I have been using worms for vermaculture indoors
with my can 0 worms system. This year I am planning
on expanding my worm bed to my 20X8' garden. I live
in Chicago and I'm worried about frost killing off
my entire population. I have at least 3inches of
compost/mulch mix on top of the soil. Does anyone
have other suggestions to help my redworms get through
the winter months???

My soil doesn't usually freeze here until January - sometimes earlier - how about getting a nice load of horse manure on right before it would normally freeze and then mulch that?

The one time I saw red wigglers being farmed in NH was in a large concrete tank under shelter of a barn.

Please bear in mind this was many years ago by a bait producer. I *think* the reason he gave for keeping then under shelter was a need for a higher minumum temperature in the winter.

I suppose if you had resonably well draining soil and a really-really big manure pile (for heat), them woims wouldn't care whether they was inside or not.