Dan Hatfield Ii wrote:Hi Carol,
I'm in zone 10a in Oz. I'm currently building a brick 6" heater.
Excuse the mess. I'm in clean up stage at the moment.
Once it dries out and I can re-seal any cracking in the mortar,
it will be rendered in a lime plaster and I have a granite slab for the
bench, bell and feed ready to be applied.
I think this style would suit a green house well.
You could use the bench (or benches) above ground or below soil level.
Another method could be to use earthenware pipe under the soil.
If it hasn't been mentioned...metal pipe will rust out quickly and a cob bench
will likely detroiate quickly in a moist greenhouse environment so brick,concrete will suit the job better.
happy to help or even build.