Joann, I'm sorry that this won't help you at all, but the second I saw your post I started singing

Ants in my whiskey barrel, shoo ants, shoo,
Ants in my whiskey barrel, shoo ants, shoo,
Ants in my whiskey barrel, shoo ants, shoo,
Skip to my Lou, my darling.

Hoping someone will have a more helpful answer,
ThinMan

Thin Man you will inspire me to make a shoo-fly pie with that song!!! You are too funny. Meanwhile I don't know whether to plant or not!
Joann

What if you soak it down and keep it really wet for a while....that got rid of the wasps in my compost!!

Nancy.

Ants can be a challenge! We have lots of them here - dry forest/perfect ant environment. They were in a compost pile once so I increased the moisture and they left. There was a large anthill near some coniferous trees but when I amended the soil, planted, and watered regularly they went elsewhere. They prefer a dry environment so keeping things damp causes them to move along.

We use a powder around our house to discourage them. I don't like to use really toxic things so don't try to eradicate them - which likely wouldn't be possible anyhow as there is so much 'ant' food around. They like to nest at the bases of coniferous trees. I just don't walk there - hate having them crawl on my feet!

This article has some suggestions altho I've found peppermint doesn't seem to discourage the ones I've had to deal with. I had them living at the bottom of the large pots I had my peppermint plants in one year! I even tried peppermint essential oil and they laughed. ;-D

Try keeping the barrels wet for awhile and see what happens.

Here is a link that might be useful: Getting rid of ants

You could pour a big pot of boiling water in there. Esp. if you are using a sterile potting mix, it wouldn't matter if it killed some microorganisms. You could always add some compost later when you replanted.

boiling water method sounds okay, unless you have great difficulty producing that much hot water.

I'd simply empty out the barrel (is this a half barrel or full?) and start anew.

Well this is a big full whisky barrel so emptying it out was kind of not possible. It would be too much work. I finally decided to just plant it and keep it well watered. I'll let you all know if the plants thrived or not. Thanks for all the suggestions!
Joann

In which case you could also try find the ants' paths and put in baits so the queen mother is killed off.

I had ants in a big plastic pot that had a hole in the bottom. The ants were living partly in the ground under the pot and partly in the pot. I dumped out the soil and moved the pot to a paving slab so there was no contact between the bottom hole and the ground. I refilled the pot, and so far, no more ants.

Lois in PA

Lois, That's a good idea.

I'm guessing this is too late, but if you haven't already, don't plant til you get rid of the ants. I had the same problem last year with my whiskey barrel planter. The ants did something to all the plants in that barrell. I have two barrels side by side. One had the ants and one didn't and the plants in the ant barrell all died. I tried to get rid of the ants and kept replanting with different things hoping they'd live, but until I got rid of the ants nothing survived. I tried a few things including ant traps, but I'm pretty sure it was the boiling water that finally worked. I'm emptying mine this year and starting fresh and I will definately put both barrels on something to prevent them from coming back.

Hope you have better luck than I did.

If you are just starting a new barrel, try not filling the barrel completely with soil. You could instead fill the bottom with rocks or old bricks -- anything that can fill up space. use a landscapers cloth to act as a dividing membrane and fill up the top parts with soil. You only need the top part to hold the plants anyway. In some cases, people just put in potted plants and changing them when they start dying off.

Daisy chain...I'll let you know how the plants make out. I sure hope mt ants aren't as bad as the ones that killed your plants!!!
Joann