Keeping potting medium warm?

[Shyulace]

Oh thanks for the link!
I coincidently do have a propagation mat but I wasn't sure if that would provide sufficient heat to the container. I know the clay pots I have wouldn't hold/receive much heat compared to plastic containers. However what about if its a container with slits in the side as well? I figured the air movement would take out all the heat.

But its better than nothing Thx again