How to Kill Ants in a Vegetable Garden

You're growing a beautiful vegetable garden when you notice a hoard of crawling ants among your beloved plants. Before you panic and set about killing them by any means necessary, consider why they're there and whether they're really doing any harm. Of course, if they're damaging your plants, you'll want to eradicate them safely.

Many types of ants are actually beneficial to your garden. The tiny insects can act as sentries, helping rid your garden of other insects that may eat your seeds and plants.

Ants also till the soil in your garden, which is helpful in several ways, including:

Dispersing seeds.

Aerating the soil.

Distributing important nutrients to your plants.

Some species of ants, such as fire ants, sting and can damage your plants by tunneling into fruits and root vegetables, however.

Spreading cornmeal over your garden can help kill ants, but it may take several applications. Another safe solution for your plants is to mix equal parts of white vinegar and water in a spray bottle and spray it if you see the pests on soil or hardscapes. Dumping hot water on any mounds you find will also kill ants quickly.

Keep in mind that killing the ants you see won't always eliminate the problem entirely. To do that, you'll need to focus on eliminating the queen and the colony.

Ant baits work by encouraging the ants to eat a poisonous substance and take it into the colony, including the queen. Fire ant baits that contain spinosad and pyriproxyfen are safe for vegetable gardens.

Many spinosad baits are approved for organic gardening.  

They act quickly, killing ants by harming the insects' nervous systems. 

Reduce new eggs but do not kill existing ants. 

Can take several months to work because the existing ants have to die off naturally before the pest problem is resolved.

For best results, sprinkle bait around the mounds and over several feet of the lawn outside your garden as soon as you see the ants. Choose a time in the early morning or late afternoon when the ground is dry and rain isn't predicted -- water dissolves the bait granules.

Mix equal parts borax and something sweet, such as jelly or sugar water, and place it in a bowl near your garden.

Ants will eat the lethal mixture and take it back to the colony.

Borax can be harmful to pets and other animals, so use caution when using this method to avoid any accidental ingestion.

Certain ants may be attracted more to fats than sugars.

Chemical insecticides should be a last resort, but there are some approved for home vegetable gardens -- just be sure to check the label.

Spinosad, used in baits, is also commonly used in liquid mound drenches. These products are effective if you have several large anthills in your garden, and they work quickly. These products must be mixed with water. Check the product label for specific measurements. Most require around 2 ounces or 4 tablespoons of pesticide solution per gallon. Start by applying about 1/4 of the volume in a circle about 12 inches from the mound, then pour the rest on the mound itself.

Use designated measuring tools and a designated watering can or bucket to apply mound drenches.

Products containing carbaryl that state they are safe for vegetable gardens are effective for fire ant control. To apply these insecticides, mix 3/4 ounce of the product with a gallon of water and apply it over mounds and any other areas where ants are congregating.

Do not use products containing acephate in vegetable gardens, even if they are labeled as safe for lawns. Vegetables and other plants will absorb this insecticide through the roots.