Hey there,
I'll try to answer all your questions in this one post.
"When" to hibernate: Carpenter ants are pretty good at following a biological clock which will start them preparing for a hibernation about this time of year. You can also try nudging them to get ready for hibernation by keeping them at slightly low temps, like 68 or 65F. Just don't start them in hibernation before they're ready, that will harm them. Take a look at my post & photos here, where I give examples and a super brief description of what hibernation-ready ants look like:
http://www.formicult...ure-what-to-do/
"How" to hibernate:
First, there's a general guide to hibernation in the Handy Links post under Important Topics on the homepage:
http://www.formicult...of-handy-links/
I'll add to that guide with a summary of anecdotal experience on this forum: Ease your ants into hibernation, and also ease them out of it. Ants should be slowly cooled, preferably over several weeks, with something like a wine cooler with an adjustable thermostat (if you don't have the advantage of a garage or attic that can do the same thing). There's posts on Formiculture sharing stories of Queens dying because they were thrown straight into 8C temps, or were brought right out into room temperature, with no adjustment period. I kinda preach too much about gradually adjusting temps in and out of hibernation, but I feel that's an important step that gets skipped and it's unnatural to ants to experience such huge temperature swings.
That's all. Hope that helps!
