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Hydrogen Peroxide at home and in the Garden Answered

Although the topic is quite old for some of us and mostly because I am too lazy today to make an Instructable: Hydrogen Peroxide !

Back in the day Hydrogen Peroxide was mainly known for the ability to bleech your hair, later it replaced chlorine based products for the preparation of paper and organic fibres.
For me it is a good opportunity to go back in time and to pull out some of the remedies my grandparents already used.
Who knows, there might be something that helps you or you might know other good uses that I failed to mention here, so feel free to comment.

First off: What actually is hydrogen peroxide?
We could check Wikipedia but I think it is enough to say that it basically water with an added oxgen mulecule which turn the stuff into a quite powerfull oxidizer.
When hydrogen peroxide reacts the added oxygen is released and the normal water remains.

Precausions and health risks.
In the normal supermarket form hydrogen peroxide comes at a strenght of just 3%.
This is just enough for wound treatment or cleaning off a fresh and small stain.
The stuff you can buy at your hair dresser comes in concentrations of 5-15%, above that it is of little use to them.
Pool grade peroxide however can come as high as 50%.
It often requires a permit of at least leaving a copy of your drivers license to buy such high concentration but well worth it price wise.
The downside of anything above 5% is a risk for your skin, eyes and airways.
So when handling hydrogen peroxide you should waer long sleeve rubber gloves, safety or better swimming goggles and make sure that you don't create vapour by spraying it against the wind direction.
Having water at hand to dilute and spillage on your skin is always good.

What happens to me if things go wrong?
Well, if handled correctly nothing should go wrong but of cause the worst would be eye contact.
Getting concentrated hydrogen peroxide in your eyes means extreme pain and even with rinsing it out asap eye damage is more than just possible.
Again: wear proper eye protection and if spraying use a filter mask, the paper type is enough!!!
Nothing immediate happens on sking contact but a few minutes after contact the skin will turn slightly brown or goes white.
This is caused by the oxygen release into your skin cells, if washed off quickly after noticing the discoloration will fade after a few hours.
Prolonged exposure of the skin can cause skin cells to fully discolor and living cells might get damaged - a burning sensation is usually the sign that you need to wash the area now ;)

Enough bad stuff said, let's see what we can do in the garden....
Fungal infection of your old roses or on your fruit trees?
Sometimes the weather does not like our plants and by the time we discover a fungal infestation it is usually pruning time.
There are commercial producta available that work quite well but especially the copper based ones tend to do more harm than good in th long run.
An alternative is a solution of 10-20% hydrogen peroxide.
Spray generously over all affected parts of the plant, leaves, twigs, stem and all.
Make sure everything is properly wet!
In some cases the fungus can act as a water replellent and it seems impossible to get any of the solution to wet these areas - a drop of dish washing liquid into the bottle will fix this!
Watever runs off can be left as it only helps to get oxygen into the soil but of course you should not soak the area...
Leave it on for about an hour, around 20 minutes if it quite warm.
Rinse all off with clear water and repeat every 2 days for 5 treatments all up.
After this time wait 2 or 3 weeks and check if the fungus still gows in some hard to reach areas.
If so then repeat the treatment there until satisfied but wait another 2 weeks every 5 single treatments.
In some areas of the world certain types of fungus on roses are refered to as "rust".
Moved into a new home and the garden beds smell really bad?
The last house I moved into had a previous occupant with a big dog but no time to clean after his pet.
The garden beds looked dead and I mean so dead that I could not even find weeds in them.
And the smell was a distinct mix of old dog poo with lots of fresh cat poo mixed in it - the perfect outdoor pet toilet :(
Trying to dig it all under made me recover that the top soil was more §$&*# than soil.
I had to get rid of the bacteria of all the poo and somehow neutralize a lot of the unwanted "nutrients".
The solution was to first loosen all the soil as deep as I could go.
Then I added rice straw (but anything straw like or dry grass will do) to mix it through.
At this stage I wished I had a gas mask LOL
All up the contaminated garden beds covered about 20square meters.
I got a 10 liter canister of pool grade hydrogen peroxide, from this I diluted down with 20 liters of water and a few drops of dishwashing liquid to help with the soil wetting.
All was applied as evenly as I good with a watering can and then the area was covered with some tarp to try keeping as much oxygen on and in the soil as possible.
A day later the tarp was removed and all beds watered with hose to drowning point.
This watering was repeated every 3 days for 3 weeks to drive out all the excess and unwanted nutrients from the poo.
The smell was already gone except for some cat urine residue which disappeared after some rounds of watering.
Three months after the initial treatment I did some soil tests, added nutrients were required and the next season I had vegetables growing :)
Whether from seeds or seedlings, give hydrogen peroxide a try!
I use a 5% solution to soak the potting mix I use before putting my seeds in it.
Not only does it kill a few of the unwanted things that might still be in there but it adds a lot of oxygen into the soil, which gives the seeds a much better start.
For seeds I use a 5% solution as well but only leave them in for about an hour before placing them between some wet paper towels until they start germinating.
This way I can be sure all harmful bacteria and fungal spores are dead and I can use a sterile seed to keep going.
Might just be my opinion but I think the germination rate is better and seedling in comparison start growing faster and stronger.

