How To Spray Houseplants With Alcohol (And Why)

alcohol as pesticide

If you have indoor potted plants, they generally add to the room’s aesthetics and brighten it up a bit. The last thing you would like to see on your cherished plant is bugs, slugs, and critters!

You can spray houseplants with alcohol to control destructive bugs and insects. Alcohol is an effective insecticide and herbicide and is often used to control weeds. Used with caution, alcohol can speed up or slow down houseplants’ growth, giving you control during the growing season.

Thankfully there are many different ways to get rid of unwanted bugs without using chemicals or dangerous toxins. Alcohol might seem like a nasty substance to spray onto your plants to fight bugs and unwanted critters, but it can be effective when correctly used in the right amounts and products! In this post, we discuss why alcohol can be used as an effective, non-toxic plant protector!

Why Would You Spray House Plants With Alcohol?

Insects will attack and kill your house plants if they are allowed to. Mealybugs, aphids, mites, scale, whiteflies, and fungus gnats, love to feed on your plants and will do so until there is nothing left!

Not all critters can be controlled by using alcohol. Sometimes, the best thing to do with critters like slugs and snails is to simply remove them from your plant without trying to kill them using alcohol.

If you can eliminate any pests and critters without using alcohol, then try that option first before using alcohol to remove them.

Alcohol is an excellent non-toxic insecticide that can be used to kill off soft-bodied insects and pests that attack your houseplants.

Comics by AnatPlantz

Alcohol can be used as an effective herbicide to kill unwanted plants and weeds before they take over your pots!

Another benefit of spraying alcohol onto your houseplants is to control the growth of the plant. When used correctly, alcohol can speed up the plant’s growth or slow it down to extend your growing season.

Which Types Of Alcohol Can You Use On Houseplants?

Strangely enough, there are different types of alcohol, and each type can be used differently on your plants as they each have a different effect.

1. Ethanol Alcohol Slows Down Plant Growth

This is what most of us refer to as rubbing alcohol. Ethanol or ethyl alcohol is a by-product of grain and is used to make most alcoholic beverages like beer, wine, and whisky.

Vodka and whisky can be diluted and sprayed onto plants to restrict their growth, but beer and wine should never be used on any plants. The sugar content in beer and wine will encourage fungal and bacterial growth, possibly killing or damaging the plant.

Rubbing alcohol is used as a dabbing insecticide for severe pest infestations. A 5 percent ethanol solution is often sprayed onto houseplants to control their growth by delaying their maturity and extending flower production throughout the growing season.

Large flowers lose their aesthetic value quickly, and ethanol has been proven to inhibit their dying process so a small addition of an ethanol solution will keep the flower smaller but flowering longer.

You can use any clear liquor that contains at least 40% alcohol content. Vodka is a popular choice due to its neutral scent, but rum or gin will work just as well. Avoid using beer or wine as they contain sugars that promote bacterial growth.

In the medical field, Ethanol is used for a whole host of medicines, including antiseptics and disinfectants, so beware when using any form of alcohol as it is powerful, and the fumes can be overwhelming! When spraying on indoor plants, ensure that you have good ventilation to prevent yourself from becoming intoxicated!

Always test various concentrations of water-alcohol mixtures before spraying or dabbing onto your houseplants:

  • a 5 percent solution can slow down plant growth;
  • a 10 percent solution can cause the plant to become stressed,
  • a 25 percent solution can kill your houseplant!

2. Methanol Alcohol Increases Plant Growth

Methanol or wood alcohol, or methyl alcohol stimulates the growth of many cultivated plants and dramatically increases crop yields. A single spray of diluted 30 percent ethanol and methanol and 70 percent water solution can improve the development of certain plants.

If you are growing a small indoor crop to supply your family with fresh veggies, use a methanol spray solution to stimulate them. Be careful which plants you spray the solution on as it has only been successfully tested on a specific group known as the C3 plants – tomato, peas, beans, beets, and sunflower, and then only when grown in a stress-free environment.

Be cautious when watering, though, as alcohol can kill plants and damage roots, especially plants that absorb alcohol via their roots. The plant can become dehydrated and die.

3. Isopropyl Alcohol Kills Aphids

Also known as surgical spirits or rubbing alcohol. A 70 percent solution is used in antiseptics and is sold as a safe insecticide to spray on houseplants to kill soft-bodied insects like aphids, thrips, mealybugs, and whiteflies.

