Walipini or Geodesic Biodome Greenhouse?
Normally I focus on geodesic greenhouses but this old-yet-new design caught my eye recently. Its got a weird name but it works and its cheap to build too. Its know as the Walipini and it utilizes natural forces to provide warmth, light and protection for year-round vegetable growing. Location, location location. In real estate and when building a greenhouse, even one 6’- 8’ underground, location is essential. Then capturing and storing daytime solar radiation as heat and plant growth comes next.
A Walipini, is a rectangle shaped hole cut into the ground (hire a backhoe!) then covered by greenhouse plastic. The long face of the rectangle aims to the winter sun while a thick wall of rammed earth at the back of the building soaks up any available solar gain. Then a much lower wall at the front provides the needed angle for supporting the plastic roof of the greenhouse. This roof seals the greenhouse, provides an insulating airspace, and allows the sun to create a warm, stable environment for plant growth.
Because the Walipini is an earth sheltered building it uses the thermal mass of the and seasonal temperature lag of the earth to keep the indoor climate stable, thus much less energy is needed to heat up the earth sheltered greenhouse vs. an above ground one. Of course, one must take care with waterproofing, drainage and ventilation, as well as solar alignment, just as you would when building any kind of greenhouse.
Best of all, a 20ft x 60ft can be build for a total cost of around $300, if you use free or your own labor of course! Cheap but effective, the Walipini underground greenhouse is a great way for growers to produce food all year round.
But, if you have high water table, are on bedrock, just love domes and or don’t have soil suitable for earth sheltered building, go with the biodome greenhouse. But if you have less money and lots of friends who like to dig, then the Walipini might be a great option!