Ants are beneficial to your garden. They de-compact and aerate the soil, aid decomposition and also kill pests.
The ants themselves are not the issue, more so the anthills that they create. The ants can deposit appreciable amounts of soil on your lawn (a bit like mini molehills), which can then cause problems. They make the lawn uneven and can cause scalping when the grass is mown, resulting in the soil being smeared over the lawn. This problem is made even worse if the lawn is wet when mown.
How can we control ants in our lawn?
Short of dousing the nest with boiling water, there is not a great deal you can do about ants in your lawn. Unless their nests are causing particular problems, they are best left alone. Even if you can destroy a colony, it is likely that it will quickly be re-colonised and the whole process will commence again. There are some DIY products which might help control ants, such as ant powder. This can be applied by creating deep holes directly into the ants’ nest with a garden fork or spike. The holes can then be filled with the powder. For an organic approach, ‘Nemasys Nematodes’ can be applied between April and October. There have been some reports of good results with these when used against ants.
Do mechanical treatments help?
The only effective mechanical way of dealing with anthills on your lawn is to pick a nice dry day and scrape them off with a shovel, or brush them vigorously with a stiff broom to scatter the soil over the lawn.