Home uses....
As we learned before hydrogen peroxide, at least in higher concentrations is a powerful way to remove fungus.
In our bathrooms we often have the problem that the ceiling starts to develop black spots as in the colder times water condenses here and takes a long time to dry off.
If you now go to your favorite hardware store they will recommend the use of a chlorine based product, basically bleach...
And although it does the job it also means your house will stink for days and if you scrub the ceiling you will get it on your sking and stink too.
Hydrogen peroxide at 20% or higher concentrations can be sprayed onto the cleiling :)
Of course you will need good protection for this and all things color should be removed, like towels or floor mats.
By protection I mean a minimum of swimming goggles, a tyvek suit or similar to cover all exposed skin areas and at least a paper dust mask, better a filtered respirator like you use for spray painting or using insecticides.
If you have a spray bottle with an adjustable nozzle then a stream is far better than a spray mist!!
Not only is your exposure far lower but it much easier to wet the ceiling quickly.
Wet all affected areas, then leave and the room, close the door and take off all clothes you used t protect you.
The clothes can be left out to dry but double check that you had no soaked spot where your sking might have been in contact - if so rinse the skin with plenty of water!
It will take some time to work and then dry, so best to do this in the summer time or if during the colder times you need to make sure the room is porperly heated and aired out to dry!
Repeat until all black spots are gone, really bad areas will leave a permanent discoloration looking like a slight brwonish color is the ligh it right otherwise you won't see it.
Once fully dry it is best to scrape off all lose paint and then to use a acrylic based sealer before giving the ceiling a fresh coat of white.
The sealer will prevent the water to penetrate more than the paint level and if you get the fungus back on the paint it is far easier to clean ;)
Carpet cleaning....
When moving into a new rental with carpet on the floor you often are left with areas indicating the carpet might be "clean" but the underlay certainly is not.
You can fix the underlay but you certainly can make sure all harmful stuff is gone from the carpet.
Carpet cleaning machines can be hired but often much cheaper if you buy the "recommended" cleaning product with it.
Rent is usually based on a daily base and price depends on how much cleaner you need.
If you only want to desinfect the carpet which otherwise looks mostly fine than go for the smallest pack available and use it to spot clean areas you want cleaner first.
For the desinfecting part I recommend to test how high you can go with the concentration of the hydrogen peroxide before using it on a big scale - keep in mind the carpet will never be fully dry and the remaining peroxide will continue to act!
Test a 10% solution first before you go higher as you don't want to buy 30 liters or more of pool grade peroxide - just trust me on that one and only try to buy this much you do want to get into trouble a few days later!
If 10 percent solution left on the carpet does not cause any bleaching of the fabric (unwanted bleaching that is) you can try higher for spot cleaning in demanding areas.
A good spot to try the solution is under the cover or duct outlets, under these joining bars where carpet changes to tiles (if you can lift them off) or in wardrobes if the carpet goes inside.
There are two way to treat your carpet once the general cleaning is done.
a) use a garden sprayer or similar to wet the carpet
This is good for single room treatment like for the baby room but especially on thicker carpets it requires a lot of solution and can become costly.
Once wet leave for at least 30 minutes so the peroxide can do its thing, then use the machine with either the solution filled or just to dry off the carpet.
I recommend to use the peroxide solution in the machine as it allows for better penetration and it will remove more soiled solution this way.
If your catching container starts bubbling like mad it means you have a lot of §$%&#+ in the carpet and it might be best to first clean it all with the normal carpet cleaning agent before using the peroxide again - again tesing on smaller areas can help wasting the peroxide.
If you need to store prepared solutions than it is best in a cold place.
It will take several hours on an otherwise clean carpet for the peroxide to fully disappear so it best to use shoes and prevent skin contact during that time - especially if a baby crawls around ;)
We don't want to talk about it but everyone needs to clean their toilet sooner or later.
For most things in there using the toilet brush when it happens will keep things clean and healthy.
But what if someone in the house is sick or with a weak immune system?
You could use all sorts of commercial cleaners and desinfectants but a wipe with wet towel or cloth soaked in a 10% solution of hydrogen peroxide will quickly eliminate all harmfull things on your seat, lid or bowl, including the buttons to press and the door handles ;)
Just wipe and leave it wet for a minute or two then wipe again and ry - done!

