How to use tools: getting rid of ants

Tim Rumball looks at home-made and commercial ways of dealing with these insects

SOMETIMES you spot little piles of soil revealing the entrance to a nest between the cracks in paving, or maybe a pin-prick bite will be your first warning that ants are active in the garden. Small numbers of ants are always around and aren’t generally a problem. Ants do some good by aerating soil, helping to break down organic material, and devouring other pest insects. However, if numbers build up their nests can undermine plants; they ‘farm’ aphids on plants causing considerable damage; and some species like the red ant, wood ants and flying ants can bite.

There are more than 30 ant species in the UK. They often make nests close to seating areas where food crumbs provide an easy meal, so the first line of defence is good hygiene. Clear up around outdoor eating areas; don’t leave pet food on the ground for long periods; make sure rubbish bins are covered; and keep compost bins enclosed and turn them regularly to disturb nests.

Organic deterrents

Depending on the species, ants eat pretty much anything, but they particularly like flower nectar and are attracted to both fatty protein-rich foods, and to anything that produces sweet, sugary sap such as fruit – and, interestingly, peony flowers that secrete a sticky sugar.

Ants communicate using pheromones, so they have a highly developed sense of smell. As strong smells are thought to disrupt pheromone communication, home-made ant deterrents include mint, lavender and other essential oils mixed with water and sprayed where ants are seen. Similarly, a mix of one part lemon juice to three parts water, or equal amounts of malt vinegar and water, are said to work. Or you can try finely ground cayenne or black pepper sprinkled along the ant runs.

Nematodes or home made

A shop-bought ant deterrent, Nemasys Natural No Ants ( nematodesdirect. co.uk) uses biological nematodes to scare off the whole ant colony without killing them and you just water it onto the nest. It’s a bit pricey at £13.99 plus delivery, but it’s a green option that’s well worth a try. Home-made ant killers include boiling water poured directly into the nest; soapy water sprayed onto the ants; powdered cinnamon, or foodgrade diatomaceous earth (available on the internet), or a mix of baking soda and sugar, sprinkled onto the run. Anecdotal evidence suggests that while all these home-made deterrents and killers have some immediate local effect, they don’t destroy the colony so ants are likely to remain a problem.

Shop-bought deterrents

Many shop-bought organic ant killer products such as Deadfast Ant Killer Plus Powder ( gardenhealth.com) are also dependent on direct contact. They, too, are unlikely to destroy a whole colony, but will be effective at significantly reducing numbers, and as environmentally friendly options, they’re a good choice.

Chemical ant killers are much more powerful. There several different sorts, each with benefits and drawbacks. Sprays and powders such as Zero In Ultra Power ( toolstation.com) and Wilko Ant and Crawling Insect Killer ( wilko.com) get rid of ants you can see when the product hits them, but won’t kill the whole nest. There may be issues with pets coming into contact with these products, and powders can be messy.

Granules like Home Defence Ant Stop Granules ( sainsburys.co.uk) are an effective bait insecticide, killing the whole nest. There is anecdotal evidence that some ants won’t take them because the granules are (relatively) large.

Gel baits like Rentokil Ant Killer Gel ( homebase.co.uk), squidged out of a tube onto the run, are similarly effective at killing the whole colony, but can be washed away in wet weather. And finally, bait stations like Nippon Ant Bait Station

( mytoolshed.co.uk) are neatly contained, so are pet safe, and kill the whole colony, but may initially attract lots of ants and take up to 10 days to work. Some ants like fatty protein-rich food, while others like sweet stuff. Because of this preference, when using poisoned baits the effectiveness of the attractant used in each one will depend on the type of ant you have in your garden. You may therefore have to try different makes to get your ants to take the bait.

Ants help to aerate the soil and speed up decomposition of organic material, but they can also be a nuisance to gardeners

Organic gardeners can use Deadfast, which contains an extract of chrysanthemums, or Nemasys nematodes that scare ants off

This is the entrance to a nest beneath paving slabs – the bit below ground where they live will be much bigger

A small blob of ant-killer gel laid on an ant run will be carried into the nest by the ants and kill the whole colony

Pouring boiling water directly into a nest will kill the ants it reaches while the water is still hot, but ant nests can be huge and hard to reach