A 5 percent solution will also stunt plant growth, while a 25 percent solution of pure isopropyl alcohol will damage or kill the houseplant.

Again, be cautious when using isopropyl alcohol solutions as they can burn leaves in their undiluted form, particularly when the plant is exposed to bright lights.

black aphids

To prevent the plant from burning, dilute the alcohol with liquid soap and water. To avoid scarring after spraying with isopropyl alcohol, rinse each plant thoroughly with fresh water.

4. Denatured Alcohol Kills Mealybugs

Denatured alcohol is simply Ethanol containing additives or chemicals that make it smell and taste bad, such as benzene and gasoline. Humans should not consume this type of alcohol, but it is safe for use in sanitizers and moisturizers.

Denatured alcohol is excellent for spraying on your houseplants as it will safely get rid of pests like mealybugs and aphids.

Does Alcohol Spray Kill Bugs On House Plants?

Any alcohol containing Ethanol can and will kill all types of soft-bodied bugs and insects. Whether you spray the solution onto the plants as a preventative measure or simply dab alcohol onto the plant using a cotton bud as a spot treatment, this is what will happen to these unwanted pests:

  • The insect will die as the alcohol penetrates through their waxy skin (surfactant)
  • Alcohol can suck fluids out of the bodies of the insects (desiccant)

Some insects, like mealybugs, have a waterproof coating, so adding liquid soap to the alcohol spray will help the solution penetrate.

Do not spray too much alcohol onto the plants as the plant cannot absorb water if it is saturated in alcohol. If the plant cannot drink water, it will firstly suffer from stress and then die of thirst! If you accidentally overwater the houseplant with alcohol, remove the plant from the soil, wash the roots and repot into clean soil.

Your favorite houseplant will not get drunk from being sprayed with alcohol as they do not have a bloodstream like humans!

Does Alcohol Spray Kill Weeds?

Most drinking alcohols with high concentrations like vodka and even rubbing alcohol are effective weed killers. When used as a natural herbicide, alcohol can kill weeds and other unwanted plants.

You will need to be careful where you use the alcohol, as once the unwanted weeds and plants have died off, nothing else will grow in the alcohol-infused soil. Even your prized houseplants can die of thirst when their roots are soaked in alcohol!

The best time to spray alcohol onto your houseplants is at night, but if you want to use it to get rid of weeds, spray during the day and move the pot into the direct sunlight.

Organic Bug Spray Solutions

Alcohol is used in many commercial insecticides and herbicides. You can purchase these products from your local Garden center or store, or you can try and make your own organic, non-toxic, chemical-free solutions.

These are our favorite and easy to use alcohol methods to get rid of pests and bugs in your houseplants:

Alcohol To Control Mealybug Infestations On Houseplants

Mealybug infestations need to be treated immediately, or your houseplant will die! Mealybugs suck the sap out of the leaves and stems, resulting in deformed leaf growth, yellow leaves, and leaf drop.

Mealybugs are tiny white bugs that look like fuzzy white stuff on the leaves and stems of the plant and are often mistaken for fungus or mildew.

A spray is an effective way to prevent the Mealybugs from returning and attacking other houseplants. Try this solution on all your houseplants:

  • 1 cup of rubbing alcohol
  • 4 cups of water
  • 1 tablespoon of Castille liquid soap

Pour the solution into a spray bottle. Spray the entire plant. Make sure that you spray gently under the leaves and the stems. Repeat once or twice a week until the Mealybugs have all disappeared.

When dealing with severe Mealybug infestations, a diluted spray might not be strong enough. Dip a cotton swab directly into a 70 percent rubbing alcohol solution and dab the mealybugs and eggs on both sides of the leaf and the stem until both are dead. The alcohol will dissolve both the mealybugs and the egg’s protective coatings.

Alcohol To Control Scale Infestations On Houseplants

By the time that you realize your favorite houseplant is infested with scale, it may be too late to save it! Scale can attack the plant by feeding on the sap and making it very weak. The plant could eventually die, but if you do act quickly, you can save the plant as long as you are diligent in this type of pest control.

They are not hard to miss as they become immobile when feeding on the sap of the plant! Scale appears in clusters of tiny shell-like bumps on the leaves or stems of plants, similar to a sooty mold.

The easiest way to kill light-scale infestations is by dipping a cotton swab into rubbing alcohol and dabbing it onto the scale. The process is tedious, but this method is effective. Prune disfigured leaves, branches, and twigs from the plant to prevent the scale from spreading.

