Why Ants Come Indoors in Barnet
The black garden ant is what almost every Barnet call is about. A colony lives outdoors with a single queen, and worker ants forage outwards looking for sugars. When one finds something it lays a scent trail and the rest follow it, which is why the line into your kitchen appears overnight and always takes the same route.
Under the patio and the path
Paved areas hold heat and stay dry underneath, which is close to perfect for a nest. Barnet has a great deal of patio, block paving and decking laid directly against the back of the house, and fine soil pushed up between slabs is the clearest sign of a nest sitting a few inches beneath it.
Compost, raised beds and pot plants
The borough's large gardens mean compost heaps, raised beds and rows of pots, all of which are warm, loose and undisturbed. Moving a pot and finding pale eggs underneath is the usual discovery.
The way in
Ants need almost nothing: the gap under a back door, the seal around a patio door frame, an air brick, or the hole where a kitchen waste pipe passes through the wall. Wiping the trail off the worktop removes the scent line for an hour or two but does nothing about the colony outside.
Flying ants
For a few days in summer mature colonies release winged males and new queens, usually across the whole of London on roughly the same warm, still afternoon. It looks alarming and it is brief. It does mean, though, that there is an established nest nearby — flying ants come out of a colony that has been in the garden for some time.
What helps and what does not
- Wiping trails with detergent breaks the scent line, but only temporarily
- Sealing gaps under doors and around pipework is worth doing and lasts
- Keeping sugars, syrups and pet food in sealed containers removes the reward
- Boiling water poured on a patio nest kills the ants you can see and not the queen
- Shop sprays used on a trail tend to split a colony rather than end it
