Does Roundup Kill Ants? How To Get Rid Of Ants In The Garden [7 Ways]

Ants have been cutified into cartoons with their own television shows, full-length animated movies, even served as salad toppings. However, at the end of the day, many of us want to know the best ways to kill them. Can a widely-used weed killer like Roundup do that?

Roundup does not kill ants. On the other hand, another product from the same family called Roundup for Lawns Bug Destroyer does get rid of ants effectively. Other solutions include:

  1. Ant killer poison bait
  2. Borax and sugar solution with cotton balls
  3. Baking soda and icing sugar solution
  4. Boiling water and salt solution
  5. Vinegar and dishwashing liquid solution
  6. White vinegar and water spray
  7. Diatomaceous earth

But wait. Ants are said to be loyal, industrious, thrifty, trustworthy, and brave. Why do we hate ants so much? Let me summarize.

Are Ants Dangerous Or Just a Nuisance?

Except for scientists, entomologists, and ant farm sellers, many people simply don’t like ants. The most common reasons are that some ants species give painful bites, pose potential health risks, destroy crops and property, and are aggressive invaders.

They’re super-invaders: They’re incredibly invasive. In fact, ants are ranked up there among the world’s worst invaders of all time, creating huge super-colonies that are thousands of miles wide. There are at least 14,000 different ant species, and they’re survivors for the last 80 million years, surviving when dinosaurs cannot.

They’re very destructive: Ants destroy infrastructure, consume crops, and demolish entire native plant and animal ecosystems in Europe, the USA, and Japan. A report says that every year in the USA, fire ants cost more than £3 billion in damages including millions of dollars in medical and veterinary costs.

PRO TIP: According to a report from Iowa State University, humans are not earth’s most dominant life form — ants are. One estimate says the weight of all ants and the weight of all humans on earth are equal.

And that’s not all.

They’re painful health risks: The bite of some ants and might create health risks. In fact, an ant bite can cause itching, intense pain, urticaria (hives), pustules, or blisters, and for some people, an allergic reaction called anaphylactic shock, which can be life-threatening.

We’re not safe, even indoors: Indoors, ants can track diseases with their sticky, hairy feet. Since they get into our food easily, they can also bring dirt, germs, or bacteria each step of their six feet. And we’re not talking about one ant or a few — there’s always an army of them.

7 Ways To Kill Ants: Chemical, Organic and DIY [2 Bonus]

Here are 8 solutions that many gardeners have tried. Some of these solutions are more on the chemical side (and often more effective) while others are more organic, which is the way to go if the ants are close to edible plants.

Since Roundup kills almost all plants, many ask if it also kills ant colonies. No, it doesn’t; the worst effect of Roundup on ants is that they stop digging. However, there’s another Roundup product designed to kill ants and other bugs. Let me explain.

1 – Roundup For Lawns Bug Destroyer

Roundup was introduced by Monsanto in 1974 as a weed killer (herbicide). It kills plants — except genetically modified (GM) crops that resist herbicides. However, Roundup is not an insecticide and therefore doesn’t kill ants. But there’s good news. 

For up to three months, Roundup® For Lawns Bug Destroyer is said to kill 100+ insects, ants, grubs, spiders, fleas, ticks, fire ants, sod webworms, and cutworms above-ground and underground.

If this doesn’t work for you, you probably didn’t water the ground — that’s what you need to do to activate its active ingredients. In some cases, you might need to reapply, such as when it rains and the poison doesn’t last.

Get Rid Of Plants – Infographic

How To Use It?

Here a quick overview on how to use the Roundup for lawn bug Destroyer:

  1. Determine the total area of your entire lawn or garden to calculate how much product you would need to use. The standard amount needed for the proper application of this product is 4 lbs (around 1.8 kg) per 1,000 sq. ft. (92.90 sq. m.) of land.
  2. Directly apply the product evenly on dry grass early in the spring or during summer.
  3. Start application from the outer border of the area and then fill in the middle by going through rows or columns. Do this by using either a broadcast/rotary or drop spreader. Make sure to set your spreader’s dial according to the package instructions – 3 3/4 and 4 3/2 respectively. If some of the product lands on the driveway or sidewalk, sweep it back into the area you want to treat.
  4. Immediately water over the areas you have applied the product to using a sprinkler or garden hose. Avoid over-saturating the land with water.
  5. Finally, wash your hands thoroughly after application and let it dry completely before allowing pets and other people in the treated area.

