"trg-s338" wrote in message
...
I'm building a 4 x 8 foot greenhouse planter and would like to embed
an electrical heating system, some kind of grid/mesh in the soil.
Just need to keep the soil around 70 degrees. Accomplishing this with
the least use of electricity is a plus if possible. Is this something
I can build or salvage off of an existing system? I would appreciate
any suggestions or direction where I can research further. Thanks.



something like this:

http://en.wikipedia.org/wiki/Trace_heating