This weekend soaphouse asked me if I knew of any organic solutions to ants in veggies, which is a GREAT question! I love questions that get me to thinking and push me to learn more.
Since I have an edible yard, where my kids have been encouraged to freely graze at will and pets are unable to understand warnings about not eating things, I am very careful about using any kind of poisons. This means I stay away from not only toxic synthetic fertilizers, pesticides, and herbicides, but even various “organic” pest or weed controls, since some would also be toxic to my family. In most cases, this means plants are often left to fend for themselves beyond any kind of manual labor on my part.
So to be totally honest, I really haven’t paid that much attention to ants in my veggies, berries, or fruit, unless I start seeing damage. Last year I saw some actual aphid farms on my artichokes and fava beans, which was being tended by ants. It was amazing to watch the ants moving among the patches of aphids, as if they were caring for livestock. But I quickly got past my fascination since my poor artichokes and fava beans were suffering. I solved the problem with some non-toxic and organic soap spray, which wiped out the aphid farms via suffocation due to the soap layer temporarily stopping air exchange.
Soaphouse’s question prompted me to do some more study on ants, which led to finding some interesting ways that other people have gone about dealing with them. The way to deal with them depends on how much information you have. I am going to focus on organic solutions, since that is what soaphouse asked for. A combination of methods would probably be the most effective way to go.
Attack their home If you can figure out where the ant nest is, you can attack it directly. One idea is to poor boiling water on it.
Starve them If possible; remove what they are feeding on, usually sweet things. Since in the garden this can be veggies, fruit, or berries, this might be difficult. I was able to do this in my garden by killing the aphid farms they were living off of.
Destroy their means of communication Ants communicate with scent trails. If you spray or powder strong smelling things on those scent trails, like vinegar, cayenne pepper, black pepper, baby powder, mint, it will disrupt them and the ants will be lost as to where to go. You could even try spraying/powdering your plants with these things to see if it will stop the ants from finding them.
Fill them full of holes Some have reported that dusting food-grade diatomaceous earth along the ant’s pathways will cut through their exoskeleton and they will dehydrate and die.
I find it kind of funny to see the parallels of fighting ants to medieval warfare, though this happens to be with ants rather than knights fighting castles.
When it comes to ants in my home and walls, I am not against using poisons. It seems like almost every year I have lived in my home, about this time of year I get an encroachment of carpenter ants.
These are nasty big black ants. They can bite really hard, as my Mom can attest to from the time when I was a kid and one went down the front of her shirt. As a seven year old kid, it was a kind of scary experience seeing my Mom running around the living room screaming and tearing at her shirt while some ant was biting her. I have no truce with these ants.
With carpenter ants I have no qualm about using poisons. I prefer using borax based bait, which they carry back to their nest and queen, and within a few days kills the nest. There are bait stations that are designed to keep kids and pets out of them. I look for the borax based bait stations, since many others kill the ants so quickly that they don’t get the stuff back to their queen, allowing her to bear more eggs to replace to ants killed, which I don't want.