Ant Control Guide

Signs you have an ant problem

The clearest sign is a visible trail — a fairly straight line of worker ants moving between a gap in the skirting or window frame and a food source in the kitchen. Ants follow a pheromone scent trail laid down by earlier workers, which is why the line rarely wanders. You might also notice small piles of fine soil near patio slabs or foundations outside, which often marks a nest entrance.

Garden ants vs pharaoh ants

Black garden ants are by far the most common indoor visitor — they nest outdoors, under paving or in soil near the foundation, and send workers inside purely to forage for food. Their trails tend to appear seasonally, picking up in warmer months as colonies become more active.

Pharaoh ants are a different matter: small, pale yellow-brown, and capable of nesting indoors year-round in warm voids like wall cavities or near boilers. They’re a genuine problem in flats and larger buildings because their colonies can split and “bud” into several smaller colonies when disturbed — which is exactly what happens if you spray a pharaoh ant trail with a contact insecticide.

Why ants come indoors

Worker ants are constantly foraging, and a kitchen offers a concentrated, reliable food source compared to whatever is available outdoors. Sugary spills, pet food left out, and unsealed food packaging are the most common draws. Gaps around windows, doors, cable entries, and patio doors are the typical entry points, especially where external pointing or sealant has worn away over time.

DIY control: bait beats spray

Contact sprays kill the ants you can see but do nothing to the nest, which is why a trail so often reappears within a day or two using a slightly different route. Gel bait works the opposite way: it’s a slow-acting insecticide mixed with an attractant, so a worker carries it back to the colony and shares it with the queen and larvae — the only approach that actually collapses the colony rather than just clearing a visible trail.

Place bait directly on or very close to the trail itself rather than somewhere general in the kitchen, since ants rarely detour more than a few centimetres to investigate something new. Avoid combining bait with a repellent spray in the same area in the first week or two, since repellents can put ants off the bait entirely.

Preventing ants long-term

Sealing obvious gaps with silicone caulk around windows, doors, and pipe entries removes the entry point rather than just masking it, and is the single most effective long-term step. Wiping up spills promptly and keeping sugary or greasy food in sealed containers removes the attractant that draws foragers in the first place. Outdoors, moving bird feeders and compost bins away from the house reduces the food supply that keeps a nearby colony active.

When to call a professional

Most garden ant trails clear up within one to two weeks of consistent gel bait use. It’s worth calling a licensed technician if the trail keeps returning from a different spot after two to three weeks of baiting, if you suspect pharaoh ants given the risks of DIY spraying already covered above, or if you’re seeing large numbers of flying ants indoors, which usually points to a mature, well-established colony rather than a small foraging trail. Professionals also use non-repellent insecticides not sold to the public, formulated specifically to avoid the colony-splitting problem.

FAQ