An Underground Greenhouse or Walipini

An Underground Greenhouse in La Paz, Bolivia

I was chatting with my family online this evening and my sister mentioned an underground greenhouse. Intrigued, I followed the link she posted to an article at treehugger.

The Benson Institute developed the plans for the walipini or "place of warmth" as a way for families in La Paz, Bolivia, to garden throughout the year, despite the intensely cold mountain winters. The plans for the 20’ x 74’ greenhouse requires roughly $250-$300 in materials, assuming free labor and no need for heavy equipment. The Walipini manual indicates youll want about 100 square feet of growing area to feed a person year round.

The basic walipini plans could be further enhanced to include subterranean heating and cooling, since there is already significant sub-floor work involved to ensure adequate drainage. The plans also mention the benefit of incorporating water barrels to store heat energy. In my research associated with this article, I learned (or re-learned?) that water holds four times as much heat energy per unit volume as concrete. So using water to store heat energy is more effective than a trombe wall. And if the water you are storing is also irrigating your plants and providing a habitat for fish, all the better!

By the way, my book on Aquaponic Gardening will be available in less than a month. Very exciting! And I just saw the cover for the first time:



Pretty and green!

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If I Were Starting from Scratch

Southern States 250 Gallon Poly Stock Tank
Southern States has apparently created their own line of stock tanks, and it almost makes me wish I could start over from scratch. These bright blue tanks are UV protected and less expensive than Rubbermaid tanks of the same volume. Plus, there are a few unique sizes and shapes, like this 250 gallon tank that could be positioned in a corner.

Now that Ive lived the life of trying to observe my relatively dark fish in a black, covered stock tank, I also like the bright blue color. It wouldnt be everyones preference, but Im always thrilled to see a new, commercially available tank option!

In other news, I found out I have a supplier for expanded shale within a pleasant drive from DC. Matthew Ferrell has started a company called HydroShale, and is selling expanded shale that is the right size for aquaponics (3/4 inch). Its a bit pricey if you need to have it shipped, but if I can pick it up, I can get it in bulk for less than even the expanded clay beads Home Depot sells online (ViaStone from ViaGrow). Nothing will ever be as inexpensive as gravel, but I do like working with these lighter materials.

In the mean time, Im just glad I finally put up my greenhouse this past weekend. The garden and fish have done amazingly well without cover for the first portion of winter, but the temperatures will remain well below freezing for most of this week. But with the protection from the wind and solar heating during the day, I expect my garden and fish will weather this bitter week adequately well. Hooray for bluegill and goldfish!

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