More severe infestations require more drastic solutions:

  • 1 cup rubbing alcohol
  • 4 cups water
  • 1 tablespoon insecticidal soap

Pour all the solutions ingredients into a spray bottle and spray gently over the scale. Repeat every three days for two weeks until all the scale is gone.

Here is an article I wrote about 9 ways to prevent scale infestation on houseplants.

Alcohol To Control Aphid Infestations On Houseplants

Aphids live in huge colonies on the underside of leaves and feed on the sap causing deformed and yellow leaves.

Ethanol is the most effective type of alcohol to use for eradicating aphids. Isopropyl or rubbing alcohol is an excellent second best but is not as effective.

To make an effective insecticide spray, mix equal parts water and alcohol into a spray bottle and spray lightly over the plant – don’t drown it!

Another effective solution is:

  • 2 cups alcohol
  • 5 cups water
  • 1 tablespoon liquid soap

Gently mix all the solutions ingredients in a spray bottle and spray as needed. The soap ensures the solution sticks to the aphids’ bodies, absorbing more of the alcohol.

Alcohol To Control Mite Infestations On Houseplants

Mites are tiny and are almost invisible to the naked eye! The easiest way to identify them is by the wispy white threads of webbing on the leaves of your houseplant or by the damage to your plants.

Mites feed on your plants by sucking out the sap. This will make the plants shrivel up and become curled and discolored. If you don’t get rid of them quickly, they will kill your plant!

mite living on plants

To make sure that mites are to blame for destroying your plants, place a sheet of white paper under a leaf. Gently pat the leaf, and the mites should fall onto the paper.

You can always check the underside of the leaves using a magnifying glass. If mites live on your plants, search for what looks like grains of ground black pepper, red specks, or brown dots – these are mites!

The best and most effective way to get rid of these destructive pests is by using Ethanol or rubbing alcohol. Dab some onto a cotton swab and gently wipe over the infected leaf. Leave for a few hours, then use a damp cloth to wipe off the dead mites.

For sensitive plants, use the following method:

  • 1 cup alcohol
  • 3 cups water

Pour all the solutions ingredients into a spray bottle and spray over the infected areas. Leave for a few hours, then remove wipe down with a damp cloth to remove the mites.

Alcohol To Control Whitefly Infestations On Houseplants

Whitefly is relatively easy to identify as they attack new growth on your houseplants. The leaves on the plant will feel sticky because of the bug secretions. Further damage could include yellow leaves, leaves falling off the stem, and stunted plant growth.

whitefly on leaves

Whiteflies look similar to tiny moths, while their larvae are transparent and flat. When the larvae hatch, they will feed on the plant’s sap. Thankfully, whiteflies are not too destructive and are easy to control.

Use this method to get rid of Whitefly and to prevent them from returning:

  • 2 cups rubbing alcohol
  • 5 cups water
  • 1 tablespoon liquid soap

Combine the solution’s ingredients and pour into a spray bottle. Spray gently over both sides of each leaf. Spray twice a day for three days. Remove the dead bugs from the leaves using a damp cloth.

Alcohol To Control Fungus Gnat Infestations On Houseplants

You will know If you have a Fungus gnat infestation because of the tiny flies hovering below your houseplants!

Fungus gnat larvae feed on plant roots while the adults feed on fungi found in the soil. While these pests are not harmful to humans, they can cause stunted and slow growth in your plants.

Try this solution to get rid of Fungus gnats effectively:

  • 1 cup rubbing alcohol
  • 4 cups water

Pour the solution’s ingredients into a spray bottle and spray gently over the plant and the soil every three days. Continue with this treatment for three weeks until there is no sign of Fungus gnats.


The most effective, non-toxic way to get rid of pests is to spray them with alcohol. Always test your solutions on a few leaves and leave for at least five days before spraying over the entire plant. Use PPE when working with alcohol to prevent skin irritations.

Alcohol is not only effective in killing these unwanted pests, but it does have other benefits too. Alcohol can be used to slow down or speed up plant growth, kill weeds or even revive droopy flowers!

There is always a caution that comes with using alcohol other than as an insecticide, though, so be wary of how much you use and how often as alcohol can kill or burn your much-loved and well-cared houseplants!

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Anat Goldberg

Hi! My name is Anat and I have lived all my life in the countryside. I grew on a farm in Northern Italy and from an early age, I took care of the animals on the farm and the family garden. Over the years I have developed a growing passion for organic cultivation and pest control.

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