Spraying Hydrogen Peroxide On Buds: Tips & Benefits

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If you are just getting into the world of growing marijuana, something that you might have seen or heard of people doing is spraying hydrogen peroxide on buds.

Here, we aren’t talking about just spraying hydrogen peroxide on buds that have already been cured, but rather on your plant while it is still alive and growing.

Spraying hydrogen peroxide on buds and weed plants is considered quite safe, and it also comes complete with a variety of benefits.

Now, you wouldn’t just spray hydrogen peroxide just because you can, but rather treat a variety of ailments that may affect your marijuana plants. Let’s take a closer look at what hydrogen peroxide is, and why you might want to spray it on your marijuana plants.

Spraying Hydrogen Peroxide on Buds


What Is Hydrogen Peroxide?

Before we get into talking about why you might use hydrogen peroxide on your weed plants, let’s first figure out what it actually is.

So, hydrogen peroxide is a special type of chemical compound. Its scientific formula is H2O2. When hydrogen peroxide is pure, it is a liquid that is just slightly thicker than water, and it has a very pale blue color.

Hydrogen peroxide can serve a number of different purposes and is often used as an antiseptic, a bleaching agent, and as an oxidizer.

When it is sold to consumers for regular use, it’s usually very diluted, although it may be much more concentrated, especially when used in industrial applications.

As you can probably tell, the antiseptic properties of hydrogen peroxide are what we are really interested in here.

In other words, hydrogen peroxide as an antiseptic has the ability to kill a variety of things including bacteria, fungus, and even insect pests as well.

Benefits Of Spraying Hydrogen Peroxide on Your Cannabis Plants

Marijuana flower buds

There are a variety of possible benefits that come with spraying hydrogen peroxide on your buds. Now, once again, this is not something you just do for the heck of it.

You don’t water your plants with hydrogen peroxide, but rather use it as a treatment for a variety of issues.

Let’s take a look at all of the different reasons as to why spraying hydrogen peroxide on your plants could be beneficial.

1. Treating Bacterial Infections

Hydrogen peroxide is a fairly strong antibacterial agent. Now, marijuana plants developing bacterial infections is not overly common. Moreover, if they do, they can be hard to detect.

Furthermore, bacteria generally only attack weed plants once it has already been weakened by various other factors, such as general stress.

However, when bacterial infections do take hold, they can quickly spread to all of your plants, and they can be lethal.

The application of hydrogen peroxide is a very effective method to kill a variety of harmful bacteria that will quickly kill all of your weed plants.

2. Treating Fungal Infections

One of the most common uses of hydrogen peroxide when it comes to marijuana plants is to kill fungus. There are a variety of fungi, mold, and mildew that can affect your marijuana plants.

Things like very high humidity levels, poor airflow, and unsanitary conditions often cause things like bud rot, powdery mildew, mold, and other fungi to appear.

All of these types of fungi and mold spread very quickly from one plant to another, and they can often cause irreversible damage if they are left untreated.

If not quickly taken care of, these things can kill your plants in a matter of days. That said, some simple hydrogen peroxide mixed with water sprayed onto the plants, and into the soil, should take care of all fungus and mold.

3. Dealing With Pests

pest on weed plant

Another huge problem when growing marijuana plants is pest infestation. There are a variety of pests that like to feed on weed plants and can quickly cause damage.

These include fungus gnats, spider mites, and aphids too. These insects are very resilient, and they reproduce extremely quickly too.

If you see a few of these insects one day, you’re likely to see hundreds or even thousands of them the next week. The issue is also that these insects are very hard to kill when they’re still inside of their eggs or in their larval form.

There are many things that can kill adult insects, but the ones still in the eggs are extremely hard to kill. One of the only things that can kill all forms of these insects, whether adult or in larvae form, is hydrogen peroxide.

Spraying the leaves and watering the soil with hydrogen peroxide is a very effective measure against all of these marijuana pests.

Pests can include the infamous spider mites, even grasshoppers!

4. Dealing with Root Rot

If your marijuana plants are constantly overwatered, the soil is very wet, the soil doesn’t have good drainage, and it is not well aerated, it is likely that root rot will occur.

Roots being too wet for too long will cause root rot. There are also various types of algae, bacteria, and fungi that can cause root rot to occur.

Root rot is unfortunately quite difficult to detect since it is a problem with the roots. This is an issue that often doesn’t show symptoms in the main part of the plant until it is often already too late.

In the later stages of root rot, you will see yellow leaves and branches even falling off the plant. If this is not treated quickly, your plant will die.

Some hydrogen peroxide introduced into the soil will allow more oxygen to enter your plant. Better aeration in the soil may cause water to evaporate quicker and may reverse root for up from occurring.

Of course, the hydrogen peroxide will also kill all of the organisms that may also be causing the root rot to occur.

5. Aerating The Soil

Some people also use a mixture of hydrogen peroxide and water to water their plants on occasion. This has to do with the same thing as we discussed above, mainly soil aeration.

Some people try using hydrogen peroxide as a preventative measure to prevent something like root rot from occurring.

6. Use As A Disinfectant for Tools, Soil, & Seeds

The other benefit that hydrogen peroxide has with weed plants is in terms of general disinfectant. Some people use it to soak their seeds for a little while to kill all fungi and bacteria before planting.

Many people will also use hydrogen peroxide to disinfect all of their gardening tools, and even sometimes the soil before planting or handling the weed plants.

When Should You Use H2O2 On Your Buds?


