# H2O2 for Rot prevention?



## Bjorn (Jun 29, 2011)

I am getting fed up with leaves yellowing/browning turning into a smelly mush. You know it for sure - is it erwinia or? Nevertheless some of my paphs suffer severely and the stuff appears -suddenly- on places you would not expect it to. I have seen remedies against it, cinnamon, dragons blood etc. - it helps but not always, so it continues to be a nuisance.
Ok prevention might be better than fixing I thought; so what can be used? The stuff probably spreads by water so if the water can somehow be treated/medicated to kill the germs, the problem could be under control.
I have read on this forum that someone uses Physan 20 (was it Ray?) with good results, but as that stuff both kills moss and is unavailable here in Norway, better choices should be sought. As I like my moss and believe it is important for the well-being of my orchids and a good indicator of things, physan lookalikes cannot be used. As an alternative, I have started adding 
H2O2 into the water and it seems to work somehow. Level is something like 
5ml(35%H2O2) per 10liter, quite diluted in otehr words. I have a feeling that things have improved, and have yet to see any negative side-effects. Furter to the rot-prevention the H2O2 is said to add oxygen to the root-zone which is all good probably. The only negative things I come about is any negative impact on the mycorrhiza. That is however difficult to check.
Are there anyone out there that have experiences similar to mine or are there any contraindications to using H2O2 as germ-killer?
Bjorn


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## goldenrose (Jun 29, 2011)

Here's a previous thread that discussed -
http://www.slippertalk.com/forum/showthread.php?t=5752&highlight=hydrogen+peroxide


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## Ernie (Jun 29, 2011)

Hydrogen peroxide will help clean up a bit and it's pretty safe to use, we use it to rescue crowns that look iffy after a wet cool night or after cutting a leaf, etc. Whatever the typical concentration is from the drug store over the counter bottles, straight (no dilution). H2O2 is an oxidizer, so it can kill anythign living at the "right" (wrong) concentration or with prolonged exposure, but it will take quite a bit IMO. Never watched how it messes with mosses etc. 

But if you're experiencing an ongoing issue with fungus and/or bacteria, look to more basic issues of culture. Usually something's out of whack- temp, humidity, air movement, watering schedule, mix freshness... I'd start by trying to improve air movement.


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## NYEric (Jun 29, 2011)

I read here about it but I would prefer to clean (Physan) then use something dry (lime powder) or in thick quick drying solution (Dragon's Blood) than a wet solution against a humidity vectored/fermenting problem.


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## biothanasis (Jun 29, 2011)

Hi,

I would be very cautious in using H2O2 on roots or the rythm I would use it or the time it stays in contact with them, as it tends to destroy them. Additionally, as long as it stays at a 3-3,5% concentration, it is very good or helps at cut dissinfection , crown rot treatment etc. 

Any probable change in cultural conditions would help a lot (e.g. ventilation), too, as Ernie & Eric suggested.

Good luck!!


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## Rick (Jun 29, 2011)

Bjorn

Over the years I'm finding that frequent problems with erwinia could be due to nutrition problems.

My biggest focus these days is an overall excess of pottasium (from standard balanced fertilizers) building up in the potting mix, causing deficiencies of calcium and magnesium.

From a general culture system you might look at the sphag/basket system I posted a thread about coupled with reduced fertilization and spiking with extra magnesium (from Epsom salts).

Peroxide is quickly degradable, so unless you are using very frequent applications, it is not very effective as a prophylactic.

In general its an oxidizing substance so it's not inconcievable that you could add very small quantities to your general use/irrigation water, and spray enough to get in the leaf axials on a daily basis. But I am not aware of any studies that can give you a dose for it.

Also bacteria are tough, and I wouldn't be surprised if long term use could eventially lead to resistent strains of who know what.


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## W. Beetus (Jun 29, 2011)

biothanasis said:


> Hi,
> 
> I would be very cautious in using H2O2 on roots or the rythm I would use it or the time it stays in contact with them, as it tends to destroy them. Additionally, as long as it stays at a 3-3,5% concentration, it is very good or helps at cut dissinfection , crown rot treatment etc.
> 
> ...


 
Just to note- Store bought bottles of H2O2 in the US are at a 3% dilution, so it would theoretically be okay to use straight from the bottle. I don;t know about the standards for other countries.