What Do I Think Of It?

Because it’s from a trusted brand, I went ahead and bought it to try it out the first time I had mounds of ants springing up in the garden. It was easy to apply and cheap as well. Within a week of application, ants were nowhere in sight!

The fact that it effectively got rid of most of the ants taking shelter around my flower beds is a massive plus as well because it didn’t negatively affect any of my babies. Just make sure you don’t apply the product near flowers that bees regularly visit as they may die along with the ants too. Never use more than instructed either as you could kill your grass.

Unfortunately, it wears off quite easily with even just a moderate amount of rainfall after a few months. Add that to the fact that it can only be applied to the same area once a year, I just don’t think it’s actually that cost-efficient.

There’s a high chance of killing off all of the lovely blooming plants I have cultivated throughout the years if I ever tried reapplying within the first year of initial application. So I didn’t want to risk it. The ants came back in less than half the year though. It does the job but not for very long.

2. Ant Killer Bait

We know that the world of ants includes 11 subfamilies, 297 types, and about 8,800 species identified so far. The most painful bites are said to be from fire ants.

You can check out a fire ant killer such as the below on Amazon.

An alternative, in case you’re plagued by both weeds and ants, you can find products that kill both weeds and ants, such as the Scotts Turf builder below.

The Scotts product takes around a few weeks to be effective. However, its efficacy is pretty high and it is able to get rid of ants and other insects responsabile to eat your grass. After the first application I suggest reapplying after 7 weeks.

How To Use It?

Here a quick step by step guide on the best way to use such product:

  1. The manufacturer produced a mobile app, it is quite useful to understand how much product you need. If not very techy savy you can use the stadards amounts: 3.33 lbs (1.51 kg) per 1,000 sq. ft. (92.90 sq. m.) of land.
  2. After mowing for the third time during the spring season, directly apply the product evenly on dry grass. Keep in mind that this can also be used in the fall as long as the ground is not dormant and temperatures have consistently been 60-90°F (16-32°C) several days before application.
  3. Start application from the outer border of the area and then fill in the middle by going through rows or columns. Do this by using either a broadcast rotary or drop spreader. Make sure to set your spreader’s dial according to the package instructions – 4 1/4 and 8 1/2 respectively. If some of the product lands on the driveway or sidewalk, sweep it back into the area you want to treat.
  4. Immediately water over the areas you have applied the product to using a sprinkler or garden hose. Avoid over-saturating the land with water.
  5. Finally, wash your hands thoroughly after application and let it dry completely before allowing pets and other people in the treated area.

What Do I Think Of It?

I’d say that our fire ant problems were solved using this product without much hassle or issues whatsoever. In just a few days after application, the ant hills visibly reduced in number.

Before buying it, I of course checked for the experiences and comments of previous product users. Very few had issues from using it. What’s more, those issues that occurred seemed to have been due to error in application like watering too much after spreading the product onto the ground. This of course would result in washing out the product completely off your lawn.

Other issues seem to be related to suboptimal temperatures during application as well as over application of the product. Here a warning: being too generous during product application is not good! This can cause not only the death of the ants and weeds but also the healthy grass in their yards.

Personally, I’ve never encountered any problem with this product. So as long as you carefully read and follow the instructions on the package for proper application, I’d say you’re all good. But if you do encounter problems even when you have followed everything to a tee, their customer service seems pretty responsive so go ahead and contact them.

The only thing worth noting is the price. I have bought this product twice already but on my second time it was way cheaper. You might need to check periodically to find the best deal.

The best baits that serve as ant poison comprise two parts: food as well as one part slow-acting poison in the food. These baits are so designed that worker ants collect them and bring them back into their colonies, where other ants, including the queen ant, can eat them.

3. Borax + Sugar

Mix borax with sugar. Then, gradually add water until you create a paste. If you add too much water, the paste is too watery and the ants can’t carry that into their colony.