If we are talking about the actual marijuana buds, the flower that you will smoke or consume, the only time you should use a hydrogen peroxide spray on them is if they have white powdery mildew on them.

Other than that, you really shouldn’t ever spray the actual buds or flowers of your marijuana plant with hydrogen peroxide, the reason why being something that we will talk about below.

If you do have powdery mildew on your marijuana buds, some hydrogen peroxide may be able to take care of it, but there is a huge price that you will pay.

Other than that, although it is fine to spray the weed plant itself with hydrogen peroxide, which means the leaves and the stems, the buds themselves really shouldn’t be exposed to too much of it.

Can I Use Hydrogen Peroxide During Flowering?

If you are actually using the hydrogen peroxide for a reason, then yes you can use it during the flowering stage, right up until the end, more or less.

Just remember that it’s not overly good for the buds themselves, so you really only want to use it if you need to, such as if there is white powdery mildew or some kind of other fungus infection. If possible, just try to avoid spraying the buds themselves too much.

However, if there is some kind of fungus or pest infection, and your only option is to either spray your whole plants from top to bottom of hydrogen peroxide or to let them die, then you might as well give the hydrogen peroxide a shot.

If your plants are already dying, hydrogen peroxide can’t possibly make it any worse.

How Often Can I Use Hydrogen Peroxide on My Plants?

In terms of how often you can use hydrogen peroxide on plants, the answer here is only as often as you have to.

Now, if you are using a fairly weak hydrogen peroxide and water mixture, then you can spray your plants on a daily basis.

You may also water the soil with a hydrogen peroxide solution every few days. Generally speaking, if the solution contains about 90% water and 10% hydrogen peroxide, your plants should be fine if sprayed daily.

However, as we will discuss below, hydrogen peroxide may cause oxidization, so it should really only be used if you have an actual reason.

Most people would strongly recommend against using it as a preventative measure in terms of spraying your plants or watering the soil.

That said, if you have a serious fungal or pest infection, you might need to spray your plants down twice per day. Exactly how often you need to use your hydrogen peroxide solution will depend on the severity of the issue at hand.

Cons Of Hydrogen Peroxide

There are in fact a few fairly big drawbacks that come along with using hydrogen peroxide on your weed plants.

However, these drawbacks generally are not as severe as the problems that the hydrogen peroxide is used to treat.

So, here you are choosing between the lesser of two evils. The lesser of two evils usually is the hydrogen peroxide. That said, what are the drawbacks?

Oxidization & Burning

One of the big drawbacks of using hydrogen peroxide on weed is that it can cause oxidization, especially on the buds or flowers.

Oxidization may then cause the leaves or the buds to burn. This is especially the case if your hydrogen peroxide solution is too strong or if you use it too often.

Possible Stunted Growth

If you use too much hydrogen peroxide and your weed plants end up oxidizing and even burning, it can definitely stunt their growth.

The more of those leaves are burnt, the less your weed plant will be able to take in sunlight. The less sunlight your plant takes in, the slower it will grow. This may also lead to decreased potency and decreased yields.

Loss of Terpenes

If your hydrogen peroxide ends up oxidizing on your weed plants, and even causing burns, it can definitely also reduce the amount of terpenes your weed plant has.

This is actually one of the biggest known drawbacks of using hydrogen peroxide on weed plants, that it reduces terpenes, and therefore reduces flavor and aroma.

It Kills Beneficial Bacteria In The Soil

The other issue with hydrogen peroxide, as far as your soil is concerned, is that it not only kills the bad bacteria, but the good ones too. Hydrogen peroxide will kill beneficial bacteria and microbes.

This can be a relatively big problem when it comes to growing weed in soil. Bacteria and microbes are required in the soil for a variety of reasons.

If your hydrogen peroxide mixture kills off all of those beneficial bacteria and microbes, you might run into some problems.


Does H202 Help with Seed Germination?

Something that even some of the most seasoned marijuana growers don’t know is that hydrogen peroxide can help with seed germination.

You can soak your marijuana seeds in a diluted hydrogen peroxide mixture, and this will help them to germinate much faster.

The hydrogen peroxide will cause the shell of the seed to soften, thus allowing more oxygen to get in. This in turn allows for faster and more reliable germination.

What Else Can I Spray on My Bud?

part of the cannabis plant

If you are having pest or fungus problems, but you don’t want to use hydrogen peroxide, there are a few other things that might be able to help.

  • If you are having issues with fungus, mold, mildew, or pests, one of the best things that you can spray on your marijuana plant is neem oil. It is also safe to use on plants on a regular basis.
  • If you are having issues with white powdery mildew, a solution of milk and water will be able to kill it. Now, this solution will take a few days or even weeks to completely work, but it’s also not detrimental to the plants themselves.
  • Doing a heat blast can also kill fungus and pests, although excessive amounts of heat are also not good for the plant itself.
  • You can always of course use actual insecticides or fungicides, but be sure that they aren’t overly toxic. You definitely don’t want to use these chemicals during the flowering stage, because you don’t want the buds to absorb them. If you do this, you’ll end up smoking fungus sides and insecticides.


There you have it folks, everything you need to know about spraying your marijuana plants with hydrogen peroxide. As you can see, it can definitely provide you with a wide variety of benefits, especially as far as pest and mold control are concerned.

That said, using too much hydrogen peroxide can be detrimental to your plants, so you definitely want to moderate the usage of it.


My passion for the sticky icky started nearly a decade ago, and it all began when I first laid my eyes on the beauty that is the marijuana plant.

I cover all aspects of growing from equipment recommendations to plant health/care tips to help both new and experienced growers.