yes it's possible, although activity may be low at temps that low, depending on the bin - a large bin with no bottom will allow the worms to go deeper if they want as the temp drops, and over time the ground below will stay warmer than ambient air temps ... if you're using something like a rubbermaid tub, it'd need some insulation to last and work, although having it right up against the wall of the house could help

I have a bin about 3.5' X 8' free standing in the yard and the worms do fine thru the winter even when temps drop below freezing every night for weeks

Bill

Thank you Bill. Will it be enough to put some styrofoam around the bin? It is a small rubbermaid type and it will be against the wall of our house. Also, it is warmer during the day here... mid-sixties right now. We are in Santa Barbara.

I'd go for it, won't take much to keep the bedding temp pretty stable with those daytime temps

Bill

You can buy a cheap compost thermometer at the local garden store and leave it sticking in your worm bin/compost pile year round. Its good to check for hot spots as well as cool spots.

I have been wanting to start a bin for a while now but my other half won't let me do this in the basement where it is almost always between 60-75 degrees.

So I'm looking at starting this in the garage which is not temperature controlled but according to the gauges doesn't normally go below freezing even when it gets down in the teens at night.

My question is what size bin would I need to be able to keep worms in the garage all winter, and would I need to do anything special to help them out?

I live in Zone 7