While weeding my garden I found a bunch of ant nests (red ants and small black ants). My first inclination was to destroy the nest and send them packing, but I didn't know if they might aerate the soil, or keep worse pests at bay. Are they of any benefit to the garden?
In my areas of knowledge (Seattle and London), the ants don't make a real difference one way or the other. They won't damage your plants, nor will they give them much help. Of course, I can only speak to the small black ants, but as far as I know even the larger, more aggressive ants are more of a threat to the gardener to the garden. My sister lives in North Carolina and has to deal with fire ants, but she has to attack them because of the danger they pose from biting humans, so they're dealt with long before they could do anything to her garden.
I generally would take a live and let live approach. As long as they're not overrunning your garden or biting you when you're gardening, they aren't going to be a serious issue, and there will likely be much more damaging bugs to focus your time an energy upon.
The ants will feed aphids! When you see aphids it would be too late to save your plants, especially herbs. My suggestion is to use ant bait to kill them. Just place the toxic bait in their daily path.
A few years ago, my home had ants appearing from time to time and they were so annoying. I used an ant bait, mixed with bread and sugar, to attract them. After a few months, they just disappeared.
Ants do spread aphids around. Small black ants was seen around/in my pots starting spring. By July potted plants, even geranium, was affected - ants brought aphids, mildew spots appeared, plants was stressed and not healthy. Ants was noticed during watering - they was running from under the pots, closer look revealed ants in almost every pot. Insect killers did not really help, aphids damage was already done (to annuals), small bushes in the pots showed yellow leaves, black spots and all other pleasures. To the end of summer almost all annuals was destroyed. Next spring all pot`s soil was replaced, ants seen around. Sprayed top/sides + around pots with ants killer (safe for pets), used ants protector (spray) every month around the house and pots. No aphids, no ants, no problems.
Whoa! You guys obviously haven't watched 'Ants'...that animated movie with Woody Allen, Sharon Stone, Stallone...grin!
I've never had problems with ants. This new garden I've got is riddled with ants, all types of ants. I know they domesticate aphids (isn't that cool?) but whenever I see aphids a spray of soap or neem takes care of them. It takes awhile for aphids to damage a plant. As soon as I see them I think huh! I'll wait until evening then I grab a pre-made sprayer with organic dishsoap or neem and spray. I don't like accidently spraying bees or beneficials. I've heard that both are safe for bees, but I haven't been convinced. And I don't have to worry about sun/water/chemical burns spraying in the sunlight either.
I've got all kinds of plants in my greenhouses, all kinds of ants and no aphids, so far. I'm glad we don't have fire ants! I like rsgoheen's live and let live attitude. Those ants are so amazing, they work so hard, never think about themselves and I admire them...like bees and other hive insects.
When you put ant bait down, the ants carry it back to the hive and it kills the entire hive. I need to look it up to see if it would kill the sparrow that ate the ant. I again side with rsgoheen...there are worse problems in the garden than ants. Maybe my opinion will change as my gardens are going to be seriously ant-challenged here in central Oregon. But so far...no problems.
Use of pesticides is like putting a bandaid on a preventable problem. They should be used only as a last-resort. Gardening is a process where humans are the weak link. Nature is teaching us how silly we are to think we can control everything when we know so little. We gotta relax to be good gardeners.
I have ants in my allotment. They've lived in the compost heap a couple of times and did a brilliant job of turning it into lovely compost. In my organic system I use the compost heap area to grow vegetables the following year, and start a new heap (covered with carpet) in another spot. When I take off the carpet in spring and start digging it over they move on.Today I discovered them in a plastic compost bin I also have, which is a new departure. I agree with people who say we should learn to live with them. They're fascinating little creatures and part of the eco-system for a reason. We've messed up our beautiful planet enough. When my little robin comes looking for bugs I'm so happy there are no toxic chemicals in my plot to harm him.