The Best 7 Remedies For Mosquito Larvae In The Rain Barrel

Probably you are very happy about your rain barrel with which you collect free rainwater all year round. But especially in summer you might have the problem to be haunted by mosquitoes.

So like me at first you ask yourself now which means against mosquito larvae in the rain barrel really help?

Tipps gegen Mückenlarven in der Regentonne

Overview of the best 7 remedies against mosquito larvae in the rain barrel

Before I go into more detail about the seven different tips against mosquitoes in the rain barrel, I would like to give you a small overview of all the possibilities.

In particular, I have compared all means and tips on the basis of cost and effect and have come to the following conclusion:

remove surface waterGreat effect, as simply skim all the mosquito larvae and land on the bedNo cost, as surely everyone already has a watering can* at home
cover rain barrelGreat effect if you make sure that really no more loophole is open
is open (bin can be covered with lid or mosquito net)
Depending on the lid* or mosquito net*, one-time costs of approx. 10-20 dollars arise
biodegradable washing up liquidMedium effect, which can vary in strength depending on the rinsing agentBiodegradable dishwashing detergent* costs approx. 3€ per 1 liter
commercial repellentsVery effective because certain bacteria in the repellent kills all mosquito larvae Neudorff costs approx. 15 for 10 tablets (10,000 liters).
destroy surface tensionHigh effect, as mosquito larvae can only survive in stagnant water with high surface tensionRelatively expensive, as constant movement can only be generated by a pump
keep fishMedium to high effect, because depending on the fish species and the rain barrel or location, the fish are more or less lively and eat the mosquito larvae all completelyMedium cost; purchase of fish relatively inexpensive, but they still require additional food
vegetable oilAlthough a medium effect, but possibly with side effects, as the water can become rancid and begin to stinkDepending on the oil about 1-10 dollars, however, for the rain barrel of course the cheapest oil would be sufficient

If you want to know more details and practical advice about each option and repellent against mosquitoes in the rain barrel, just read on 🙂

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1 remove or skim surface water from the rain barrel.

First of all, let’s look at the cheapest and yet very effective tip:

To water, simply always skim the water off the surface of the rain barrel and use it directly.

This way you make sure that mosquito larvae, which are on the surface of the water, can’t develop further. On the contrary, as soon as they land on bed soil they dry out immediately.

This tip against mosquitoes in the rain barrel is very simple and does not require any additional material or purchase of tools.

Just use a normal watering can* or alternatively a small container* for skimming.

2 cover rain barrel to keep mosquitoes away

The second, also very simple and comparatively inexpensive tip to prevent against mosquitoes in the rain barrel:

Cover the rain barrel!

There are several ways to do this, but they can all be equally effective, provided that the rain barrel is actually completely covered and does not give mosquitoes a chance to lay larvae.

The following variants are available to cover a rain barrel:

Covering a rain barrel with a lid
Classically, you can cover a rain barrel with a lid*.

This variant is suitable above all for conventional rain barrels which were bought in the building market.

For some models, a lid is already included in the purchase or can alternatively be purchased later.

With alternative or self-made rain barrels often no suitable cover is present or to be acquired.

In this case, you can build one yourself from wood, for example, or you can cover your rain barrel with the second alternative…

Cover rain barrel with fly or mosquito net

A simple and inexpensive way to cover the rain barrel is to make your own cover with a fly or mosquito net.

Both fly and mosquito nets are available for purchase at very reasonable prices, such as here at Amazon*.

Especially for rain barrels that do not have a standard size, it can be useful to make your own net cover.

However, if you don’t want to do that or have a standard rain barrel, you can just buy a matching mosquito net (this one* even has a drawstring to tighten the net properly)….

If you cover your rain barrel to prevent mosquitoes, you need to make sure that water can still get into the barrel when it rains.

Therefore, it is important that you make an appropriate hole in the lid or the net cover, which, however, is tight on all sides.

3 biodegradable washing-up liquid against mosquito larvae.

Let’s move on to a real home remedy against mosquitoes in the rain barrel: dishwashing liquid!

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This all-rounder is easy to dose, about 3 tablespoons of dishwashing liquid per 500 liters of rainwater.

The dishwashing liquid floats on the surface of the water or destroys the surface tension, which destroys all mosquitoes and mosquito larvae.