Personal use
I always pack a small bottle of supermarket grade peroxide when going off road or camping trips.
Although we now have modern desinfectants that won't stink or otherwise harm you I still prefer the old stuff ;)
If you are far from civilisation than the last thing you want to need is medical attention for something that started as small as a scratch or graze....
Out in the unkown wilderness you will never know if the rockk you just crash landed on was used as a urinal by a fox the night before...
A bit of gravel left in your skin might contain harmful bacteria...
A cut with your own knife?? - What did you all cut since the last proper cleaning of the blade?
You see where I am going here, a small thing might turn into something really nasty a day or two later.
If you clean a freash and minor wound properly and then rinsie it with hydrogen perodixe most if not all harmful leftovers will be killed by the releasing oxygen.
Of course this pretty much useless on bleeding wounds or where it is obvious that you won't be able to remove all debris from the wound - here it means you trip is still over in favour for proper medical treatment.
The thing is that hydrogen peroxide was basically abandoned for all wound treatment once the modern "cleaning aids" became available as the peroxide will not only attack harmful things but also living tissue.
The claims goes as far as causing bad scar tissue, damage to blood vessels and even "burning" of the tissue.
One big problem I have with all these claims is that they were never really mentioned until the new meds came out.
IMHO exposure time and how you use it it the key - common sense if you ask me.
Noone should ever soak a wound in peroxide, if it is that big that you need to soak it you need medical attention anyway.
And as said you should rinse the wound, that means all remaining liquid should be allowed to flow off - this will only leave a minor amount of peroxide in the wound and the exposure time will end with once all oxygen is released.
For minor wounds I only use a paper tissue or cotton bud soaked in peroxide and wipe the wound....
Smelly feet?
Ok, maybe not the best way to start a conversation but we all know what sneakers do to our feet in the summer...
Insoles with copper and activated carbon will help a lot and at least "cure" your sneakers while they are off your feet and have time to dry.
But the smell is actually cause by bacteria growing from everywherey in your sneaker to your sking, actuall starting at your sking...
If you wear your sneakers for long periods of time time or even whenever possible and also suffer from a bad smell hydrogen peroxide might be able to help you.
Most sneakers will tolerate a machine wash and should come out germ free, if that is no option pack them in a sealed back and leaven them in the freezer over night - this will kill all bacteria and remove the smell.
Now to break the endless cycle you need to remove the bacteria from inside your skin.
So daily sock changes, freezing shoes and washing feet is a must!
Your feet will really benefit from a foot bath in a 5% solution of hydrogen peroxide.
To keep costs at a minimum use a container that is just the right size for your feet and prepare the solution from pool grade peroxide.
I an ideal case you should not need more than 2 liters but all used product can be stored cool and re-used the next day, after that you need to make a new batch.
Keep your feet submerged for at least 10 minutes.
This will allow a deep penetration of the skin but might result in some white spots that will disappear after a few hours.
Consenquent foot baths can be reduced to 5 minutes.
After about a week you should notice that wearing your sneakes no longer causes and bad smell and you can stop the treatment.
Freezing the sneakers over night, dialy (or more) sock changes and daily, proper cleaning of your feet should prevent any further bad smells :)
Bleaching your hair
Althoug it was done for many years I really can't recommend using hydron peroxide for this purpose!
Any concentration strong enough to have a proper effect in a reasonable time will at least cuase skin irritation.
Back in the days they said your burning scalp is what you need to endure to get blonde hair :(
And as said already you really don't want to get that stuff into your eyes...