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## SlipperFan (Jun 29, 2011)

The thread that Rose referred to has a link with an article that talks about proportions. I tried it once. No ill effects, in fact, I think my plants became healthier afterward. So I'll probably do another dose in the near future.


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## Bjorn (Jun 30, 2011)

There seems to be some uncertainty regarding my original posting so below I elaborate a bit on that topic trying to explain the idea and rationale behind using H2O2. 
I might have been a bit unprecise in stating erwinia as the culprit, it may very well be phytium or phytophora, the symptoms are in may cases very similar and the conditions for rapid multiplcation are similar. High humidity and temperature. In the case of Erwinia, i found this description on the web site of Hark http://www.hark-orchideen.de/Pflanzenschutz/uebersicht.php?lang=en&navID=99


> "Bacteria are unicellular rod-like organisms that move actively in the water with the help of flagella. Reproduction is done by division and only takes a few minutes in a humid and warm environment. Bacteria are not able to infest a healthy plant surface, they always need open parts such as wounds or gaps. Most bacteria reach their optimum in high temperatures between 25°C and 30°C and high humidity, so repeated explosion-like infestation usually has to be expected during the summer."


For Phytium/pythophora the following is found:


> Characteristic features of these fungi are round to lemon-shaped sporangia. This is where the flagellate zoospores are formed that makes the causative organ spread. Sufficient humidity is the decisive factor for multiplication and spreading of the fungi in the plant stand. Constant substrate humidity helps to grow fruiting structures and zoospores. Spraying or irrigation spreads the rot from plant to plant. Most Phytophthora species prefer high temperatures and sufficient humidity, many other fungi, however, grow best in cool and humid conditions. The fungi intrude their host plants with the help of specific enzymes and excrete toxic substances in them. Within a very short time infested plant parts may decompose and there will be extreme soft rot. Whereas Pythium only infests underground plant parts as a parasite, Phytophthora may occur on all plant parts.


The common denominator here is water; these things use water to spread and infest. Where do we find water? Oh yes, it comes from watering, right?
By overhead watering (which is necessary for larger collections of non-uniform plants and pots) water gets trapped in the crown and the leaf axils and this pool of water serves as the entry of the pathogen.
Then, what to do?
1) dry the water asap- this can be done by air circulation(fans) watering in the morning, be slightly restrictive on watering and misting (this is difficult!) etc. Helpful but not always "fool-proof". If the weather stays dull, the residence time of that water may get extended. So it stays a "swimming pool" for these pathogens searching for a point of entry.
2) kill the germs. This is the core of my idea. If the "swimming-pool" contains chemicals that kills or at least "knocks out" the pathogens, the likelyhood if infection would be reduced.
It is under 2) that my suggestion of H2O2 comes. 
I use it at every watering in all water at a concentration of approximately 0.0175% or 175ppm. that is a dilution rate of 1:171 if 3% H2O2 was used. Ridiculously low right? Might have to increase the dosage, but better start at the safe side.
It seems to help though. But not 100%. I get my H2O2 from a hydroponics shop at a strength of 17.5% that is burning when you get it on your skin! At a 1000:1 dilution i hope it kills the zoospores(its probably phytophora we talk about) breaking the reproductive chain, at least to some extent.
H2O2 is not long lived, it disintegrates to H2O and O-radicals that oxidises anything it gets in contact with like zoospores. In the soil, it should more or less immediately react and disappear.
Is H2O2 only available at 3% strength in the US nowadays? If so, the reason is of cause that stronger versions of H2O2 can be used to make acetone peroxide, an unstable explosive, claimed to be a terrorist favourite. Thats why you are not allowed to bring liquids onto airplanes anymore btw.


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## NYEric (Jun 30, 2011)

Try it but I still go with the "dry" solution.


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## Leo Schordje (Jun 30, 2011)

available in the US through hydroponics stores or greenhouse supply houses is a product called Zertol, another called H2O2 by Nutrilife, both are roughly 29% hydrogen peroxide. They are much cheaper to use than buying 3% peroxide from the local pharmacy. The lit suggests using it for algae contol. I use it pretty much as John suggested, but I use it at a much higher dose, roughly 0.25% during the (relatively brief) week long episodes of hot and humid weather we get living along the west shore of Lake Michigan. I had to change the ventilation pattern in my basement grow area, as a result, during 90+ F weather, the ventilation does not allow proper cooling at night. Seems to help, I like the clean smell watering with this solution has.


