This low-tech technology is a true gift from mother nature.For as little as $300 you can create an underground greenhouse that will provide enough food to live on year-round.A walipini, meaning “place of warmth” from the Amaraya Indian language, is an underground greenhouse with a transparent (usually plastic) covering that stays warm by passively soaking up the sun’s heat and absorbing the earth’s thermal energy.
Photo credit: schweibenalp.ch
Fruits and vegetables can be grown year-round, making it ideal for communities in colder locations that can’t usually grow their own fresh and local produce during certain parts of the year.
photo credit: seasonsunityproject
This type of farming method isn’t exactly new, Walipinis have been used in South and Central America for decades, including one that can grow bananas at 14,000 feet in the Andes.The Walipini, in simplest terms, is a rectangular hole in the ground 6 to 8 feet deep covered by plastic sheeting. The longest area of the rectangle faces the winter sun—to the north in the Southern Hemisphere and to the south in the Northern Hemisphere.
A thick wall of rammed earth at the back of the building and a much lower wall at the front provide the needed angle for the plastic sheet roof. This roof seals the hole, provides an insulating airspace between the two layers of plastic (a sheet on the top and another on the bottom of the roof/poles) and allows the suns rays to penetrate creating a warm, stable environment for plant growth.
Minneapolis-based Seasons Unity Project builds walipinis and says these structures can be constructed in places with surface temperatures as cold as -10 degrees Fahrenheit and as few as four feet below ground level.