Not quoting, but if memory serves me right, H202 is bad in "organics", or any medium where you are using beneficial bacteria (hopefully all mediums). h2o2 is just h20 with an extra unstable oxygen molecule that attaches itself to bacteria and fungi, essentially killing it. If your roots are healthy, there should be bacteria and fungi that are NECESSARY for maintaining root health. If you kill them all off, your plant will suffer for it.

Plus, if you are using organics (especially TLO), you can literally wipe out everything you were trying to establish in your growing media. Organics is by all accounts "living" soil.