General uses
If you have a fruit based stain then cahnces are hydrogen peroxide will remove it, especially if fresh.
Even at supermarket concentration repeated application and proper drying off with a paper towel or similar will remove even red wine or beetroot stains.
On you skin blood is easy removed with cold water, same on other surfaces but washing off is no option a wet cloth or cotton piece will work fine.
Hydrogen peroxide is good if things need to go fst or if the surface is porous, here the releasing oxigen will drive out the blood with the bubbles.
Fish tanks...
If you love your tank then you really hate to medicate or even worse have a bad algea infestion, especially the stuff of the black kind.
A change to activated carbon filter material is always recommended after a medical treatment to remove all leftovers from the system.
However, certain medication simply won't be affected by a carbon filter and stay in the system until fully used or broken down otherwise.
Especially in bigger tanks a partial water change is often out of the question as it would cause too much additional stress to the fish and plants.
Hydrogen peroxide can help to break down most if not all remains of the used medication while at the same time adding more oxygen to the water.
To be sensitive and safe in all enviroments I recomment to calculate the concentration based on the volume of your tank and to add the required amount of peroxide very slowly into the outgoing water stream from your pump.
By slowly I mean in terms of a slow drip if using solutions over 10% to be added to the tank.
If in doubt remove a suitable amount of tank water into a bucket and add the concentrated peroxide to reach the final tank limit.
I strongly recommend to stay below 2% in favour over additional treatments a few days later if required.
That means the diluted solution you add should be entered into the tank slowly if in doubt add a glass full every few minutes.
For the treatment of the dreaded black algea you do the same 2% solution but be prepared that it will take several treatment until you see them die off.
If you can then it is best relocate the fish for a few days so you can use a stronger solution of 5-8% just with the plants left in the tank.
When transporting fish in a bag it can pay off to add a little bit of 3% peroxide to the bag to give additional oxygen for transport.
I do this maually for every fish I buy from a store so I can be sure all fungus and bacteris is killed of before I introduce it to my tank.
Really helps to prevent loosing a lot of fish just because you added one or two more to your tank ;)
For the normal sized transport bags I use a good shot glass full of 3% peroxide in case you wondered.
Fridge and freezer
Be it after long use or because you bought one second hand - once empty and warm some of our colling gadget just smell bad.
A good clean with a hot water and your favourite cleaning agent is a good start, no need for aggressive stuff ;)
If clean but still smelly, like after a power failure with fish in it you might want to go one step further.
Best option is to use a spray bottle and a peroxide solution of at least 15% here.
Use proper protection as mentioned above and spray all surface with the solution until soaked.
What you can take out you take you take out, clean properly and then wipe or brush with the same peroxide solution.
Bare aluminium should be handled with caution as in some cases it can oxidise badly, leaving a white and not removable crust behind.
Here it is best to wipe and then wipe again with a cloth soaked in clear water to limit exposure time.
No need to dry out - wipe out and check if it still smells, if so repeat and wiped off all areas as good as you can with a solution soaked cloth.
Once the smell is gone dry out and enjoy smell free use from now on :)
Fruit and vegetables
Unless you know exactly what happened to it you might want to clean your vegies and fruits properly before using them.
Pesticides, herbicites, fungicites....
Not mention normal fungus and bacteria on the product....
On a commercial base hydron peroxide baths are often used to clean products for sensible people, hospital use or long term storage.
For a personal use this only makes sense if you have free and unlimited access to the peroxide.
An alternative are ozone bubblers.
Expensive models can eb bought in shops or online, complete with timers or even a gauge showing the concentration in a room.
On a hobby level for the kitchen sink we can use an ozone generator, air pump and bubble stone from the aquarium store ;)
Let the pump bubble out the ozone for a minute or two, fill the sink with the fruit and veggies and move them around every few minutes.
Best of course with an open window to limit you exposure to the ozone!
Rule of thumb: If you can smell it is already too much in the air!
The ozone in the water does the same as the peroxide: It breaks down harmful things with pure oxygen.
The downside is that it is very harmful for your airways and body in general, so against all what youtube can offer I actually prefer to treat my fruit and veggie in a sealed bag.
Place them inside, push out as much air as you can and then fill up with the ozone from the generator.
Once the bag is full leave for about 30 minutes then wash and use or place the things in the fridge.


