its way into the garden. Personally, I don't like spraying my plants with too many chemicals, and if you do have a diseased plant, it is better to sacrifice it before it infects everything else. Plus, not much is known about hydrogen peroxide plant signalling yet, the hydrogen peroxide may stop pathogen attack, but what else is it telling your confused plant to do?

Hi Growitnow, I sow seeds indoors and I wintersow. I haven't used any peroxide on my WS seeds, however I have recently learned a great deal about using it on the seeds indoors. I had some bad damping off. I mixed 3% hydr. peroxide with water in a 1:10 ratio. I sprayed the surface of the soil and the mold was gone in a matter of hours. I also noticed that the seedlings grew taller and greener over the course of that night. I believe it was from the extra oxygen. I have since then cut the solution to 1:20 and I spray all my indoor trays with it every 2 or 3 days. I haven't had any problems. Some people water with it but I don't think that's necessary. HTH.

Guess I'll just have to drag myself to Houston next year for the annual PSA sale. I think it's the second weekend in June. My HD and Lowe's finally brought some plumies in around late August but they were a pretty sad bunch. Looked either unhealthy or like center-cut rejects. None of them with any indication of their color, much less a name. As for the ongoing seedling experiment, I just checked my second seed batch that was NOT treated with H2O2 and found one rotted away, with a powdery brownish growth on it, and another with the same powder. Don't know if this is a mold that's contaminated them all, but I misted with a H2O2 solution and will hopefully not lose any more. The mold may be due to the seeds being less than fresh (the two moldy ones came from India, I think, or maybe Thailand); they did look much darker than all the others. Anyway, from my first batch of three weeks ago (already at 1-3" tall and all developing true leaves), one Chompoo Wang has distinctly red first true leaves coming up while the other two CW seedlings are normal green. Even at only about 1mm long they are really red. Very cool!