How to get rid of ants outside: baits for the yard, patio and fire ant mounds

Step by step: how to get rid of ants outside

Safety first. Follow every pesticide label exactly: rate, timing and where it may be used. Keep children and pets away from baits and treated mounds, and store pesticides in their original containers out of reach. Fire ants sting repeatedly; wear boots and gloves near mounds and do not disturb them by hand.

1. 1

   Find out which ants you have and where they nest

   Follow trails from the patio, sidewalk cracks or plants back to the nest, ideally in the late afternoon when ants are most active. Look for soft, fluffy dirt mounds with no opening on top (often fire ants), small crater-shaped piles in pavement cracks, or trails up tree trunks. If ants sting in large numbers when a mound is disturbed, treat them as fire ants.

2. 2

   Clean up what feeds them

   Pick up fallen fruit, rinse sticky spills off the patio, empty pet food bowls after meals and keep trash cans lidded. Control aphids on shrubs, since many ants farm them for their sweet honeydew.

3. 3

   Place bait stations along trails and by nests

   Put outdoor bait stations or stakes right beside active trails and near nest openings, not on top of them. Use stations rather than loose bait where kids and pets play. Replace them as soon as they are empty.

4. 4

   For fire ants, broadcast bait over the yard

   On a dry day with no rain expected for 24 to 48 hours, spread fire ant bait over the whole lawn with a hand-held spreader at the label rate. Apply it in the late afternoon or evening when ants are foraging. Use fresh bait from a recently opened bag.

5. 5

   Treat problem mounds directly

   A few days later, treat mounds that are near paths, play areas or the foundation with a labeled mound product, such as a drench, granule or dust. Follow the label for whether to water it in. Leave far corners of the yard to the broadcast bait.

6. 6

   Wait, and resist the urge to spray

   Baits are slow: workers have to carry them back to the colony. You may see ants for 1 to several weeks while it works. Spraying on top of baits kills the workers that would deliver them.

7. 7

   Make the edge of the house less inviting

   Pull mulch, grass and plants at least a foot back from the foundation, trim branches touching the house, and caulk cracks where ants trail inside. Fix leaky hose bibs and drippy irrigation near the walls.

Why baits beat sprays outdoors

Baits reach the queen; sprays only kill the workers you see, and many of them run off into storm drains. UC IPM recommends placing baits near trails and nest openings outdoors, says prepackaged or refillable stations and stakes are the safest and easiest to use, and that it can take 5 to 10 days to see fewer ants. It also warns against spraying pyrethroids such as bifenthrin and cypermethrin outdoors, especially on driveways, sidewalks and foundations, because these products pollute waterways.

If ants ignore a bait, move it closer to the trail or try a different bait: some ants want sugar, others want protein or grease, and this can change with the season. NPIC suggests trying a lower-toxicity product first and reading the label before you buy.

The two-step method for fire ants

For yards with many fire ant mounds, broadcast a bait over the whole yard, then treat individual problem mounds. Texas A&M’s Two-Step Method describes it as the best proven approach for fully infested areas (five or more mounds per quarter acre).

• Broadcast bait between late August and mid-October if you can, when ants still forage and the weather is easier to predict. Baits work any time in the warm season.
• Apply when the ground and grass are dry and no rain is expected for 24 to 48 hours, and in late afternoon or evening.
• Test first: put a small pile of bait beside a mound and see if ants find it within 30 minutes.
• Do not use baits mixed with fertilizer or seed, and expect weeks to months for full control. Reapply once or twice a year.

Common outdoor ants and what to do

Ants that make it indoors are a separate job: see getting rid of sugar ants in the house or, for cleaning-only methods, getting rid of ants naturally. Call a licensed pest control company for carpenter ants in the structure, fire ants around a home with small children or allergies, or ants that return after two rounds of baiting.

Mistakes to avoid

• Spraying the trail right after setting baits, so the ants die before carrying bait home.
• Pouring boiling water or gasoline on mounds; it kills grass, can burn you, and the colony often just moves.
• Spreading fire ant bait on wet grass or right before rain, which ruins it.
• Using an old, opened bag of bait that has gone rancid; ants will not take it.
• Spraying insecticide on driveways and sidewalks, where it washes into storm drains.