maybe for hydro, but for soil i would use air stone and air pump, let it bubble for say 6-8 hours and water your plants with that, but i have never used it... i think it will clean the slim and gung off the plants roots....
it is just a way of getting more oxegin into your water...its just an aqarium air pump with a air stone or sand stone on the end of air hose, stick hose in water and pump air through water for awhile...the stone makes tiney little air bubbles in the water...
the H2O2 you would want to use is a 35% food-grade concentration... 1-2ml per gal.
it is not recommended you add this solution to your soil grows as it will kill off any organic or biological goodies growing in the soil that are BENEFICIAL to your grow...ie... it "sterilizes" the soil - this is my understanding... if someone else here can further comment....
as I stated before... I wouldn't recommend giving H2O2 to your soil babies.
you are better off to get an aquarium air pump and air stone and use that to oxygenate your water, like gettinggray suggested Hydrogen peroxide is more of a hydroponics setup tool.