In Finland ants survive the winter by going into a state of dormancy. Inside, it's so warm, that ants don't go to dormancy and they get little mixed. Ants might manage few winters without dormancy, but more experienced do not recommend it. Now it's late November and I though, that now it's time to put my ants to sleep for few months.
The hardest thing is of course to find a place, where is the suitable temperature. Or actually finding it is not that hard, because there usually is a fridge in every home, but the female living in our house has some stupid thoughts, that ants should not be kept there.
The temperature should be about 6c° to 8c°. The temperature outside can change from 5c° to - 35c° , so I can't keep them outside either.
My decision was to use the outer wall the thing we Finns call "tuulikaappi" (wind closet). It's the small room between outer door and hallway, where the temperature usually falls a little in winter anyway.
So I covered the other side of the formicarium with styrofoam to protect it from the warm and placed the other side against the outer wall. Now it seems, that I managed to drop the temperature to 10c°, which would do. At the moment, it's - 2,5c° outside, so the temperature is likely to fall more, but not below 0c°, which would kill the colony.