I'm considering building a walipini, but the small width of the land I can use raises some concerns.
Is a 4x3 m (13x10 feet) pit big enough to benefit from the warmth of the earth? I take the 2m (~6 feet) depth as some kind of standard.
The two main uses of the walipini would be:
1) the northern wall or the northern side (sunlit area) would serve as seedling growing area,
2) the southern side with a lower ground (darker area) would serve as a rain water reservoir.
Inviting your opinions here: would this be something reasonable or simply too small to work?
Location: Salt Lake Valley, Utah, hardiness zone 6b/7a
posted 4 years ago
The walipini is not a magic bullet and there has been some difficulty in adapting a greenhouse designed for tropical latitudes. Pit greenhouses (also search for: underground, semi-underground, earth-sheltered, sunken) are not a new concept and there are many options, including above-ground greenhouses that use earth tubes to moderate temperature.
You might want to track down a pdf copy of Mike Oehler's, The Earth Sheltered SolarGreenhouse Book. I would also recommend Solar Greenhouses: Underground, by Daniel Geery, 1982, Tab Books Inc. There are no digital copies available that I am aware of, but you can get a used copy at a reasonable price on Amazon (shipping to Hungary might be discouraging, but you would know better).
There is a lot on youtube, as well as a simple internet search using the terms listed above. My primary recommendation is to not get stuck on a name or a single design. Do as much research as you can and then do some designing to adapt to your particular site and needs. You probably won't get it perfect, but you will have something.
The Geery book goes into great detail about optimum glazed area and angles, as well as reflective materials.