You can gradually add a bit more borax and sugar till you get a paste-like consistency. This is easier for the ants to transport. Ants are attracted to the sugar. When the borax gets into the ants’ bodies, it destroys their digestive systems.

But be careful: too much sugar and the solution won’t work as fast. Too much borax and the ants may notice the poison and ignore it.

You can order borax online in powder form (here on this one on Amazon).

4. Baking Soda + Icing Sugar

Baking soda is less alkaline than borax, but many of our gardener friends swear that a paste of baking soda, sugar, and water that is left near ant mounds or ant holes works very well. Worker ants are attracted to the sugar and carry everything — in bits and pieces, of course — into their underground colony.

Icing sugar is recommended because it is easier to turn into paste compared to ordinary granulated sugar. You can try out a pack of icing sugar or organic powdered sugar.

However, in urgent cases, drop some regular sugar into your blender or grinder and turn it into powder. Then, use it instead of icing sugar.

Cool Fact One of the largest ant colonies in the world was found in Argentina, and it’s more than 3,700 miles wide.

5. DIY: Boiling Water + Salt

One of the cheapest natural solutions to an ant infestation is table salt. However, this solution is not recommended as this can seriously affect the plants nearby.

Before you do that, identify where the ant mounds are, or where the ant holes can be seen on the soil. Also, if you need the salt to dissolve really fast, use a blender or grinder and turn the salt into dust before boiling it.

When the saltwater boils, pour it right into the ant mound or ant holes. Continue pouring until the saltwater runs out of the hole. That means the colony is totally flooded. If you need more, simply boil another batch and repeat.

While this is probably one of the easiest and lowest-cost natural solutions to solve a serious ant problem, think many times before you use it. The reason? The salt stays in the soil for years. Nothing grows on salted soil — not grass, not crops, not flowers — absolutely nothing. This could be a problem later, such is if and when you sell the property.

PRO TIP: Boiling water and salt is my favourite way to remove annoying weeds that grow in front of my house. Simple and effective. Be sure to repeat this hot bath to the weeds multiple times in a row as the water tends to cool down without totally killing the plant roots.

6. DIY: Vinegar + Dishwashing Liquid

This strategy is for the soft-hearted who can’t bear the thought of killing little ants. This solution only keeps ants away from your house, farm, or garden. Here’s how you do it.

Mix equal amounts of tap water, white vinegar, and dishwashing liquid. Shake well in a spray bottle,ready for use anytime you see ants marching into your home or potted plants.

Trace the marching line to any crack, hole, door, window, or entry point. Then spray all along that line, but more so in the entry points.

If you can go outside your home and trace the ant line into the soil where you see ant mounds or ant holes, spray liberally.

Since this solution doesn’t kill ants, you may need to re-spray or use a larger spray bottle.

If you have a very serious case of an ant infestation — huge ant colonies are all over your lawn, for instance — pour your home-made ant repellent into a sprayer and spray your lawn.

If you’re out of dishwashing liquid, no worries. A number of our savvy indoor gardener friends swear that a half and half mixture of tap water and white vinegar works just as well. If you try it out, tell me the results. I’d love to hear about it.

PRO TIP: Vinegar may be too strong for the leaves of some delicate plants.Test a small area for a day. Observe if plants show any burn marks on the plants.

7. Diatomaceous Earth

Diatomaceous earth looks like a baking powder but it’s neither earth nor soil. Actually, it’s fossilized marine phytoplankton, so it’s fully organic. All you need to do is to apply it on anthills and ant trails.

If you haven’t tried it before, order a pack of diatomaceous earth such as this one from Amazon and see how well it works for your ant problem.

However, if you’re amidst a huge, spreading ant colony (ant mounts or ant holes are all over your garden or around your house, for instance) that’s giving you panic attacks, go for a pail of diatomaceous earth such as this one, also on Amazon.

I’ve had mixed reports about the effectiveness of diatomaceous earth in repelling ants. Some gardeners say it works, some say it doesn’t. This may be due to the type of ant, the type of soil, soil moisture, or soil temperature, I don’t know. If you can, share with me what you know for sure.

There are many other suggestions such as chalk, cream of wheat, cornmeal, and so on. They’re common knowledge, but here’s a bonus. Or two.

