I am certainly using heat but I also want something cosy for him in the night. I'm sorry about the blankets but I remember seeing them somewhere I'm not sure where.Hi Bella:
I doubt very much that you saw anyplace where Tom uses blankets. The only way blankets work is on a warm blooded animal, which a tortoise is not. You have to provide heat for a tortoise regardless what substrate you use.
I am guessing you are thinking of 'pig blankets' - a livestock heating pad, not a blanket. I don't know of anyone using them with small species like yours though.