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Jack A Lopez
Jack A Lopez

3 years ago

Well, this is quite a story, or maybe it is poetry, an ode to hydrogen peroxide (H2O2). Let us count the ways, that this compound is useful for stuff.

Everything you write here is true, and I do not suspect any bias, like I would from a web site for a business that sells H2O2.

Although it kind of makes me wonder. Have you recently got into the hydrogen peroxide selling business?

The other thing I was going to say is that whatever you have written about the availability, and legality, of the higher concentrations of H2O2 for sale in your country or region, likely only applies to that region.

I mean, in my country, the former United States, it is easy to find 3% in stores, sold as disinfectant. It looks like 12% and %27 can be found on eBay, at the time of this writing. Although I'm not sure about the purity of the %27 one. That one is a "chlorine free pool shock" kind of product, and the fact it contains %27 H2O2 is only to be found in the fine print, strangely not something the seller wants to brag about.

The odd thing about many of these eBay listings is that it looks like people are looking for 35% H2O2, but nobody is actually selling it. Yet the listing titles include the asinine phrase, "dilute 35%", (logically equivalent to "not 35%") just to catch the eye of people searching for the strong stuff.


"8 oz 12% FOOD GRADE HYDROGEN PEROXIDE (dilute 35% h2o2) (MAKES 32 oz of 3% =2pt)"
"HydroProx 35 (TM) - Pure 35% Food Grade Hydrogen Peroxide (Diluted to 8%), 4 oz"

In fact on Youtube, there are numerous amateur chemistry videos showing us how to make the dilute stuff more concentrated, e.g. by gentle boiling. The water (H2O) part seems to be more volitile, comes off first when trying to boil it.

Of course the reason these videos exist, is because the repressive FUS government, and others, wants to protect their subjects from dangerous chemicals, or terrorists, or something.

Anyway, I thank you for telling us all about the wonderful uses of hydrogen peroxide.

If anyone wants to drag this topic in a different direction, some places to go include:

-o- Ways to concentrate weak store-bought H2O2 to make it stronger.

-o- A way to make H2O2 from the dry distillation of sodium percarbonate


By the way, I have no idea if the process for that would be easy or hard, but think that stuff, sodium percarbonate, can be found in stores in the former US, and also it is a dry powder, which stores well.

-o- Other homemade oxidizers with potential use as disinfectant, bleach, etc.

For example, ozone can be made easily from air and electricity.

