My North Dakota Cistern-Fed, Solar-Heated Greenhouse

Enlarge Image Image Gallery PHOTOS BY THE AUTHOR

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

There's more than one way to build a lean-to greenhaouse!

North Dakota has a lot to offer the prospective homesteader. Bismarck (where I live) has relatively little smog or pollution, a low-density population, and—in general—a more relaxed way of life than you'll find in most other parts of the country. The one thing we certainly don't have up here, however, is a long growing season. And that—in a nutshell—is why I decided several years ago to build a lean—to greenhouse.

When I set out to build the conservatory, I decided that I wanted the unit to utilize solar heat and natural rainwater to as great a degree as possible. The first requirement was easy to meet: All I had to do was build the hothouse onto the south-facing side of my home and angle the glass walls correctly to take the best advantage of incoming winter sunlight. The second requirement could be-and was- taken care of by a cistern.

Briefly then, here's how the whole thing went together.

THE SUBTERRANEAN CISTERN

Although my house has no basement, it does (because of the depth to which frost penetrates In these parts) rest atop a 5'deep foundation wall. Which meant that it was a simple matter for me to build an underground cistern by [1] digging a 5'-wide by 5'-deep by 30'-long trench along the south side of the house, [2] laying up cement block walls on the three outer sides of the excavated area, and [3] pouring a 3"-thick cement floor the length of the trench.

I laid the cistern's walls up out of 6" X 8" X 16' cement-not concreteblocks. (Cement blocks are less expensive than the "aggregate" kind. Also, they're a lot denser and therefore easier to waterproof.) The mortar I used to bind the blocks together with consisted of fine sand and cement in a three- or four-to-one ratio, mixed with enough water to form a "mud" that would stand up when put in a pile.

I've experimented with all kinds of goop, to waterproof the cistern's walls and-after a lot of effort—I can't say that I'm satisfied with any one method, since I can't keep water in mine above the four-foot level. If I were to start all over again, I think I would first plaster the entire inner surface of the cistern ... just as grandpa would've done in the old days. Then I could apply a coat or coats of epoxy, tar, emulsified asphalt, or whatever to further seal the tank.

Water is piped into my underground cistern via downspouts connected to the eaves troughs on the house. (It's amazing how fast a little rain or snow on the roof will fill up a cistern. So, be sure-if you decide to rig a similar setup-that you put a bypass in the downspouts or figure out an overflow pipe arrangement of some sort. Otherwise you'll have a wet greenhouse on your hands at times.) I remove water from the cistern by means of a small hand pump installed in the "roof" of the water tank ... a handy combination to have not only for when I need to water plants, but in case of a fire.

RSS | Comments | E-mail | Print