Fire ant control

I have a 4ft x 13ft raised bed that has quite a few fire ants in it. I don't see any mounds, though the soil is heavily mulched with leaves so maybe the mounds hidden? I'm wondering if I should let the fire ants be or try to remove them. I haven't planted my seeds/transplants into the garden yet but will very soon. I want all the beneficial insects, so I hesitate to use something like diatomaceous earth all over the bed. What should I do?

-Paranoid in Texas

Ants are one of the most common backyard pests. While spraying the yard with pesticides is one quick and easy way to get rid of ants in the yard, this may not be a good idea if pets or small children use the yard too. Keep the ants away this summer, safely and inexpensively. You have stuff at home that can do the trick.

Fire ants are a big issue here, the best solution I have ever found has been one gallon of boiling water, poured straight into the nest. Queens don't recover from being cooked.

Fire ants are known to be good rototillers, soil aerators and soil builders, unfortunately they are also known for having a pretty nasty bite too as well as helping themselves to the edibles in the garden. One solution may be to plant something that requires very little maintenance that is a minor edible or non-edible, such as any decorative plant, or tobacco(which when made into a fermented tea makes a really nitrogen rich fertilizer) thus decreasing the amount of time you would spend near the nest.

In my opinion and experience fire ants don't take over if the land has a healthy and diverse plant and animal population. We've always had a very few fire ant nests here and there on our place, but in a dozen years they have never taken over or visibly increased in number. They barely rise to the level of slight inconvenience. I find the chiggers infinitely more horrible.

Controls I use are as Fred describes, boiling water directly on the mound. Continued disturbance of a mound will make them move out of the area.

Don't know how bad it is on the soil, but I use orange oil mixed with water to drench the mounds. Also, a fellow over in Grand Prairie who makes homeopathic Bio-dynamic preps told me once that , I believe it was 501, sprayed on the property had helped his fire ant populations. The guy sell this stuff, but I can't recall his business name. They also claim that just getting the soil microbiology working will help.

Cornmeal bait. Works great on regular ants, could maybe work on fire ants. Don't want to throw the baby out with the bathwater by killing all the other beneficial nematodes/microorganisms in your soil by applications of fluids that kill but cannot be directed specifically at the ants.

@Jay - Cornmeal bait...?

Yes, cornmeal bait. I don't know about fire ants, but for 'common' ants, it works fine.

Sprinkle plain old cornmeal (you probably have a 'not so fresh' box in your pantry anyway) around their nest and along the routes the foragers take. When the workers find it, they will take it back to the nest to feed the colony. Since it isn't toxic, most will begin eating it. However, the digestive juices in the ant's gut will cause the cornmeal to e-x-p-a-n-d. It will swell up in their guts, and I guess the cause of death could be called 'acute constipation'.

@John - Interesting! Will have to try this on my fire ants and report back to you.

Living on the West Coast, I know little about fire ants and their eating habits. Please try it on them, and report back (good news, or bad news). If it works on them, there are many that would love to know. It is about as clean and organic as you can get. Even if the colony only eats half of what was brought in before their demise, the leftover surplus is now organic matter within the soil.

This just in:

"This is a new twist to killing fire ant colonies. For those not familiar
with Walter Reeves, he is from the University of Georgia agriculture
department, specializing in home gardening. His television show,
'Gardening in Georgia ', is on each Saturday.

I know fire ants are picky eaters and any type poison that is effective
takes seven feeding steps before the queen receives it. Plus, if the
bait is stored in close proximity to any petroleum or fertilizer
products they won't touch it. Contact poisons that are on the market
just cause the colony to move away. A well developed colony can be as
deep as 30 feet and spread out some 20 to 50 feet from the mound center.
This was documented by studies done in the early 60's when they were
first sited in South Alabama .

An environmentally friendly cure for fire ants has been announced by
Walter Reeves on his Georgia Gardener radio program. Testimonials that
it REALLY WORKS are coming in.

Simply pour two cups of CLUB SODA (carbonated water) directly in the
center of a fire ant mound. The carbon dioxide in the water is heavier
than air and displaces the oxygen which suffocates the queen and the
other ants. The whole colony will be dead within about two days.

Besides eliminating the ants, club soda leaves no poisonous residue,
does not contaminate the ground water, and does not indiscriminately
kill other insects. It is not harmful to your pets, soaks into the
ground.

Each mound must be treated individually and a one liter bottle of club
soda will kill 2 to 3 mounds. Spread the word."

Tyler Ludens wrote:This just in:

...Simply pour two cups of CLUB SODA (carbonated water) directly in the
center of a fire ant mound. The carbon dioxide in the water is heavier
than air and displaces the oxygen which suffocates the queen and the
other ants. The whole colony will be dead within about two days.

Besides eliminating the ants, club soda leaves no poisonous residue,
does not contaminate the ground water, and does not indiscriminately
kill other insects. It is not harmful to your pets, soaks into the
ground.

Each mound must be treated individually and a one liter bottle of club
soda will kill 2 to 3 mounds. Spread the word."

OMG, what an awesome, inexpensive, ecologically friendly, and effective technique for controlling fire ants! I put it to the test this week on two fire ant mounds that had sprung up in inconvenient spots in my garden. First of all, despite the directions above, I poured an entire 2L of club soda into each mound just to be sure. Why not?! The stuff isn't poisoning the soil, nor killing other soil organisms, and the 2L bottles are $0.85 at Walmart! I poured each as slowly and gently as I could into the top of each mound. If you poor slowly enough, it is easy to prevent run off along the surface of the soil; the soda percolates very nicely down into the colony. Then after a few minutes I dusted the surface of each mound - still crawling with hundreds of ants - with some diatomaceous earth, just for good measure. Not sure if that killed any of them swarming above ground, because of residual moisture, but again: it costs next to nothing.

Sure enough, checking back 36 hours later I found both mounds completely silent. Not a fire ant to be found. The beauty of this technique, of course, is that the ants asphyxiate from the bottom of the colony upwards. Presumably this increases the chance of killing the queen, resulting in the colony's collapse. Could be that this was the case in my two mounds, or it could be merely that the colony decided to move itself somewhere else in response to the disruption, as fire ants will do. Either way, I call the experiment a total success because those particular ants are no longer blocking me from working in those particular spots were I was desiring to work. I will now use club soda to attack every fire ant mound I come across on my property. Even if I only succeed in chasing the ants around my land, each time the colony gets weaker. Some will no doubt eventually collapse, others will no doubt eventually relocate far enough away that I don't care about them (into my zone 5, or off of my property altogether). In time, I win.

Thank you Tyler for this wonderfully useful nugget of info!

A note of caution regarding club soda:

Yes, the CO2 will displace the oxygen and kill the fire ants...
...BUT, most of your soil's microbes also need that oxygen to survive.

After the ants are gone, I would suggest turning your soil to reintroduce oxygen into your soil.
A broadfork or garden fork should do the trick, but it may take some time to get the microbe life reestablished.
Perhaps this would be an opportune time to mix in some fresh compost, as that would introduce fresh colonies to the soil.

@John - True, of course. And excellent advice about using some good compost as inoculant. But I would still not consider the club soda approach as a dangerous method. The affect on soil life will be both localized and temporary, since nothing permanent nor toxic is being added to the soil. The microbes will bounce back and recolonize, and quickly I should think. I'm still sticking with this as my preferred method for fire ant control.