In message , Mary Fisher
writes

I'd like to know too - but I'd also like to know what a heatmat is, please.

A heating element in a mat that can be laid down on staging etc. (like
soil warming cable is used in a propagator)

See this page for an example:

http://www.cmsgardens.co.uk/props.htm
--
Chris French and Helen Johnson, Leeds
urg Suppliers and References FAQ:
http://www.familyfrench.co.uk/garden/urgfaq/index.html