This is an underground greenhouse posted on treehugger.com. Actually called walipini (an Aymara Indian word for a “place of warmth”), this design uses thermal heating to help keep plants warm and growing even in very cold climates.
Best of all, according to the Benson Institute, their 20-foot by 74-foot walipni field model out in La Paz cost around $250 to $300 only, thanks to the use of free labour provided by owners and neighbours, and the use of cheaper materials like plastic ultraviolet (UV) protective sheeting and PVC piping.
For more information on the walipini do a Google search for ‘benson institute walipini’, there are several good links for it, or check out this PDF by the Benson Institute on how to build one.
