Doubt you even need to try the peroxide. For one thing what are the "centipede type things" you have? Size, color, damage if any? And when it comes to fungus gnats, pull back on how you water. The simplest thing to do is to allow the soil surface to dry. But to get a running start on stopping the gnat's life cycle, use Bacillus thuringiensis israelensis (either Mosquito Dunks or the granular form) in the water you give to your plants. Realize that it takes several weeks to stop the life cycle. And those "unknown yellow round clusters of eggs" may well be Osmocote, a slow-release fertilizer.

Interesting. I have several plants that seem to be growing OK except that they seem to be experiencing Damping Off Fungus as I have to prop them up. They also seem almost wilted looking and some are a little yellowish looking but otherwise they seem to be growing well. I hope watering with a peroxide solution will help out...it seems to address the problems I am experiencing any way. I am not worried about getting the 30% stuff since I a gallon of solution will go a long way for me and one pint bottle of the 3% solution should make a couple gallons of the mixture for sick/fungusy plants according to the mixing directions link posted earlier. I wonder if maybe I shouldn't do what was suggested earlier and treat some of the plants and not the others to see what difference it makes. Pepperpikker

Hydrogen Peroxide is also corrosive. Issue with H2O2 is how quickly it breaks down. Once a bottle is opened and some of it is used, even if kept in the dark it will continue to break down (albeit more slowly). Therefore, by a small bottle and use it all within a short period of time. The issue with degree of sterility depends upon just what one is trying to prevent. For fungi and bacteria, simpler, less thorough methods are typically fine. However, with viruses more complete methods may be necessary. With orchids, the main concern is the transmissions of certain plant viruses. Several of these pathogens would not be affected by alcohol or the flame from a butane/alcohol flame. (The latter don't get hot enough.) I typically use disposable razors. They're cheap. Afterwards, I dry them off and toss them in a tin which goes in the oven. Next time I bake, they get "cooked".

You do not need to go to that much disruption to the plant. Just mix 1 part 3% hydrogen peroxide to 4 parts water and water the plant soil thoroughly (wait until the plant needs water again before you do so) so that the runs freely out of the drainage holes. The HP solution will kill any gnat larvae in the soil wherever it is located.