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## W. Beetus (Jun 30, 2011)

I actually use H2O2 in the form of Sodium Percarbonate for algae control in my pond. When introduced with water, I believe it breaks down to roughly 30% H2O2.


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## SlipperFan (Jun 30, 2011)

W. Beetus said:


> I actually use H2O2 in the form of Sodium Percarbonate for algae control in my pond. When introduced with water, I believe it breaks down to roughly 30% H2O2.



That's interesting. It kills algae but is not harmful to plants and aquatic critters?


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## Bjorn (Jul 1, 2011)

Guess my dosage should be increased then. Another thing that may prevent the rot is of course to restrict my watering somewhat. It is not a too big problem though, but is a nuisance for some plants and seedlings so I would very much like to suppress it as much as possible without sacrificing my "natural growing" regime.


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## goldenrose (Jul 1, 2011)

W. Beetus said:


> I actually use H2O2 in the form of Sodium Percarbonate for algae control in my pond. When introduced with water, I believe it breaks down to roughly 30% H2O2.





SlipperFan said:


> That's interesting. It kills algae but is not harmful to plants and aquatic critters?


My husband talked to someone who uses it & forwarded some info to him about it, that was after I bought the gallon of Microbe-Lift for $75! If I recall correctly it's beneficial for the fish in helping to control bacteria/pathogens. Guess I'll have to wait til next year ......
if I remember!


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## Ray (Jul 1, 2011)

I started using Zero-tol more regularly since they came out with a "Ready to spray" (RTS) bottle that attaches to the hose end. It is about 5% H2O2 in the bottle, and that is diluted 150:1 by the sprayer, and as Leo said, it is very effective at keeping algae and most fungal/bacterial diseases at bay, with no I'll effects on plants at all. 

It is stabilized with peroxyacetic acid, which apparently makes it farmmore effective than the 3% stuff.


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## SlipperFan (Jul 1, 2011)

goldenrose said:


> My husband talked to someone who uses it & forwarded some info to him about it, that was after I bought the gallon of Microbe-Lift for $75! If I recall correctly it's beneficial for the fish in helping to control bacteria/pathogens. Guess I'll have to wait til next year ......
> if I remember!



Thanks Rose. I'll check it out.


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## biothanasis (Jul 2, 2011)

Beetus, we have the same concentrations of available here too (3%) from the pharmacy. 

I said about being cautious with the roots because I let some chiloschista seedlings on H2O2 (3%) for some minutes (do not remember how long exactly) and they were completely destroyed (became mushy without the ability to turn back to normal). Well I have no idea how will affect oots of adult plants and how each species react.


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## myxodex (Jul 3, 2011)

Interesting thread ... I've considered using it myself. Rainwater contains H2O2 caused by ozone oxidation and ozone levels are increased in electrical storms common in the tropics. The point is that in nature plants are watered with highly oxygenated water containing H2O2. My problem is that I have to collect and store rain water and during storage the contaminating nutrients in the water I collect is more than sufficient to allow the growth of bacteria that use up the oxygen ... stagnant water will have low oxygen levels and I suspect is not ideal for watering plants. I used to have a set up in which I used an aquarium filter stuffed with activated charcoal to "freshen up" stored water for a day or two before use in an old aquarium ... the agitation and circulation of the water would have produced oxygen saturation and the charcoal reduced the organic load which accumulated in the in the water. I think stagnant water can be a potential problem.


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## cnycharles (Jul 3, 2011)

if you store water in a tank you can use an airstone bubbler for aquariums. will stir and oxygenate. we used to use zerotol at work on seedlings and cuttings at a certain rate in the water, and it worked fairly well. though, that was before our chemical purchases were cut back so we don't have it. there is higher concentration food-grade h2o2 available that can be used for personal health and cleaning of food contact surfaces but don't know the name or pricing. there are studies that have been done using irrigated h2o2 on misted cuttings and things like that, which showed at a rate a bit lower than pharmacy rate controlled disease and didn't show damage, also being used for killing insects. I did see some damage on some of my phals the third time out of the bottle... but used a short time apart


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## NYEric (Jul 3, 2011)

If I used the [3% (stabilized)] hydrogen peroxide from the store to try to treat rot would I dilute it with RO water and if so at what strength.
OK, I when back to the linked thread and see its straight out the bottle, now to look for troubled plants!


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