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H2O2, Hydrogen Peroxide, Peracetic acid

Just wanted to post some factual information on Hydrogen Peroxide (H2O2).
#1 Hydrogen Peroxide is a superb SURFACE disinfectant and even works on microbes which are resistant to chlorine (bleach) or antibiotics!
#2 I say SURFACE disinfectant because Peroxide is quickly neutralized by the ubiquitous enzyme peroxidase found EVERYWHERE in nature. The peroxide is quickly converted to water and oxygen (H2O and O2). One of the problems is that if you put Peroxide in tap water you will actually loose some of it’s effectiveness right there as it is already reacting with water borne microbes…or existing peroxidase.
#3 In order to get more effective disinfection with Peroxide, it is often bought as Peracetic acid. Peracetic acid is the usual material bought for ag or commercial disinfection. Peracetic acid is Peroxide combined with Acetic acid. the Acetic acid buffers the pH, thereby extending the effectiveness of the Peroxide component while it’s in solution.
#4 Once peroxide is applied to a surface, whether straight or in Peracetic acid, it acts very quickly and will normally be fully neutralized in about 60-90 seconds.

So what you have is EXCELLENT disinfection and destroying of most any microbe it contacts…however, there is essentially NO RESIDUAL control. So if you are treating a disease like PM you will need to do daily treatments until under control. The good thing is that peroxide is not terribly expensive.

Interesting side note from a plant physiology perspective, is that there is some peroxidase found in the cellular cytoplasm of all plant cells. It is one of the primary agents that destroys IAA (Indole 3 Acetic Acid) The main natural plant growth regulator! Mama nature gives with one hand and destroys with the other!! FWIW


I have question about mixing H2O2 to to treat water/fertilize tank , how it reacts with micro/macro nutritions , i know that neutralize Iron , can H2O2 lead to iron deficiency or some other element ? And what will be the dose to treat water , i know depends from the organic things in the water , but i have read some people use 34% from 2 TSP on 100 gallons to 500 ml to 100 gallons .


Thanks for your post and all the info, @rflasch! I’d be curious to know your position on hypochlorous acid. It’s a subject that has been coming up more and more on the forum recently and I would love to hear about it from you. What are your thoughts?

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Your question is a tuff one to answer. I am not sure what you are trying to accomplish with your Iron content… all peroxide liquids are chemically oxidizers. In the rhizosphere (especially with various media) you must understand there are complex chemical reactions that must be considered. Remember the peroxide will not remain active for long, and there is a plethora of organic acids in your media that will continuously effect your available Iron. (i.e. these organic acids affect pH and therefore the Availability of your Iron as well as other metals)
Perhaps the best thing I can do for you is provide a link for a 5% product that is most often used in commercial ag.

You will note there are many formulation strengths available and suggested dilution ratios for many applications…hope this helps


Nick, to simplify our discussion I will group all hypochlorous/hypochlorate products together as bleach!
Very good for hard surface disinfection! So if you are disinfecting your grow room or processing equipment, workbenches, etc. It is a cost effective and reliable material to get the job done! Bleach does have some residual efficacy that peroxides lack. Be aware of mixing bleaches with any other cleaners as chlorine gas is toxic!

My opinion is that if you are using bleach to sanitize anything that will actually contact the plant (grow bags) let them dry out in the sun and rinse with water before putting back in use. Chlorine is never good for plant growth…another reason I advise choosing potassium sulfate over potassium chloride in your soil nutes!


Great advice, Bob! Thanks for the explanation and detailed clarification!


Two samples of creek water after 3 days . Above is treated water with H2O2 , below untreated water . The brown color is a sign of pathogens presence of Pythium and Phytophthora , pathogens responsible for ROOT ROT (brown roots ) and DAMPING OFF .


Great demonstration of peroxide effectiveness! Your treated bag shows that the peroxide did it’s job and destroyed microbes in both the water and on the leaf surface. Since the bag was sealed you maintained a ‘sterile’ sample. Your untreated bag obviously had microbes in the water and on the leaf surface. The anaerobic conditions in your bag initiated tissue breakdown of the leaf and probably a plethora of anaerobes starting digestion.

Since Pythium and Phytophthora are soil borne pathogens, I am guessing you believe you have them in your creek water. I now assume you are treating your potted plants ‘soil’ with peroxide to remove those pathogens…is that correct?