The positive thing about the detergent is that the rainwater cannot become rancid or start to stink.

On the contrary, the water can become slightly foamy, depending on the amount and type of detergent used.

This is not a problem as long as you make sure that you use 100% biodegradable detergents.

100% biodegradable detergents leave no chemical traces in nature and are therefore completely harmless.

So what kind of biodegradable dishwashing detergents are out there and where can I buy them?

From experience, I know that there are various biodegradable dishwashing detergents available at the drugstore dm that are also very reasonably priced (e.g. from ecover* or Sonett*).

4 commercial repellents against mosquito in the rain barrel.

In addition to all the preventive measures and home remedies against mosquitoes already mentioned, there are of course also repellents to buy.

This is a purely biological preparation that destroys mosquito larvae, but does not endanger fish, dragonflies or other animals.

You should use one tablet per 1,000 liters of rainwater and simply throw it into the water.

But how does the mosquito-free from Neudorff actually work?

The tablets contain bacteria that have a toxic effect on mosquito larvae. The bacteria produce a special type of crystalline proteins that have a negative effect on various insect and mosquito species.

But don’t worry, the bacteria or repellent is completely harmless to humans or your vegetable patch because it is completely biodegradable.

5 destroy surface tension to expel mosquitoes from the rain barrel.

Another way to prevent against mosquito larvae is to destroy the surface tension in the rain barrel.


Because mosquitoes breed only on calm water and only through the surface tension the mosquito larvae can breathe and stay on the surface.

So if this tension is destroyed, you take away the mosquito larvae’s livelihood.

To destroy the surface tension in the rain barrel, the water should be in motion.

The best way to achieve this is to use a pump that keeps the water in constant motion.

However, I personally would not recommend to buy a pump only for the rain barrel. Either you filter the rainwater with the pump at the same time (which is not necessary if you only want to use it for watering), or you try one of the other 6 tips against mosquito larvae in the rain barrel.

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6 keep fish in the rain barrel

What many people don’t know is that you can even keep goldfish or other small fish in the rain barrel – and they even have a great benefit:

Goldfish namely eat the mosquito larvae in the rain barrel!

Besides goldfish, you can also keep guppies or cardinals in the rain barrel if it does not get too hot in the barrel and you overwinter the animals properly.

In fact, goldfish, for example, feel very comfortable in murky, somewhat dirty water. They like to dig in the bottom of the water, which is possible in a rain barrel.

The positive side effect is that they eat the mosquito larvae.

So you kill two birds with one stone: you can keep a few small fish and at the same time contain a possible mosquito plague.

The only thing you have to be careful of is that when you take out water, you have to make sure that the small fish stay in the rain barrel and don’t get into the watering can.

7 some tablespoons of vegetable oil help against mosquitoes in the rain barrel

Now we come to the last tip against mosquito larvae in the rain barrel. This one is especially relevant if you already have mosquitoes in the rain barrel.

A very simple home remedy against mosquito larvae in the rain barrel, which probably everyone has handy, is vegetable oil!

Per 500 liters of rainwater you can use about 3 tablespoons of oil.

Since oil is known to float on the surface and you know by now that the water surface is the habitat of mosquito larvae, you kill the larvae with the oil.

However, there can be a downside to using oil as a mosquito repellent:

Oil can (but doesn’t have to) become rancid over time due to temperatures and weather and start to stink.

If your rain barrel is located e.g. directly next to the terrace, I would rather fight the mosquito larvae differently.

However, if your rain barrel is located in a secluded place in the garden, where possible odor does not bother anyone, you could certainly try oil once.

Now you may wonder if the tips and household remedies against mosquitoes work only for rain barrels!?

No, don’t worry! The tips apply to all standing water.

So if you have problems with mosquito larvae in other areas of your garden, such as standing water in planters, flower pot saucers, or in a standing pond, you can try all these tips there too.

Depending on the size, one or the other tip is of course more or less suitable or you have to adapt the quantities to the respective volume.

Now it’s your turn!

If you have a mosquito problem in your rain barrels, try one of the 6 tips described above and write in the comments below how it worked for you!

Also, feel free to let me know if you have any other ideas and tricks up your sleeve for fighting mosquitoes in rain barrels.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts.

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