The Best Ant Killer for Outdoors (No Ants in Your Plants)

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Last Updated on February 23, 2023 by Griselda M.

Ants are becoming a problem globally as more and more species are moved out of their native ranges and become pests. Finding the best ant killer for outdoors use allows you to control both native, and more often exotic ants that are competing with you for living space. Understanding the biology of the problem helps us understand how to control the problem.

I will list a few options here that I use, as well as a few chemical options. I would like to caution that the majority of chemical options are, in my opinion, more dangerous than ants, so we will explore a few gentle alternatives to chemical options – things that can put money in your pocket, rather than cancer in your genes.

What are Ants?

You may think I am being an idiot asking this question, but it is important to differentiate between ants and termites. Ants are small largely flightless social wasps that have a female-dominated society and can range from insectivorous to vegetarian in nature; termites are vegetarian.

They look a bit similar in some ways, but the big difference is termites have male and female workers and ants have only female workers. Both can be pests, and both are invasive species around the world, so when we decide we need to get rid of ants, it is probably important to make sure we have ants, and not termites.

There are a really large number of species of ants – if you take a look at this list, it shows the 792 species of ants known to be present in the USA alone. Ants are incredibly diverse in their feeding strategies, with some being vegetarians, some being omnivores and some being predators. There are even some that are specialist hunters of mushrooms!

There are, as we have just stated, many different types of ants. All of them tend to have biting mouth parts, which means that, if they move into our lawns and gardens, they can make things unpleasant. Some sting as well. When I was a toddler I remember my parents moving to a research station in the semi-desert, and, as soon as we arrived at the new house, carnivorous ants swarmed up my legs, so I rolled and rolled and fell off a wall breaking my collar bone. Biting ants are a pain – in my case, literally a pain in the neck to this day.

How Do We Control Ants Outdoors?

In my opinion, there is a logical path we follow in deciding how to kill ants outdoors. This is a different path from the one we use indoors. For indoor ant problems, poisons, and poison baits are often the most practical means of getting rid of ants. For outdoor ants the process is different.

Identify what the ants are eating

Ants that farm aphids/mealy bugs/scale

I have a recurring problem with little black ants that are attracted to my citrus plants, where they grow mealy bugs and scale. I do not wish to spray my citrus trees with man-made poisons but have learned that if I spray the mealy bug with neem oil, it kills this, and then the ants have nothing to farm and die or leave. If your ant problem is a type of ant that is farming aphids/mealy bugs/scale on your plants, kill the aphids/mealy bugs/scale with neem oil (which is natural and not very toxic). The neem oil only kills insects that are growing, so it will not actually kill the ants – it just kills their food.

Ants that are eating leaves, or hunt insects and other protein sources

If your ants are not feeding on aphids then they could be ants that are cutting leaves – in this case you will see them cutting up leaves. These ants are more difficult to get rid of.

If your ants seem to be predators, catching other insects and hunting, you will also have to work out a strategy.

The Best Natural Ant Killer for Outdoors – Chickens

To control the above two types of ants, I recommend chickens. Chickens are very fond of ants -they will find little black ant nests and peck at the ants for an entire day, eating any foragers that emerge and if they can get to the nest, they will scratch it out and eat the larvae, queen and all the workers. Chickens can even eat fire ants, probably one of the worst types of ants around.

Japanese bantams are a particularly small, relatively quiet chicken breed that will hardly damage your plants, but they will trundle around all day digging up ants and worms and turning a problem into eggs and very small chickens (if you decide to eat some). If you can free-range your chickens, Japanese bantams, or any bantam chicken really are excellent ant hunters. I have hardly any ants left in my garden, and I have a lot of bantams.

You can let the chickens free range if your dogs and neighbors are tame.

Chickens as an ant lawn killer

You can use a chicken tractor such as this one. With this system you move it around the lawn, making sure to feed the chickens a bit and give them water. They will trim your lawn, eat ants, eat crickets, hoppers, snails, worms, and even mites, and at the end of it, you will have a fertilized lawn that is free of pests, and a bunch of eggs.

Homegrown eggs are produced by chickens that eat a balanced diet of grains and weeds, leaves, bugs, ants, worms, and a range of other things (puffballs). This means the eggs produced are packed with lipids – fats – that enhance the functioning of your body. Commercial eggs have far poorer lipid profiles, hence once you start producing your own eggs, you will never want a shop egg again. Imagine – now your lawn, a source of constant irritation, becomes a source of constant health!

If the Above Natural Methods do Not Work, We Progress to Chemical Means

Borax

Borax is a chemical that is generally regarded as acceptable in organic gardening. In some cases, it can be beneficial to actually add this in small quantities to the soil. For me, in terms of choosing chemical treatments for any pest, I try to look for the ones that have the least harm, or risk to myself, my loved ones, and my environment. In this regard, a Borax-based treatment that kills ants is desirable as a first-choice chemical control and if it does get into my soil, the chances are it is doing a good thing, not a bad thing.

The best outdoor ant traps using Borax – Terro liquid ant bait

This is a borax-based ant bait. It is available in an outdoor-optimized format here. These baits are quite simple – they consist of an attractant solution – typically sugar of some sort – and borax. The forager/worker ants discover this and they take it back to the colony where it is fed to the queen and the larvae. The action is relatively slow (so the workers do not die too quickly) meaning that a decent payload of bait can be taken to the queen.

The volume of these bait stations is quite large – and this means that you should be able to use one or two traps to take down a relatively large colony. A trick I have learned in the past is to keep old empty traps and mark these with an X. Put a bit of honey in these traps and the ants will come and get used to feeding at that station. Let them feed for three days, and really build up a strong line of foragers going to the trap. Swop the “honey trap” out with the new poison trap that is baited with the correct bait. The ants now have become really used to feeding at this site and they will take a huge load of the poison back and wipe their colony out quickly.

