Tackling Tiny Invaders: Will Neem Oil Kill Ants?

If you’ve ever spotted ants crawling all over your garden plants, you may be wondering if they’re harmful and if so, what to do to get rid of them.

In most cases, seeing a few ants in your garden is not a reason for concern, unless it’s the tropical leaf-cutting ant, but they have a limited demographic – indigenous to South and Central America, with only four states in the US known to have them: Arizona, Texas, Louisiana, and Southern California.

Do other varieties of ants pose a threat to garden plants?

Although most ants do not eat the foliage of your plants, there are a few reasons you might not want ants in your garden.

Ants protect aphids – Ants actually farm aphids, protecting them from their natural predators, herding them to the juiciest parts of leaves and watching over them, and even carrying them back to their anthill at night for protection. The reason for this is the “honeydew” that aphids secrete after munching on leaves. Ants feed on this sugary substance. So, if you notice a lot of ants, look closer – you may have an aphid problem.
Extensive ant tunnels can damage the roots of your plants – Although a small number of ant tunnels will aerate your soil, and can be beneficial for your plants, an infestation of ants can create a massive tunnel system, which can weaken the root system of your plants, damaging them beneath the surface.
Some ants can deliver a nasty sting – If you’ve ever been stung by a fire ant, you know what I’m talking about! All ants can bite, but fire ants, harvester ants, and oak ants have tiny stingers which deliver venom, forming painful blisters on the affected skin. That’s not the kind of experience you want while working in your garden.

So, how do you get rid of ants in the garden? If you’re an organic gardener like me, you’ll turn to a natural solution, such as neem oil.

Below I will cover the effectiveness of neem oil to kill and repel ants, how to prepare and apply a homemade solution, as well as offering alternate, natural remedies for eliminating an ant problem in your garden.

Does Neem Oil Kill Ants?

Neem oil can be used to kill and repel over 170 types of insects, including all varieties of ants.

Neem oil works in two different ways:

First, when applied as a diluted foliar spray, neem oil works on direct contact with the pest, coating their body with oil and blocking their airways, often suffocating small insects immediately.
Also, neem oil contains the compound, Azadirachtin, which, when ingested by ants, disorients them, and disrupts their biological functions, such as feeding, and reproduction.

What is Neem Oil?

Neem oil is an organic, biodegradable pesticide made from pressing the seeds of the neem tree, which grows in Southeast Asia and parts of Africa. It is non-toxic and will not harm people, pets, birds, or beneficial insects, if used as directed on the package. It is safe to use on fruits and vegetables, as well as flowers.

Does Neem Oil Kill Ant Eggs?

Not exactly. It takes 3 – 4 weeks for ant eggs to hatch into larvae. Neem oil kills either by suffocation, or by ingestion. Therefore, the eggs themselves may be able to hatch, but an application of neem oil will kill the larvae on contact by smothering their airways.

Also, with repeated applications of neem oil, ants will be unable to lay eggs, as azadirachtin disrupts their hormonal system.

Does Neem Oil Prevent Ants?

In a roundabout fashion, neem oil can deter ants, even the most common varieties that don’t eat the leaves. Neem oil has a very strong, sulfuric smell, and a bitter taste that aphids do not like – and remember, your ants are likely there for the aphids, not the leaves themselves.

Used as a soil drench, the roots of the plants take up the neem oil into the leaves’ cellular structure, affecting the flavor of the leaves, making the leaves less appealing to aphids, and thereby reducing the number of ants.

If you’re in an area that has leaf cutter ants, the taste of the neem oil in the leaves after a soil drench may repel them.

How to Mix Neem Oil for Ants?

The most economic way to use neem oil in your garden is to make the solution yourself, using 100% pure, cold-pressed neem oil. This method has the added benefit of knowing exactly what’s in your solution and controlling the concentration.

To begin, assess your needs. Are you covering a large area, or just a few plants? It’s important to only mix enough neem oil solution for immediate usage, as the active component will deteriorate quickly once mixed with other ingredients.

