6 Ways to Fight Garden Pests Without Chemicals

Tiny, polka-dotted red wings flutter and a ladybug lands on a leaf—one of the cutest moments in nature. But these famously adorable beetles have another persona: carnivorous predators.

When that little thing breezes into the garden, it’s hunting its favorite meal: aphids, miniscule green bugs that suck the sap right out of plants and rank as one of the most prolific garden pests out there. Plus, aphids secrete a sticky liquid called honeydew that ants love to feed on—meaning where there’s one bug, you can usually find the other.

For organic farmer Adam Navidi, ants are the mortal enemy. Anyone who’s ever had an ant problem in the house knows how persistent they can be, and in the garden, they’re just as annoying.

That’s why ladybugs are a gardener’s best friend—they can eat up to 75 aphids a day. And therein lies one of the big problems with pesticides. They don’t just eradicate aphids, ants, mites, and other potentially pesky insects, they also kill the good guys—including those faithful ladybugs. Not to mention, chemicals can seep into the groundwater and eventually end up polluting waterways.

Luckily, there are a few natural alternatives to warding off garden pests that will kill off the pests without harming beneficial insects. Next time you’re facing an insect invasion, try one of these six methods instead of the usual chemicals.

The right plants

One way to keep the garden healthy is bringing in plants that attract beneficial insects like ladybugs and praying mantises. Dill, marigolds, and yarrow will all do the trick. You can even buy live ladybugs and set them loose in the yard.

Plain water

For the most natural way to get rid of harmful insects, look no further than the hose. Spray your plants all over with plain water, including the undersides of leaves; this should make room for the good bugs to move in.

Vinegar

Keep the ants from ever finding your fruits and vegetables by attacking them at home. If you can find their ant holes, spray white vinegar inside—which kills ants on contact.

Diatomaceous earth

Navidi also sprinkles diatomaceous earth, a type of sediment made from the fossilized remains of aquatic algae, around his vegetables, fruits, and herbs. As gruesome as it sounds, it dehydrates the ants—they aren’t going anywhere. He’s also had success with spreading sticky tree sap around the beds to literally stop bugs in their tracks.

Chili garlic oil

Navidi has one more trick for especially hardy ants: “If they make it through [that] obstacle course, then I blast them with chili garlic oil,” he says.

The intense aromas of chili and garlic are utterly unappealing to pests. Imagine being inside a football stadium where a highly concentrated scent of red pepper and garlic permeates every cubic foot—you’d probably want to get out ASAP. The flavors aren’t appetizing to rodents looking for a free meal, either.

Find some in the international aisle, or infuse olive oil with garlic and crushed red pepper by warming them together on the stovetop.

There is a potential problem with using chili, though: it can be irritating to mammals’ lungs and skin. So if you have dogs, cats, rabbits, or other animals in the yard that you want to keep safe, skip this one.

Garlic water

For a safer natural pesticide, try making a solution of garlic and water. It has the same strong smell that insects can’t abide, but won’t harm pets if they go poking around the tomatoes.

Ingredients

6 cloves garlic, chopped
1 cup water

Instructions

Blend garlic and water until smooth. Let sit for at least 1 hour or as long as overnight in the fridge. Strain through a coffee filter into a spray bottle and top with water to fill. Store spray in the refrigerator up to one week.

Spray plants, including undersides of leaves. If using on edible plants, wash them thoroughly before eating to remove any residual garlic flavor.

Some people like to add a teaspoon of liquid Castile soap to this solution, but soap may also kill beneficial insects. Avoid it if you want a pure repellent—and if you want to keep those hungry little ladybugs around.

Photo credit: Alicia Cho