The boyslife project is a bed, not a bin. World of difference. In-ground over-wintering is described in RWC link below. Some of the cultural advice given along with the BL bed directions is flawed.[worms do not eat 'small stones']

Re: winterizing above ground bin, I guess that would depend upon your winter temps and what you used this year that failed.

Here is a link that might be useful: scroll down to Winter worm composting

Interesting idea, but I'm afraid it sets up someone who follows that recipe for disappointment. If you start selling worms in 2 months, you are unlikely to have a large enough population to sustain itself, especially since the article really stints on the need to feed the worms. (Small rocks?!)

The concrete seems totally unnecessary if the worms are happy, and would prevent the worms from exiting a bad situation and return when conditions are better. It could also turn your worm bed into a swimming pool of drowned worms in a hard rain.

If it ever gets cold enough for me to worry about "winterizing" my worms we are ALL gonna be in trouble. i just worry about heat. The neighbor across the street came over earlier today and asked where the worm bin I was building was. He seemed surprised I kept worms. I told him "in the house". He paused a minute then said "Makes sense...guess they would cook out here." And it's still May...

I know there are bad info on feeding and selling but that is not the question
and I'm sorry I sead bin instead of bed

ttac, http://www.garden.org/zipzone/ I am zone 5b. I keep my worms in my celar all year round. Nodoubt my compost heap holds compost worms in the summer and maybe the frozen winter. That is where my worms came from.

Methods I would use to winterize a bin in my zone are:

Put the bin in a green house.
Put the bin in a hoop house, a type of temporary green house.
Put the bin in a hoop house, in a second hoop house.
Put the bin in a barn with larger animals for a bit of heat.
Put the bin in a barn with rabbits and chickens for a bit of heat.
Use stryofoam outside the bin to keep it warm.
Use BSFL Black Soilder Fly Larve to keep the bin warm.
Use christmas tree lights in a system below the bin.
I would prefer not to do that due to having to use electricity.
One could build their bin outside, right out side of a celar window and keep the window open a bit and sort of a lean to shelter. South side of the house would be best for this.

Hope I answered you question.

One mostly needs worms to eat extra garden waste. So summer is when we need them most. The compost heap grows a new batch for us every summer right when we need them most.

The Boys Life article was a start. I am so glad you did your own research on the topic and found us. Keep asking questions and we will keep answering. You get to decide if we are right or not. I can mostly answer from experience of what not to do, having throughly tested every way not to do it right.

Although you lost all but two worms I bet before the others died they left you many cocoons to hatch in the spring warmth. Have you looked through your entire bin? If you start to feed the area again, think cantalope rind, watermellon rind, corrigated cardboard, jack o lanterns, monster zuchinni, fallen to the ground tree fruit, they should come back.

Either way two is enough. Ask Adam. :-)