For every quart of solution needed, start with 4 cups of water (preferably not cold). Add 1 teaspoon of neem oil, and a drop of liquid soap. Shake vigorously, and transfer to either a spray bottle, or, for a larger area, use a garden sprayer.

How to Apply Neem Oil to Kill Ants?

You can apply neem oil by spraying the leaves, stems, and stalk of your plant thoroughly, or by using a soil drench at the plant’s roots. If you see the anthill in your garden, you can pour the neem oil solution directly into the anthill. If doing the latter, be ready to step away as the ants come pouring out, especially if you’re dealing with fire ants.

It usually takes several applications for any of these methods before your ants will be eradicated.

When spraying neem oil on your plants, be sure to dilute the oil, and only spray once the sun goes down. This will protect your plants against foliage burn, and also protect pollinators from accidental exposure, since they’re only active in daylight hours. Bees and butterflies can suffocate if neem oil clogs their airways.

How Often to Spray Neem Oil for Ants?

You can spray neem oil on plants every 3 – 4 days. More often than that, and you’ll risk damaging the plants. Always check your plant’s foliage for signs of “burn” (dry, white or tan patches) before reapplying neem oil. If you have foliage burn, increase the time between applications.

If using a soil drench at the plant’s roots, you should apply every 2 – 3 weeks. Azadirachtin can stay active in the soil for nearly 3 weeks, so drenching more often than that may be unnecessary.

When pouring neem oil solution on anthills – as long as you’re not getting the solution on any plants you value, it’s fine to reapply as often as you like. Neem oil can kill ants on contact, if they’re thoroughly immersed in it.

How Long Does Neem Oil Take to Kill Ants?

If the ants are small enough, and the neem oil is applied thoroughly enough, some ants might die of suffocation immediately. For larger ants that have been less saturated, it may take time for the azadirachtin to work its magic. Within 3 – 5 days, ants that have ingested the compound will become unable to feed, breed, or lay eggs, which will break the cycle. Simply repeat applications over the next few weeks and you should win the battle.

Can Neem Oil Hurt My Plants?

If applied properly, neem oil will not hurt your plants, with a few exceptions.

Never use neem oil on plants with delicate, wispy foliage, such as many herbs.
Never use neem oil on plants that are stressed from recent transplanting, or from over/under-watering.
Never use neem oil in the bright sunlight. It’s best to wait until dusk.

Are There Any Alternative Ways to Get Rid of Ants in the Garden?

It’s always good to have more than one weapon in your arsenal! Here are a few more organic ways to get rid of the ants in your garden.

Diatomaceous earth – a powdery substance made from the fossilized remains of tiny, aquatic organisms, which kills ants by getting beneath their exoskeletons and drying out their bodily fluids.
Insecticidal soap – sprayed directly on ants, it can be lethal, but must be reapplied often.
Borax combined with powdered sugar – a homemade ant bait that gets real results! Simply mix one part borax to three parts powdered sugar and add just enough water to make a paste. Fill bottlecaps or other small containers with the mixture and set out in the area you’ve noticed ants. (Take care not to place these where children or pets may ingest them) Borax, once ingested by ants, is lethal within a few days.
Use citrus essential oils – orange and lemon essential oils are toxic to ants. Make your own spray by combining 3 Tablespoons orange essential oil, 1 teaspoons honey, a squirt of liquid dish soap, and a quart of warm water. Shake well and spray your plants and soil thoroughly. Be aware that citrus essential oils are toxic to pets, as well.
Introduce natural predators – You can purchase beneficial nematodes to release in your garden. Nematodes are the natural predators of many insects. They work by invading the bodies of their prey and consuming them from the inside out. There are specific nematodes that work on different insects. They will not harm humans or pets.

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Michelle Weaver

Michelle Weaver is a former pastry chef of thirty years who reinvented herself during the pandemic, now happily earning a living through freelance writing and selling her art. She and her significant other live in an 1895 farmhouse in North Carolina, where they have several acres, allowing her to garden to her heart’s content. When she’s not playing in the dirt, she enjoys hiking in the nearby mountains, creating new vegetarian recipes, and photographing the wildlife that comes to visit.