BONUS 1: Companion Planting

Many of us are against killing ants. At the same time, many of us are also concerned about the environment, so we don’t want to pour salt or chemicals into the soil. That stuff can get into waterways, contaminate the environment, even affect other plants and animals.

To avoid ants, we can keep food and food garbage sealed away, keep dining areas, kitchen sinks, picnic grounds, and always clean snack areas. In short, we can make sure that nothing attracts ants.

What if that’s not enough?

No worries. One lovely solution is companion planting in our kitchen herbs, potted porch plants, and indoor plants. Companion plants are natural ant repellents. In short, ants hate them, so they’ll stay away from your indoor gardens.

Here are some plants that gardeners say are effective in keeping away (but not killing) ants: basil, chives, citronella grass, catnip, chrysanthemums, garlic, rosemary, lavender, marigold, mint, petunias, peppermint, rosemary, thyme, and tansy.

BONUS 2: Plants-based Scents

The following suggestions are ant-repellents, not ant-killers.

Hot peppers: Blend into powder some cayenne or black pepper (or both), and pour this into ant holes or mounds. You can also dilute this in water before you pour – 2 tablespoons per 1 cup of water will do.

Essential oils: The strong scents of peppermint, citrus, eucalyptus, or cinnamon oil can repel ants. By the way, please note that one study found that cinnamon oil can kill ants. When the scents wear off, reapply.

Coffee grounds: If you love coffee (not the instant kind), coffee grounds repel ants (and cats, too). At the same time, your potting soil or garden soil will be enriched by magnesium, potassium, and phosphorus.

Citrus and cucumber: Ants feed on fungi that die when exposed to cucumber and citrus peels. You can also use household cleaners that are scented with cucumber or citrus. Choose products with real citrus or cucumber oils – synthetic scents won’t work.

PRO TIP: Keep essential oils out of the reach of pets and children. Also, If you have pets or kids in the house, don’t use pepper oils – the capsaicin in these oils can irritate noses and throats.


And that’s it – you’ve just completed a summary of how ants affect us, and how we can protect ourselves from them. Before you go: here’s a quick list of takeaways.

Ants are pests: Despite their beneficial role in soil ecosystems and scientific research, ants are invasive, destructive, and present painful health risks to humans.

There are two types of Roundup: Roundup weed killer does not kill ants. However, Roundup For Lawns Bug Killer kills ants and other bugs, insects, and worms.

Target ant colonies, not ants: You can kill ants by using borax or baking soda with sugar; as well as with a mix of boiling water, salt or vinegar, and dishwashing liquid.

Repel without killing: You can repel ants with diatomaceous earth, companion plants, essential plant oils, plant-based scents, or used coffee grounds.

I hope that this article helps you as much as it has helped me and my friends. If you have experiences to share, or if you have questions about roundup and killing or repelling ants, please let me know. I’d love to hear from you. is part of the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites like mine to earn advertising fees by promoting good quality products. I may receive a small commission when you buy through links on my website.


“Massive Yet Grossly Underestimated Global Costs Of Invasive Insects” by C. J. A. Bradsaw et al in Nature Communications

“The Causes and Consequences of Ant Invasions” by D. A. Holway et al in Annual Review of Ecology and Systematics

“Super Ant Colony Hits Australia” by BBC News

“Ants Are Ecologically Beneficial?” by Iowa State University (ISU) Extension and Outreach

“Anaphylaxis – Symptoms and Causes” by Mayo Clinic

“Roundup Caused Lab Ants To Stop Digging” by Eli Chen in St. Louis Public Radio

“Pear Salad with Chiangbai Ants” by D. G. Gordpon in The Eat A Bug Cookbook in Epicurious

“Palatability Of Glyphosate In Ants: A Field Experiment Reveals Broad Acceptance Of Highly Polluted Solutions In A Mediterranean Ant” by F. Frizzi et al in Environmental Science and Pollution Research

The Ants by B. Hölldobler and E.O. Wilson, Harvard University Press

“Signaling Science: What Household Solutions Repel Ants?” from Scientific American

“10 Cool Facts About Ants” by National Geographic Kids

“What’s the difference between Roundup and Roundup For Lawns?” by K. Frank and A. Hathaway, Michigan State University Extension (MSU)

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