How do I apply hydrogen peroxide?

Hydrogen peroxide is beneficial as an addition to nutrient feeding programs at all times. It feeds the good aerobic bacteria and kills the bad anaerobic bacteria. It also introduces radical oxygen atoms which oxidize elements, making them more available for the roots to assimilate. I apply 3% H2O2 at a rate of 30ml/gallon to the reservoir. The plants show no visible signs of stress afterwards, which indicates that it was not an excessive application.

Sprouting Seeds: add 30ml 3% H2O2 to 1 pint of water. Soak the seeds overnight.
Insecticide Spray: combine 250ml 3% H2O2 to 1 gallon spray mix.
Fast growing container plants: add 30ml of 3% H2O2 to 1 gallon water.
Hydroponics: apply 3% H2O2 at a rate of 30ml/gallon to the nutrient reservoir.


Great info, thank you

you can apply directly to the wound, or moisten a cloth and apply that way as well :laughing::grin:


Just wondering if added to bong water, it would attach to CO.

Could be a heart saver.

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Thank you. Ive heard about adding HP to the water. I fear a couple plants root systems could use some strengthening. I dont want to compound a issue by fertilizing. Plants are nice green. The roots are suffering tho. Does it help with gnats?


It helps with gnats but won’t kill them all plus you have to deal with the gnats’ larvae - stick some kids play-sand on top of soil when using it and that’ll stop the little c**ts in there tracks - i had a bad outbreak :mask: for ages, just now about to close out my perpetual growing to finally rid myself of the wee bastads…
Good luck with the gnats bud …


i combated gnats for a while during winter and they went away completely after the last application of nematodes and yellow sticky traps, although it coincided with the change to summer so maybe the warmer temperatures and higher humidity helped ? :confused:

i’ve heard watering with hydrogen peroxide works good for combating gnats / killing larvae … i tried it as well, not sure how effective it was

I’ve had success using 250 ml per liter of water to combat mold.showing no signs of stress 2x applications a day. Is this just an anomaly

When watering with Hydrogen Peroxide do you add nutrients to the water also?
Also do you adjust the PH after adding the peroxide?

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This is a good question… I’m not really sure the
answer but I’d say you would be safe to PH after you mix everything just as you normally would. That is what i would do.

been reading up on this. supposedly it can be diluted with water sprayed on to treat molds and bugs with no ill affect. also poured on roots to fix root rot issues. it oxygenates the roots as well as kill the bacteria that causes the rot. anyone ever do this for your plants? when mixed with water it degrades into pure water and O2 . seems it would be a good to use for final flush also or for a plant over fertilized…

I’ve been using peroxide in various amounts for different things. Problem with using a stronger mix is it would also kill off good microbes in the soil, but you could always re-inoculate. But over feeding may not be one of the problems it’s good for, depending on your fertilizer. But using it following a heavy flush would be a good idea to prevent the over watering issues.

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i thought that maybe a flush with water and peroxide to runoff would be good to remove excess nutes and oxiginate the roots at the same time. if i ever run into that situation again ill try it. nice thing about growing organically you rarely over fertilize but i suppose it still could happen.

Yea I think the problem if your using organic then the peroxide might break it down faster and actually flush more nutrients into the soil

H202 is great in water cloners to prevent algae. Thats all i use it for.


What ratio or rate do you add it? IOW - how many ounces per gallon of water in the cloner? Also, what strength of H2O2 do you use?

I just use 3% over the counter stuff, but it goes quick. I haven’t gotten the stronger stuff yet

Tying to find the link for root rot and fungus gnats.


3 percent h202 at 1/2 cup per gallon. My cloner holds 2 gallons. I use unfiltered tap water.


Ah, I didn’t see this thread before either lol.

Pretty useful Arriba|nullxnull , is there a metrics version? ejem|nullxnull Thanks for sharing … beer3|nullxnull