Building geothermal tubes for worm composting (or vermicomposting)
As explained on the temperature control page, geothermal
heating and cooling is used with the outdoor wooden composting bin. This page details
the construction of the tubing needed to make this happen.
First, the end result. The black tubes are ABS and the grey
are PVC. The black tube sticking up will be the air intake, sticking up out
of the ground. The rest of the black tubes will be buried in the ground and
the grey tubes will be buried in compost.
1/4" holes were drilled in one side of the grey tubes.
These will be facing down in the compost bin. The other side has no holes and will
be facing up. This is so that fluid does not fall into these tubes.
Fly netting was then wrapped around the tubes so that the
worms don't start crawling into them.
1" diameter holes were drilled into a black tube and grey PVC
couplings were inserted into these holes and glued in place using
All the black tubes were assembled and the grey tubes were
then placed in the grey couplings.
The grey tubes were then removed from the couplings and
placed into the bottom of the composting bin with their ends stick out the
lower ventilation holes. (Yes, when I took this picture I did notice that
the newspaper on top was dry. :-))
The place where the grey tubes stick out was then covered
in silicone caulking to be waterproof.
The whole thing was then put together by inserting the
ends of the grey tubes into the grey couplings.
The whole thing in place, ready to be buried in dirt.