In that case I assume you would be treating ALL your creek water before using it to irrigate. Here is your issue to consider…peroxide is a indiscriminate killer, so indeed your peroxide will remove most the pathogens. However, you have a tremendous number of BENEFICIAL fungi and bacteria that are going to have a equally difficult time surviving. If pathogens in your water are your major problem a much more productive approach (IMHO) would be using a carbon filtration/reverse osmosis unit to eliminate all microbial content in the water. These units are available world wide and very scalable, in that you only need to purchase the size unit that will purify the gal/Lt per day that you require. I hope I understand your goal and have offered a better solution… good Luck


We are growing mostly hydroponics , peat moss soilless media with regular synthetic feedings . So the bio activity in the medium is not huge concern for us . We treat the storage water tanks , so by the time the treated water comes to the mixing tanks most of H2O2 is neutralized . I have seen studies that show that 50% of the peroxide is neutralized in the same day and in 4-5 days there is just small amounts. RO is not the best sanitizer , as i know is good for filtration it can also sanitize but its not first choice for sanitizer, for two reasons : 1. There is some contaminant that cant be removed ; 2.Membrane deterioration can occur due to the bacteria .


I would strongly disagree with equating hypochlorous acid with bleach, as their safety, toxicity, and efficacy could not be more different.

Hypochlorous acid is 80 to 100 times as efficient as bleach, but is totally safe and non-toxic and requires no PPE aside from common sense (I will spray our HOCl disinfectant in my mouth and would never do so with bleach). While it is indeed a great hard surface disinfectant at 500 ppm, it can deliver a wide range of benefits at much lower strengths.

Our HOCl product, GroWash, is currently being used by growers for plant wound care during trimming. With just a spray bottle of 100ppm GroWash and a pair of scissors you can dramatically lower the stress levels of your plants while trimming, resulting in stronger, healthier plants.

We are also safe and effective to use for cloning as we help cut plants stay fresher longer. By way of analogy, GroWash can more than double the lifespan of fresh cut flowers, as we keep cut plants and flowers clean so they can actually drink their water. I’ve had 5-7 day roses last 17-21+ days in my home experiments.

Plants naturally produce hydrogen peroxide under stress as a defense mechanism, so pure HOCl is essentially a performance enhancer for plants. This is quite different from spraying plants with bleach, which would be harmful as you say.


I’m glad you are having good results with HClO…however, you are conflating two sets of facts in your final paragraph…Yes, it is true that plants do produce hydrogen peroxide …you are incorrect when you say ‘which then converts into HOCL’. Sorry, but HOCL has nothing to do with H2O2. You may want to check the simple chemistry on Wikipedia. Hypochlorous, hypochlorate, hypochlorite are all just ‘bleach’ at different oxidation levels.

I am pretty confident that if you did use Hydrogen Peroxide alone (instead of HClO) for wound protection and preservation of cut flowers you would attain the same results without any Chlorine at all. Thank you for your contribution.


Eldin, understanding better now what your situation is, I would really think you would attain some advantage using peracetic acid to treat your storage tank vs. straight H2O2.


Actually i do use peracetic acid , i use ZeorTol 2.0 and i plan to switch with Sanidate 12.0 because of the price .


Thanks for the correction on the conversion, I have removed that assertion; I had heard of a study in which a team at the University of Arkansas had used bovine MPO on plants to produce HOCl from their H2O2, but after inquiring further it looks like they were unsuccessful. I couldn’t find the study, but this student paper discusses the MPO+H2O2+Cl- mechanism in animals:

I still disagree on the bleach at different oxidation levels comment as we are talking HOCl versus NaClO. We don’t call H2O2 water at a different oxidation level, we call it hydrogen peroxide, and vice versa. Along the same lines even though the empirical formula for glucose would be CH2O (aka formaldehyde), it’s molecular formula is C6H12O6, because atoms and structure matter a great deal, especially separating poisons from food or other beneficial compounds.

Thanks for the discussion and Happy Fourth of July! Hope it was a great one!


eldin, I understand your concerns regarding RO systems, however for purposes of education on this subject, RO systems have come a LONG way! I want to provide a link here so that any growers can get information to address any particular problems they may have… in many cases microbial contaminants may be removed and excellent water quality achieved through filtration/treatment without RO.

This is a great company at designing systems to meet your particular needs. If you can get a comprehensive source water sample they WILL be able to address your specific problems. They are easy to work with and will quote your complete system. ( For transparency’s sake, I must say that we purchased a 1800 GPD filtration/RO unit from them for our formulation plant)

I do hope this thread has provided some insight for all!!!


What do you think about producing H2O2 through your HVAC system ?