How to heat a worm bed?

Image by tofutti break
our worms came today!
it took forever to shred all of the newspaper for the bedding.

Question by FunFungirl: How to heat a worm bed?
How can I heat a worm bed. We are having freezing cold temps and this is the first time I have ever had a worm bed this cold? I have sun lamps and heat bulbs in the building but it just not enough. Is there anything I can buy that I can stick in the beds to heat the bed up or what can I do? Thanks
The worm beds are like 8feet wide and 22feet long and about 4foot deep.
There not in a containter there in a build that goes down to the ground.

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