More on peroxide, thanks to my cousin Damon:

"If any substance is interesting, it's hydrogen peroxide. Hydrogen peroxide should really be called hydrogen dioxide. Its chemical formula is H2O2. It contains one more atom of oxygen than does water (H20).

By now everyone's aware of the ozone layer that surrounds the earth. Ozone consists of three atoms of oxygen (03). This protective layer of ozone is created when ultraviolet light from the sun splits an atmospheric oxygen molecule (02) into two single, unstable oxygen atoms. These single molecules combine with others to form ozone (03). Ozone isn't very stable. In fact, it will quickly give up that extra atom of oxygen to falling rainwater to form hydrogen peroxide (H202). (Bear with me: all this chemistry mumbo jumbo I'm going through actually will help you understand the importance of hydrogen peroxide.)

Helps Plants
It is this hydrogen peroxide in rainwater that makes it so much more effective than tap water when given to plants. With the increased levels of atmospheric pollution, however, greater amounts of H202 react with air-borne toxins and never reach the ground. To compensate for this, many farmers have been increasing crop yields by spraying them with diluted hydrogen peroxide (5 to 16 ounces of 35% mixed with 20 gallons of water per acre). You can achieve the same beneficial effect with your house plants by adding 1 ounce of 3% hydrogen peroxide (or 16 drops of 35% solution) to every quart of water you give your plants. (It can also be made into an excellent safe insecticide. Simply spray your plants with 8 ounces of 3% peroxide mixed with 8 ounces of white sugar and one gallon of water.)"

To read the entire article, see The Many Benefits of Hydrogen Peroxide by Dr. David G. Williams.