Walipini: the self-produced underground greenhouse, with 200 euros you can grow a vegetable garden all year round

Build one greenhouse, here’s a chance to cultivate the vegetable garden all year roundeven during the coldest months. Communal greenhouses are usually made of glass or plastic and require energy and money to heat. An interesting alternative could be represented by Walipinione greenhouse built underground capable of exploiting the light and heat of sun even in winter.

The name comes from the Aymara languages, and the concept is similar to that of the pineapple stone, which was used, as the name suggests, to grow pineapples and other exotic fruits in Victorian Britain and on the cold plains of pre-Victorian Russia. -revolutionary.

During the Soviet era, similar techniques were developed for growing citrus fruits (oranges, lemons, mandarins, tangerines, grapefruits, limes, pomelos) in environments with temperatures below 30 degrees Celsius. In 1950, the Soviet Union had 30,000 hectares of citrus plantations, which produced 200,000 tons of fruit annually.

The underground greenhouse had already been designed 20 years ago to be able to grow even in the cold mountain regions of South America. This is a method that allows farmers to maintain a productive vegetable garden throughout the year, even during the winter months.

The construction of Walipini brought together knowledge regarding buildings at passive solar heating and the construction of underground homes. From the nonprofit institute for the promotion ofsustainable agriculture a real manual has arrived in America based in Benson that illustrates the functioning of Walipini.

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How Walipini works

Walipini exploits natural resources to keep the heat stable and allow the production of vegetables throughout the year. It is important that there is the possibility of capturing the light and heat emanating from the sun. It’s essentially about digging a moat of shape rectangular, which will be protected by a transparent sheet and which must face the direction of the sun during the winter. One is then made special roof which allows the sun’s rays to filter even in winter, heating the inside of the greenhouse and allowing the development of the plants.

When the temperature above the ground is cold, for example -12º C with wind chill, the ground temperature at 1.2 meters depth will be at least around 10º C in most places. By digging the Walipini into the ground, the large stable temperature driver called the “thermal constant” is exploited. Therefore, the additional heat needed from the sun’s rays, as they pass through the plastic and provide internal heat, is much less in the Walipini than in the elevated greenhouse.

Example: An underground temperature of 10º C requires heating the interior of the Walipini by only 16º C to achieve an ambient temperature of 27º C. An above ground temperature of -12º C requires heating a greenhouse by 38º C to achieve a temperature 27º C environment.

The danger posed by water

Water penetration into the walls and/or floor of the Walipini is destructive. If water seeps through the walls, they will collapse, if water rises from the floor, it will negatively affect plant growth and promote plant diseases. The Walipini must be dug in an area where its bottom is at least 1.5 meters above the water table. When all walls above ground are covered with a berm, a layer of impervious clay, such as bentonite, or plastic sheeting, should be buried approximately 15 cm to 30 cm below the surface of the berm. It must be sloped so that the water flows away from the Walipini towards the drainage ditches. In some cases, where the soil has a low permeability rate, clay or plastic may not be necessary. Be sure to dig a shallow drainage ditch around the perimeter of the Walipini that conducts wastewater away from the structure.

How much does it cost to build an underground greenhouse

The construction of Walipini, including the purchase of the necessary materials, according to the Benson Institute has a cost of about 250-300 dollars. It is therefore a rather economical solution compared to common greenhouses, which does not require the use of diesel for heating and which adapts to areas of the world with harsher climates.

What are the benefits of Walipini

This type of greenhouse uses the geothermal heat of the ground, creating a stable environment for plants. Soil temperatures at 1.2 meters depth generally remain between 10 and 15ºC, even in very cold climates. This allows you to grow vegetables and other plants that normally could not survive in such conditions.

Consult here the instruction manual for build Walipini.