Natural Building Blog

Earthbag Building & Other Natural Building Methods

Earthbag Pit Greenhouse Plans

Mike Oehler’s pit greenhouse design

Mike Oehler’s pit greenhouse design


I see at least two main approaches to building a pit house with earthbags:
1. Mimic Mike Oehler’s greenhouse design using earthbags instead of poles and shoring.
2. Mimic conventional walipini pit greenhouses. That’s what I’ve chosen to do in the following drawing. It’s very similar to typical walipini’s, so follow the directions in the link. Which one is best? It would be good to build both designs and measure their performance to see how they compare.
Earthbag pit greenhouse insulated with scoria or pumice (click to enlarge)

Earthbag pit greenhouse insulated with scoria or pumice (click to enlarge)


Related:
Earthbag Pit Greenhouses
Note: high quality greenhouse plastic film is recommended, not ordinary plastic sheeting.

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23 Responses to “Earthbag Pit Greenhouse Plans”

  1. Denzil says:

    I wonder if this would work in the humidity of the Philippines…

  2. Jim grieco says:

    Thanks Owen! The rough opening now is 40’x60′, taking into consideration room for the bags and stone backfill. I’m thinking around 30’x50′ finished. The walls will be between 6′-8′ high to ground level.

    Jim

  3. Jim Grieco says:

    Hello Owen,

    Getting ready to excavate for the Walipini.
    Quick questions:
    Do the corners of the walls need to be extended out for buttressing?
    Do you need a bond beam before connecting roof?

    Thanks
    Jim

    • Owen Geiger says:

      The walls are partially underground, right? If so then the earth or earth berm provides adequate buttressing.

      Bond beams are important for tying walls together and securing the roof. Depending on the size, budget, etc. you might get by using 2x6s spiked into the bags with rebar that’s bent over the last few inches.

  4. mary thomas says:

    This is awesome. Underground green house. I thought two ways to cool down in summer. Roll shade cloth over top. Hand cranking would work. In summer clean out fireplace, insert fan to blow warm air outside. FYI :)

  5. Cameron says:

    Thank you so much for your reply. To elaborate a little more on my design I just want to reiterate the fact that the bulk of this structure will be underground (not sure if this has any effect on the design). I had considered the use of rebar pinning and buttresses. My concern with the buttresses is with their orientation. Will they face inward (towards the inside of the structure) or outward to brace the wall against the push of the earth behind it? I haven’t been able to find very much information on underground building with earthbags so any information will be greatly appreciated. My hope is to build a small commercial greenhouse that is 100% energy self sufficient (primarily using solar for electricity). Thank you again.

    • Owen Geiger says:

      What you’re describing is certainly possible. You’ll have to find a local engineer, architect or designer who’s familiar with the soil and other important facts in your area. There are lots of ways of doing things…

  6. Cameron says:

    I was wondering if anybody had put any thought into the maximum size of a earthbag pit greenhouse. I’m a beginning farmer and have been putting a lot of time and research into starting a large scale pit greenhouse, something in the range of 30-40×80′. Is there any literature out there on the structural integrity of a greenhouse this large built from earthbags? If not what are your opinions.

    • Owen Geiger says:

      There’s no size limit if it’s designed and built correctly. You could build it as large as you want. But you have to understand how to work with earthbags. For instance, there’s often support (post, buttress, etc.) every 12 feet or so on long straight walls. You have to think about how the roof load with sit on the walls. Will the rafters push the wall in or out? You might want to include some rebar pinning and/or a concrete bond beam along the top of the wall to tie the bags together.

  7. Kelly Hart says:

    I wrote a review of Mike Oehler’s book that you can read at http://greenhomebuilding.com/articles/earth-shelteredgreenhouse.htm

    I think that it is an excellent concept, especially for cold northern climates; in fact I plan to make one for my little homestead, using earthbags. According to Mike having the cold sink is critical to the success of the plan.

    With the walipini plan that Owen shows, without substantially raised beds, much of the floor area would not receive enough sun in mid winter where I live.

  8. We are looking at using earthship design for our greenhouse project. Using old earth packed tires rather then earthbags would have more thermal mass storage. It will also have a cistern in the back berm for water catchment so the greenhouse will be self sufficient water wise, or as much as possible. We’re putting our plans together for the project next summer. In our winters, East Coast Canada, we need to put a thermal wrap behind our thermal mass wall and floor to help keep in the heat. Should be a fun project… Google earthship to check out these spectacular self sustaining homes.

  9. Thomas says:

    I remember something written about that cold channel. While I’m not entirely sure the science of it is as simple as he makes it out to be (cold air sinks, therefor we will have a pit for the cold air), having the raised beds does make a lot of sense for ease of access.

    Your design looks much larger, though, so raised beds would be harder to implement without a bit of dead space.

    • Owen Geiger says:

      Raised beds are a good idea, although they’re not shown. I am showing walkways between raised beds. The size is fairly common for walipini. In fact, I used the walipini drawing in the Benson Institute PDF as a guide.

      This is a fascinating project. You could grow all your food in a cold climate. I hope some people build these and report their results.

  10. Owen Geiger says:

    The walls of traditional walipini pit greenhouses are exposed soil. That may work in some areas, but it doesn’t seem very stable to me.

    Also note how soil excavated from the pit greenhouse could be used to build an earthbag house.

  11. I wonder if it would be better to only insulate the top 50cm below grade with scoria, since we are trying to use the earth to moderate the temperature. If we insulate it, we are taking away the thermal battery effect of the surrounding earth.

    • Owen Geiger says:

      I believe it’s better to store heat in the earthbags rather than trying to heat all the surrounding soil, especially in cold climates, which is where pit houses are built.

      Think of it like this: the cold/frozen earth would continuously suck heat away from the greenhouse. But with this design, you’re only heating the earthbags and the topsoil in the bottom.

  12. Dirt Bag Dad says:

    This is an awesome idea! I never thought about the $$ benifits of building an earth bag greenhouse. I was looking into transport containers. (The Big ones) My thought was that if I buried it then I could use it as a tornado shelter as well. (here in Texas)

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