I don't really consider ants a pest in the garden, but in the house they can be a problem. In this article we will be talking about the run of the mill, small, black ant. I have no experience with fire ants, but hear that they can be vicious and quite a nuisance. Contact a local exterminator or county extension office if you do indeed have a fire ant problem.
As I said, in the garden, ants can be very beneficial. They help to aerate the soil and in many cases, they help with pollination as they move from bloom to bloom on some plants. They also eat the eggs and larvae of fleas and other garden pests. Some species of ants are attracted to certain plants. The plant provides food and shelter to the ant and the ant will fend off any predators of that plant. So as with everything in nature, there is a balance, and all creatures, no matter how much of a nuisance to humans, can be useful and necessary in the balance of nature.
If you notice a large congregation of ants on one particular plant, you can be sure that you may also have an aphid problem. In a way, the ants are beneficial, alerting you to the fact that you have aphids. If this is the case, please refer to my aphid article for ways to get rid of aphids, and in all likelihood the ants will disappear once the aphids are gone.
Ants can also be attracted to scale. I have not written an article about scale yet, but when I do, I will update you with that information.
If you find an ant mound in the garden, and the ants are truly causing a problem for you or your plants, I would suggest starting with the simplest and least offensive method to get rid of them; boiling water. Pour a pot of boiling water down the ant mound wait a few minutes and repeat. This may also kill any plants that might be right up against the mound, so be careful if plants are nearby. If you find that the ants scatter too quickly, you can cover the mound with a container and pour the boiling water around the container. Ants will climb into the container and you can kill them by pouring more boiling water into the container.
If you live in a dry climate with sandy soils, you may notice more ants in your landscape. You can help get rid of ants by sprinkling diatomaceous earth in and around the mound. Break the top of the ant hill up so the ants are more exposed and sprinkle liberally on the mound. This will only work if it will be dry for several days. Make sure it is horticulture grade and not the kind used in swimming pools.
I've found that soils rich in organic matter are less likely to have a huge population of ants. I don't know if there is any scientific proof to this, but I have noticed that parts of my landscape that are sandy tend to have a lot more ants than areas that are full of clay or good compost (organic matter). You may not be able to improve the soil in your entire landscape, but you can help control the ants in your garden by applying lots of compost every year and turning the soil once in a while. The added bonus; your plants will do better in the long run.
Now that we have tackled ants in the landscape, let's talk about getting them out of your home. This is always a problem for us in the spring time. If you follow these few simple steps, you can get rid of them pretty easily.