How to Kill Underground Ants

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Things You'll Need

  • Insecticidal ant soil drench

  • Watering can

  • Garden sprayer

  • Powdered insecticide containing acephate, deltamethrin or cyfluthrin

  • Rake

  • Diazinon granules

Ants often build unsightly mounds in the landscape.

Soil dwellers, ants live in large colonies dominated by a breeding queen. They construct a diverse tunnel system. The ants carry soil sediment to the surface while mining out the cavities and corridors of their home. The sediment can produce a large, unsightly mound in the middle of a pristine lawn. Some ants, such as red imported fire ants (Solenopsis invicta), pose a serious risk to pets and humans through their painful bites. Killing the entire underground community can successfully manage an ant mound problem.

Step 1

Mix an insecticide ant drench with water in a watering can or garden sprayer. Follow the directions on the insecticide's label to successfully mix the substance. Use 1 to 2 gallons per mound.

Step 2

Pour the insecticide drench slowly over the mound. Thoroughly drench the mound to successfully kill all ant inhabitants, even the ones deep within the tunnel system of the mound.

Step 3

Sprinkle dry, powdered ant insecticide over the mound. Follow the directions for applications. Use a product that contains acephate, deltamethrin or cyfluthrin to successfully kill fire ants.

Step 4

Rake the ant mound as flat as possible right before applying diazinon granules. Follow the directions on the diazinon label to determine the correct amount of granules to use. Sprinkle the granules across the ant mound and rake gently. Spray the ant mound with water lightly.


Liquid insecticide drenches kill the entire mound in approximately three hours. Powdered insecticides take two or three days to successfully kill the mound. Diazinon granules will kill the ants within an ant mound, but may take several applications to successfully eradicate the entire mound. Insecticides containing acephate produce a strong and unpleasant odor at the mound for several weeks.


Keep children and pets away from any ant mound treated with pesticides.


Kimberly Sharpe

Based in Oregon, Kimberly Sharpe has been a writer since 2006. She writes for numerous online publications. Her writing has a strong focus on home improvement, gardening, parenting, pets and travel. She has traveled extensively to such places as India and Sri Lanka to widen and enhance her writing and knowledge base.