Penelope Periwinkle wrote in message . ..
On 2 Oct 2004 05:18:01 -0700, (Dave) wrote:

I'm pondering what I might do to more efficiently heat my small
greenhouse to a minimal extent (40F). With the increase in the price
of natural gas I wonder if electric would be about the same? I also
want to consider assembling a table with a clear plastic cover to
contain the heat to a smaller area. Perhaps I could create a heated
table top? That would be useful next Spring. I suppose resistance wire
in a thin bed of sand?

There was a thread on...rec.gardens, I think...a while back on
using a waterbed heater to warm a seed tray. There were several
people who had tried it, I believe, but also a couple of warnings
about fire hazards.

You could probably google under the rec.gardens hierarchy for
"waterbed heaters" and pull up the information.


I think a waterbed heater might be a little scary. That resistance
wire they use to prevent pipes from freezing might be safer. The idea
of a circulating water scheme is attractive and you could use it with
various sources of heat -- even solar -- but on the negative side it
itself could become another freeze risk unless you used antifreeze in
the water.

Dave