I don't know what you can do but I feel your pain. I had fire ants kill some of my plants by chewing (?) at the base of the plants. These were just annuals so in some cases I used ant killer but more offen than not I just let nature take it's course.
If no one here has an answer you could call the extension office at 744-5519.
Unfortunately there isn't always a good solution. Good luck.

yeah, I"m afraid they're going to eat the roots on my squash and corn.

Of course, if I found out that they ate the root knot nematodes and aphids, then I'd be conflicted on whether to commit ant genocide. I read somewhere that citrus oil mixed in water was good for controlling them, but I don't want to nuke my baby plants. Maybe I'll just pour a ring around the bed.

I am not expert at all on this topic but I did read another posting in this forum that mentioned that if you have 2 mounds you can use a shovel to get one mound and pour it over the second one. This to make them kill each other...

I have not tried it though...

Hope it helps...

From the UF link :

Individual Mound Treatments

There are many methods of treating individual mounds. The main advantage to this process is that there are so many choices available to homeowners though few may actually eliminate the colony. Individual mound treatments are most beneficial when there are native ants in the same area as imported fire ants. Reinfestation of any treated area, whether by broadcast treatment or individual mound treatment may occur. Six different methods of individual mound treatment are available :

Mound Drenches. Large volumes of liquid toxic to ants are poured over a mound. Liquids can range from using several gallons of hot water to insecticides mixed with several gallons of water. This method may not reach the queen, who may be deep in the nest, thus preventing colony elimination.

Surface Dusts. This method is very similar to mound drenches. A dust or granular insecticide is applied over the top of the mound and then watered into the soil.

Mound Injections. The use of insecticides that may be pressurized and injected into a mound. Often this method is more expensive, but more effective, than mound drenches. However, more time may be required for this method and leakage of the insecticide by the equipment may be hazardous to the handler. Again, the queen may not be affected and thus reinfestation may occur.

Baits. Baits can be used for both individual mound and broadcast applications. A small amount of the bait is sprinkled around the mound and the ants then forage and bring the bait back to the colony to feed on. This method is slower acting, but more effective then drenching, dusting, or fumigating a mound because the workers will feed the bait to the queen and brood, thus gaining effective control of the colony.

Home Remedies. Many homeowners will choose to pour boiling water or ignite flammable liquids over a mound. While these methods may bring about control, they are not recommended because they are both very dangerous, not only to humans, but also to the environment.

The link is interesting . There are other articles about fire ants on the same site .

Here is a link that might be useful: Red Imported Fire Ant

I've found AMDRO to be most effective in getting rid of fire ants. Just follow the instructions; put the bait AROUND the mound, not on top of it. And it doesn't take much at all. I've been using the same small bag for almost 2 years. DO check the mound(s) every day. If the bait is gone and there still seems to be some activity, put some more bait down, they will all die off soon.

Some where I read club soda was supposed to work. Takes the oxygen out of the soil they claim. I haven't tried it yet myself.

Remember, guys, this is in my raised bed vegetable garden. I think Amdro is right out. ;)

I hate fire ants! I remember my first experience with them when I moved here from Ohio. Have you tried flushing them out of the garden with the hose? That might be worth trying.

I believe that products containing spinosad kill fire ants and are considered "organic" and safe to use on produce. Check the label to make sure. Also spinosad is not safe for bees so only use if the plants are not flowering.

Noone here has mentioned cornmeal, which is non toxic, cheap as dirt, and worth a try. Just sprinkle it all around the area you see ants. When I did this in my garden, I noticed that the ants immediately started grabbing the cornmeal and carrying it around, presumably to take it to the nest and feed the queen.
I read somewhere that if an ant eats cornmeal, that it will more or less be the last meal the ant ever eats.
I did this in my garden, and the ant population decreased markedly. Sprinkle plenty of cornmeal on the dry soil, and within a few days you might see less ants. I like my veggie garden to stay organic, so chemicals were not an option for me.
I think this works on any kind of ant that will eat the cornmeal, as it has some protein and some sugar it should appeal to a broad spectrum of ants.
The other thing is, if the cornmeal does not work, keep the soil a lot moister, and the ants will move, at least away from your plants. I have read that if you see ants, then your soil is too dry. Just a comment for whatever it's worth. Perhaps mulching the area will help, too.

You say Amdro and other toxics are out, but if it's a matter of saving the bed or losing it, then it may be your best bet. Kill the ants, then move on to growing edibles in the bed again.

Try using an ant killer around the outside of the bed, remembering that they have alternate entrances up to 4 feet away. (i.e., spread it around!).

If that doesn't work, use it in the bed this season, then go back to your veggies next season. This is war! Do what you need to do to kill the enemy!

From what I've read and seen, combining ants from one mound to another doens't result in one mound being killed. Urban legend.
Ditto with corm meal, although I like the idea. Another urban legend.
Moist soil may be effective and I would definitely try that. But you'll have to keep it moist; they've already decided they like this bed so keeping them out will take effort.

Remember, this is war!!!

Kate (who really hates ants)

solstice - you are spot on with the advice .
The key is to kill the Queen .
Most home remedies or organic answers kill the scout ants
or worker ants but not the Queen .
Often two products are needed for long term effectiveness -
one as an immediate killer of ants you can see -
the other a product that is bait and taken into the nest to kill all
ants including the Queen .
Often you hear people talk about how ant nests just seem to
get up and move around the yard and not be killed .
That's because the whole group was not originally killed .
I think this will be a very bad year for fire ants .
I am heading out today to kill many colonies I found yesterday .
The ants are taking up residence under cow patties in my pastures .
Fire ants can kill a young calf, cat or dog .
tampasteve- keep us posted on your progress with the good fight !

Tampasteve,

I'm not sure why, but although we had lots of fireants when we bought this property, we have none on our acre now for a couple of years. I think it may be because we mulch heavily. It would be easy to try, organic, and good for your veggies. Consider trying mulching with leaves or grass clippings and see if they go away. In empty areas or rows you could put newspaper down first. I bet they will go away. If not, at least your plants will benefit from the mulch. They would benefit from the cornmeal idea too.

Coffee grounds!!!

A couple of years ago, I managed to get a nest of fire ants in my compost pile. I tried EVERYTHING...boiling water, corn meal, even read somewhere that molassess worked. NOT!! Of course I didn't want to use anything dangerous or unsafe, so I was stumped.

I read somewhere that coffee grounds worked, so I said, "What the heck?" and picked up a couple of free bags from my local Starbucks. Dumped it in, and in a week, they were gone!! It didn't kill them, they just moved elsewhere. I even did another test on some individual mounds in the yard and it worked too.

And your plants and soil will love it!

You can not flush out fire ants, they like water, in a flood or a river they will form a raft with their own bodies and float to shore, even fire ant killer products are a temporary fix, as they move on to another spot, and some of these products harm our plants, having lived here now 29 years, you must accept them as a way of life in FL. A huge fly has been released in Fl. that in time will help, it bites the head off of the ants. Some people have actually set the mounds on fire, it helps, but is rather drastic..So far Amdro is the best defense, even then they do come back. Good Luck!!

Thanks for all the advice, guys!

I've used Orthene with good results in the past, but NOT going to put it in my garden! Today I started watering in the grounds from the half-pot of coffee I make every morning. I'll do two of my one-foot square grids a day, to hopefully chase them out of the garden, while using Othene on the only visible mound, about 50ft away.

tampasteve
I was successful with diatomaceous earth in Phoenix when I had an invasion of fire ants.