Does Ant Killer Harm or Kill Plants in the Garden?

Ants can be both beneficial and problematic in the garden. While they help aerate soil and control pests, ants can also damage plants by feeding on roots and spreading disease. Some gardeners opt for chemical ant killers to eliminate ants, but this raises the question – will ant killer also harm or kill garden plants?

How Ant Killers Work

There are two main types of chemical ant killers:

• Contact insecticides – These pesticides kill ants on contact. They include sprays and granules formulated with ingredients like pyrethroids, neonicotinoids, and carbamates.

• Stomach poisons – These are bait products containing slow-acting toxins like borax. Foraging ants consume the bait and bring it back to the nest, resulting in colony-wide mortality.

Both forms are designed to be toxic to ants either through direct exposure or ingestion, But could they also pose risks to garden plants?

Risks to Plants

The risks depend on the specific active ingredients and formulation:

• Contact sprays – These are more likely to harm plants if leaves are directly sprayed, allowing chemicals to penetrate plant tissues. Systemic uptake can occur

• Granular products – Low risk of phytotoxicity since granules are confined to the soil surface with minimal plant tissue contact. However, some active ingredients may leach

• Liquid baits – Minimal risk when used properly in bait stations. Avoid contact with plant parts.

• Residual barrier sprays – Moderate risk depending on longevity and active ingredient. Could damage roots of plants in treated areas. Avoid planting in recently treated areas.

So while some ant killers present low hazards to plants, the risks increase if products contact foliage or roots. Careless application directly onto garden plants can definitely harm them.

Signs of Phytotoxicity

If an ant killer damages plants, these are some visible symptoms:

• Leaf scorching or yellowing

• Wilting, stunting, or abnormal growth

• Lesions, leaf loss, or dead spots

• Failure to thrive and reduced yields

• Plant death in severe cases of toxicity

Sensitivity varies based on plant species, growth stage, and conditions. Herbicide damage may not appear right away but can impact health over time.

Preventing Injury to Plants

Here are some tips to avoid unintended impacts from ant killers:

• Read product labels thoroughly and follow all precautions.

• Opt for baits or granular products that pose less risks to plants.

• Avoid spraying blooming plants and edibles ready for harvest.

• Prevent chemicals from contacting plant foliage, stems, or roots.

• Do not exceed dosage or frequency recommendations.

• Apply granulars directly in and around ant nests/trails, not beds.

• Use bait stations to limit bait contact with soil and roots.

• Consider integrated pest management (IPM) and exclusionary measures first.

• Water in treatments lightly to avoid runoff to plantings.

• Wait until plants are dormant or not present to treat garden areas.

Alternative Pest Management Options

For gardeners wishing to avoid synthetic chemicals altogether, organic and natural options can help control ants without harming plants:

• Diatomaceous earth – Dust this abrasive powder in nest areas and along trails.

• Horticultural oils – Suffocate and kill ants on contact while safe for plants.

• Insecticidal soaps – Potassium salts disrupt ant cell membranes but are low risk.

• Vinegar – Helpful as a repellent spray; can also kill ants with direct contact.

• Citrus oil – Repels and irritates ants with strong scent; derived from orange peels.

• Chili pepper – Contains capsaicin which is irritating; use as a repellent spray.

• Coffee grounds – Unpleasant texture and odor deters ants; also lowers soil pH.

• Crushed eggshells – Creates sharp barrier and alters soil pH to deter colonies.

• DEET – Effective repellent; avoid plant contact and environmental contamination.

The Impact of Ants on Plants

While ant killers carry some risks, severe ant infestations also negatively impact plants. Ants can:

• Damage roots as they tunnel through soil.

• Spread plant diseases like root rot between gardens.

• Farm pest insects like aphids that excrete sticky honeydew.

-Disturb beneficial mycorrhizal fungi around plant roots.

So allowing ants to go unchecked also threatens the health of garden plants and reduces yields. Finding the right balance through IPM allows you to control ants while protecting your plants.