Does This Viral Rain Barrel Hack Really Work?

Updated: Aug. 29, 2023

Will lemongrass solve your rain barrel woes? Find out if this hack actually repels mosquitoes and kills algae.

If you don’t have your rain barrels set up the right way, you’re probably searching for a solution to algae-ridden and mosquito-infested water. A lemongrass hack that’s been popular on TikTok recently might seem like a godsend.

But is it really?

My rain barrels require little maintenance, other than a good scrub with Dr. Bronner’s castile soap once a year. And I don’t need to add plants, essential oils or chemicals to keep out algae or pesky mosquitoes. But let’s examine this supposed miracle hack for keeping your rain barrels clean and free from mosquitoes, as well as some alternatives.

@saltyacresnc Lemongrass is a must have for your garden if you have a rain barrel! It helps keep your plants healthy and helps keep mosquitoes away. #gardenhack #lemongrass #rainbarrel #gardening #garden #gardenproject #gardentips #diygardening #essentialoils #farmer #plants #plantsoftitkok ♬ original sound – Salty Acres

How This Rain Barrel Hack Is Supposed to Work

The premise: Lemongrass contains citronella oil, which repels mosquitoes and kills algae — all true. At first, you might think you’ve stumbled onto a winner. At first.

However, I wouldn’t do this with my rain barrels. Introducing plant matter to a barrel of water that needs to be cleaned is not a good idea. The plant matter eventually decomposes, providing food for bacteria and other types of algae.

Plus, the root cause of your problems is still there: You still have an uncovered rain barrel full of stagnant water. And if you’re like the guy in the video, you also have a light-colored barrel prone to algae growth.

The thing is, the citronella and other volatile oils in lemongrass aren’t the potent essential oils you’re familiar with. Creating essential oils from plants requires distillation and extraction, which can’t be replicated in your rain barrel.

You also need a huge amount of plant material. Lemongrass essential oil production requires around 320 pounds of plant matter to make one pound (16 ounces) of oil, using steam distillation. A few little clippings of lemongrass added to your rain barrel won’t be terribly potent.

Alternative Methods

unknown female with hands in clean rain barrel collection tankokugawa/Getty Images

There are much better ways to keep rain barrels clean and free of insect pests. It really comes down to choosing the right barrel, setting it up properly and doing a little maintenance every year.

  • The right barrel: Choose one that’s large and dark-colored. Darker colors block light from getting into the barrel, and algae needs light to grow. You can even set up a series of barrels connected by hoses, so that when the first one fills up, the excess water flows into the next barrel, and so on. Just make sure they’re all dark.
  • Cover it up: Get a dark, tightly fitting lid. This stops animals and insects from getting in, and further blocks light to inhibit algae growth. If you’re still worried about mosquitoes, add a mosquito mesh cover underneath the lid as an extra layer of protection.
  • Provide shade: If possible, position your rain barrels in the shade as much as possible. Reducing strong sunlight reduces the likelihood of algae growing in the water.
  • Regular cleaning: Every year, empty your barrel and give the inside a good scrub. I use Dr. Bronner’s castile soap because it’s natural and won’t harm my plants if there’s any residue left in the barrel.

What To Do If You Already Have Problems With Your Rain Barrels

If you’ve got mosquitoes but no sign of algae, add some vegetable oil to the top of the water. It sounds weird, but it’s no weirder than adding lemongrass, and this is more effective.

The oil sits on the top of the water, creating a barrier the mosquitoes can’t penetrate to lay their eggs. And if you’ve already got eggs, larvae, or nymphs in your barrel, adding this layer of oil suffocates them and blocks oxygen transfer, too. Then cover the barrel so no more insects can get in.

If you’ve got a little algae and act quickly, adding a cup of vinegar to the water, then covering the barrel, can kill it and prevent regrowth. It will also help control the mosquitoes.

However, if the problem is more extensive, you’ll need to empty the barrel and give it a thorough cleaning. Scrub the inside with a mix of Dr. Bronner’s castile soap and vinegar. Then rinse with plenty of hot water and reset your barrel correctly, as above.

And remember: If you’re harvesting water from your roof, even with gutter guards, some debris will likely make it through into the barrel. While small amounts of debris, bird droppings and even small drowned rodents quickly break down in the water and aren’t really a problem, large amounts will cause issues over time. So annual cleaning makes the most sense.

The Verdict

I wouldn’t recommend the lemongrass-in-the-rain-barrel hack. There are more effective methods to resolve the problem and prevent future ones, none requiring a huge amount of effort. Stick to keeping your barrel in good condition, positioning it in the shade, and doing a little yearly maintenance.