Farmers have been trying to extend the growing season of their crops for hundreds of years. So far, the greenhouse has been the dominant technology, since it doesn’t usually require electricity to operate. The problem with setting up an off-the grid greenhouse is that the typical, “glazed glass” structure can be prohibitively expensive to construct. That’s where a the in-ground greenhouse comes into play.
A much more affordable and effective alternative to glass greenhouses is the walipini (an Aymara native word for a “place of warmth”). Essentially an in-ground “pit” greenhouse, this earth-sheltered greenhouse taps into the thermal mass of the earth, so that much less energy is needed to heat its interior than a similarly-sized glass greenhouse. Obviously, you need to take drainage and ventilation into consideration while building a walipini, but the Benson Institute at BYU has a few pointers on how to handle that, as well:
The Walipini utilizes nature’s resources to provide a warm, stable, well-lit environment for year-round vegetable production. Locating the growing area 6’- 8’ underground and capturing and storing daytime solar radiation are the most important principles in building a successful Walipini.
The Walipini, in simplest terms, is a rectangular hole in the ground 6-8′ deep that’s 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 sun’s rays to penetrate creating a warm, stable environment for plant growth.
If your browser supports PDF viewing, you can check out the full Benson Institute manual to build your own in-ground greenhouse, below, or download the full walipini manual here.
Keep in mind, also, that an in-ground greenhouse like the walipini could also serve as warm out-door storage for your animal hutches and small-scale hydroponic systems, making it a perfect “go-to” solution for a number of off-grid logistical issues … but the best part is the price: BYU pegs the materials cost at just $300 USD!