How Do You Keep Ants Out Of Your Garden Plants

Severus Snape in Harry Potter. Walter White in Breaking Bad. Tyrion Lannister in Game of Thrones.

What do all these characters have in common?

They're morally grey — it's hard to tell whether they're good guys or bad guys because their contradictory actions seem to suggest both.

Just like great stories, gardens have morally grey characters. And one of these is the ant.

So if you've ever wondered whether the presence of ants among your plants is positive or negative, the unsatisfying answer is "yes."

The ant is both friend and foe, dear gardener.

Keep reading to learn about the effects of this ambiguous arthropod, as well as how to control it, should you so choose.

In the garden, ants provide natural pest control and other benefits.

How Ants Can Help Your Garden

Here are a few reasons ants can be nice to have around.

Ants Control Pests Naturally

Like ladybeetles, green lacewings, and other beneficial bugs, ants often help control pests (they actually support some pests, too — more on that later) by eating their eggs and young or disturbing them during feeding.

Ants are such an effective biological control agent, in fact, that some growers introduce them on purpose as part of an Integrated Pest Management strategy.

And this isn't a new idea, either. Accounts of farmers using ants to control pests date back to 300 A.D.

Ants Improve Pollination Rates

As pollinator populations decrease, many gardeners struggle to achieve consistent, hearty harvests from fruiting crops. (Sound familiar? Try hand pollination.)

But ants can assist! By marching from flower to flower in search of food, ants often act as unintentional pollinators.

Ants Support a Healthy Ecosystem

In traditional gardening, ants aerate the soil — digging tunnels that carry water, oxygen, and nutrients to plant roots. And they also speed the decomposition of organic material, such as leaves and dead insects, thereby fertilizing plants.

Tower Garden doesn't use soil (and is more efficient as a result). But ants can still benefit the overall growing environment. Because in addition to feasting on pests, ants themselves serve as lunch for larger organisms, such as lizards, frogs, and birds — animals that also help prevent pest problems.

Ants often farm aphids, much like the way humans farm cows.

How Ants Can Hurt Your Garden

A few ants in your garden isn't usually cause for concern. But if you find a concentration of them, consider the following.

Ants Increase Pest Populations

What do ants like?

If you've ever spilled a soda or bag of candy on the sidewalk, you probably know the answer. Sugar.

And guess what aphids (as well as mealybugs, scale, whiteflies, and other sap-sucking pests) naturally produce?

Yep. Sugar, in the form of a sticky liquid secretion (yuck, right?) called "honeydew."

Here's the interesting part: Much like humans farm cows, ants farm aphids — protecting these bad bugs from predators so they can "milk" honeydew from them.

They'll then carry the honeydew back to the nest to share with the queen and other workers. And sometimes ants move aphids to their nest or better plants.

The scientific term for this relationship, if you're curious, is mutualistic symbiosis.

Ants Cause Pain and Property Damage

Some problems ants may cause concern your garden experience more than your garden itself. And there are two types of ant, in particular, that tend to be troublemakers.

Perhaps the most infamous ant species, fire ants will sting when provoked. And their venom produces a painful welt that lasts for several days.

Needless to say, if your plants are swarming with fire ants, harvesting could be an unpleasant experience.

Though they can't sting like fire ants, carpenter ants can bite (with powerful jaws) and then spray formic acid — which creates a burning sensation — into the wound. So… a carpenter ant bite isn't a fun experience.

But the biggest issue with this common ant species is its nesting habits. Carpenter ants build their homes in wood. And they aren't very picky about what type of wood — your home's structure is just as attractive as a decaying stump.

If ants become a problem, there are several ways to control them.

How to Control Ants in Your Garden

If you've decided ants don't belong in your garden, there's something you should know: Ants are among earth's oldest living creatures. They actually existed alongside the dinosaurs.

Which means they survived a mass extinction event.

Which means they're pretty good at adapting to survive.

Which means controlling them in your garden could be challenging.

Plus, there are more than 10,000 species of ant in the world. (And those are just the ones we know about!) So different ants might not respond to treatments the same way.

That said, here are six ways gardeners commonly control ants:

Get rid of aphids and other sap-sucking pests. This will prevent ants from hanging around to harvest honeydew.
Distribute artificial sweetener near the ants. Reportedly, this is fatal to ants (which might make you reconsider adding the stuff to your coffee).
Sprinkle ground cinnamon or cayenne pepper around your plants. This may help repel, but not injure, ants.
Place food-grade diatomaceous earth by trails and nests. Made from fossilized hard-shelled algae called diatoms, this fine powder dehydrates ants — as well as slugs and cockroaches. But it's completely safe for humans. (Note: It may take a few weeks to kill ants, and it must stay dry to be effective.)
Set a borax (or boric acid) and sugar poison trap. A quick internet search will return dozens of DIY recipes for borax- and boric acid-based pest poisons. But use these carefully — though borax and boric acid are natural compounds, they are toxic to humans and animals.
Pour boiling water on the anthill. This technique works only if you know where the ants' nest is, of course. And bear in mind, ants build their homes to withstand rain and flooding. So it may take several attempts before you kill the queen (and wipe out the colony).