Because of the mode of action of Borax on ants, there is no real way the ants can become resistant to it. It should always work, and consequently, it is my preferred method for getting rid of ant problems that cannot be controlled with chickens. I personally have never found a problem that required anything more drastic than this, hence I am sure if you apply yourself you can use chickens and borax baits such as Terro Liquid Ant Bait to solve any problems you have.

More toxic chemical baits

However, if you need to use another method of chemical control, some poisons have been developed that incorporate various synthetic pesticides. These can be effective if you need to achieve a quick knockdown. It is important with such substances, that are inherently toxic, that you read the fine print carefully so that you know exactly what you are exposing yourself to, and how to limit the negative impacts of these chemicals on yourself, loved ones, pets, livestock, and the environment in general.

Best ant killer for lawns – Amdro home perimeter

The Amdro Home Perimeter outdoor ant killer contains hydramethylnon. This is a metabolic disruptor for ants, and it works slowly enough that the ants can forage, find the granules, and return them to the nest where they will kill the queen, and younger ants, resulting in the death of the ant colony.

Hydramethylnon is entirely degraded in the guts of ruminants (cows etc.) There is some worry about it being a possible carcinogen if it penetrates groundwater – if you have a large lawn, plan to use this, and drink groundwater from a well on your property, consider this a negative. Other than that, from a biochemical overview of what I can read, it appears to not be a particularly horrible poison.

The application appears to be simple – scatter the pellets and let the ants destroy themselves.

Ortho Orthene outdoor ant killer

Ortho Orthene Outdoor Ant Killer would be for me a choice of last resort. The active ingredient, Acephate, is an organophosphate poison. These work by inhibiting the way certain neurotransmitters are broken down, resulting in nerve poisoning and death. In insects, the effects are more acute than in humans, but you can easily kill yourself with this poison if you consume or absorb enough through your skin. Naturally, if you apply it to a lawn, and children were to later play on that lawn, fall, and graze themselves, there is a definite risk of exposure. It is a relatively nasty chemical. There is not a lot of data to suggest whether it does cause cancer, but it definitely damages sperm cells.

It is also highly toxic to bees, and as a beekeeper, I really would prefer not to see poisons such as this thrown on lawns where it will fall on flowers and get back into hives.

If you have a really really big problem with fire ants and need to quickly break the back of an infestation, I would recommend that you could consider using this poison. I would also try to exclude pets, kids, and adults from the treated area for a week or two after application. After good rains, the concentration of poison on the surface will decrease as it washes into the soil due to its high solubility in water.

Ortho Home Defense Max Insect Killer granules

Ortho Home defense is an insect killer super pack. It contains the active ingredient Bifenthrin which is a synthetic pyrethroid. Pyrethroids are based on the chemistry of a natural compound found in certain daisies (Pyrethrum). This is a somewhat less toxic chemical overall than the one in the previous product, and I would probably choose this over the previous if I had to use a chemical pesticide.

This is a pretty indiscriminate pesticide and will kill everything in the area you treat. In this regard, I would be quite worried about it, as it creates a vacuum of insects – and vacuums always get filled by irritating things. It will kill centipedes and other natural predators that mind their own business in the compost layer of your lawn quietly eating all sorts of pests. Now you kill these beneficial insects, spiders, and other predators, and you create an environment just waiting to be invaded by new pests.

This product would be, for me, much like the previous, a last resort. If I cannot control a big problem with safer means (chickens, failing that Borax), I would resort to this. It suggests that after you water the poison into the lawns and allow the lawn to dry, the area is safe to use. I would wait three days – chemical companies are always overly optimistic as to how safe their toxic chemicals are. Use the precautionary principle.

Bayer Advanced Ant Killer Plus

This product contains both beta – Cyfluthrin and Imidacloprid.  This is an insect, flea, tick and mite, spider, and everything else killer. Bayer has a long history of being quite good at extermination, and this carries through quite well into this product. Imidacloprid is a neo-nicotinoid – in other words, a synthetic more toxic version of nicotine and Clyfluthrin is a synthetic pyrethroid. In this way, we manage to combine two families of poisons that are really toxic to honeybees into one product to spray onto lawns.

If you need a rather drastic type of final solution to killing ants in your lawn, this is probably a functional option. I am, as you can detect from my cynical tone of writing, not fond of these chemical solutions, and this particular one really is rather drastic. I have had beehives poisoned by Imidacloprid and just do not like this chemical at all. If you do decide to use this product, please check that there are no flowering clover, dandelions, and other small flowers nestled in your lawn. This will minimize the impact you will have on your pollinators in the area due to the application of pesticides.

Verdict the Best Ant Killer for Outdoors

A lawn or any other part of our garden is supposed to be a safe space. We do not want to have insects that bite us, such as fire ants in the area, and we also do not wish to poison ourselves while walking through a toxic wasteland that is insect free but covered in chemicals that poison us, give us cancer, and kill our environment.

In this regard, the most sustainable, useful, and cool way of controlling ants is with chickens. You actually get eggs out of it, and a healthier environment. If you cannot use chickens, then use a Borax-based bait that kills the ant nests. There is actually a need for boron in many soils, and the chances are that using these baits will in some way enhance your soil fertility.

If you cannot solve these problems in the above logical, low-risk, sensible ways, you can resort to using more toxic man-made chemicals to control the problem. This is in many ways something you will probably come to regret in the future, but, if you have an extreme emergency, consider these methods, and then, once you have controlled the problem, use Borax-based baits and chickens to keep the situation under control.

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