Maybe nitrogen oxides can be made from electricity and air also. I am sure I have seen homemade Birkeland-Eyde machines, on the internet (OTI).

Also homemade chlorine bleach via electrolysis of salt water.

Also homemade... every chemical! Have you seen sciencemadness.org? I think they have a wiki too now. They used to be just a forum. The reason I mention that site, is because if you are ever contemplating what would be involved in the homemade synthesis of, whatever, and the related question of, has any amateur ever done this successfully, and are there pictures?


Well then look no further than sciencemadness.org. I mean just include the phrase "site:sciencemadness.org" in your search query, like this,


Potassium permanganate, KMnO4, that's another good one. Rumor has it, this compound used to be available, in dry solid form, sold as a cheap, concentrated, disinfectant. Wikipedia mentions the brand name, "Condy's Crystals"



but I have never actually seen KMnO4 sold as a disinfectant. I've seen it sold as a reagent for water treatment, for, "greensand", type water processors. That stuff is not sold everywhere in the FUS, but likely only in stores in geographic regions that have that particular kind of bad water, necessitating a "greensand" filter, and also eBay for those fortunate enough to live in geography with better water.

It makes me think, there might very well be regions in the FUS with naturally soft water, where the stores do not sell "water softener salt", (for ion exchange water softeners). That is of course the best dollar per kilogram price I've seen for (mostly sodium chloride) salt, or potassium chloride.

Maybe that sort of thing is even cheaper for people who live near the ocean? Neglecting the cost of drying it, and tossing out the seaweed.



Reply 3 years ago

I'm thirsty. Can I please have some H2O too?

Jack A Lopez
Jack A Lopez

Reply 3 years ago

That would be good place to start. I mean if you want to get into the homemade chemical engineering business, and if you want to make all the precursors yourself. Pure water is a substance needed for making a lot of other chemicals, as well as being vital to life itself.

Here is a link to one of Chris Hackett's Rebuild videos, specifically the one where he makes a water-still out of a car windshield.

Also here's what the Sciencemadness Wiki has to say about water,



Reply 3 years ago

No jokes about drinking water please!
Should be a controlled substance if you ask me.
Pure water will kill you if drink enough of it, so really not stuff to joke around with! ;)


Reply 3 years ago





Reply 3 years ago

so beautiful! on par with shakespeare! you could make it into a movie!


Reply 3 years ago

Might be a good idea, considering...
Title: What to do with hydrogen peroxide if you are neither a terrorist nor a drug cook!


Reply 3 years ago

I did not go into the making or illegal uses for the stuff for obvious reason but I just thought old stuff might get new uses ;)
The legal side of higher concentrations is basically taking care that you can not easily buy anything that can be used directly for illegal purposes.
Here in AU the pool grade stuff really is pure and without added chemicals, plus it is legally available at up to 50% concentration.
35% is usually the max you can get without requiring legal documents in bulk.
And no, neither selling, nor promoting to sell - just plain honesty about going back to living and cleaning with less harmfull chemicals.
I think especially considering allergies of all sorts it might be good for some people to take a step and think about how things were done before we had all the TV ads for 50 different cleaning products that we must have in the house. LOL
I used KMnO4 extensively back in the day, both for legal and semi legal purposes but at least in AU it is now very hard to get in bulk quantities or at a decent price.
As with many "good" things it landed on the index of chemicals that could be used to make drugs or explosives.
When I wanted some fine zink powder to make my own anti-corrosion coating I had to resort to ging online and ordering from India as everywhere I asked here I was told I now need a permit to buy and posses zink powder below a certain mesh grade.
Poltical correctness and "terror" protection have turned us into a nanny state where we might soon need a permit to carry our toolboxes in the car or to have a basic toolset for repair on board.
I was already asked what reason I would have to carry a puncture repair kit in car by the cops.
They tried to tell me it could be used as an illegal weapon despite being in a case with the plugs, glue and all - inside a drawer in the back of the car LOL