Wallipini

[Michael Osman]

Hi, I'm in the process of building my first aquaponics systems. I don't have any questions about that (yet)...But I'm wondering if any one has heard of an underground greenhouse, also called a wallipini? It's suppose to be very efficient for cold climates like we have here in Idaho. It's dug deep, like 8 feet. The recommended size is 8' x 12'. The idea is that if you're below the frost line, the temperature wont fall below 50-60 degrees F.....I saw this idea in the news paper (yes, there is still such a thing :D  )              Sorry the pics so blurry...

[Jim Enterline]

Michael,

I have a friend here in Missouri that is in the process of building one. After trying to heat a regular greenhouse last winter he dug a wallipini this summer and is in the process of moving his tanks and grow beds into it. His is some different than your picture in that he left a ledge on the north side and has a row of barrels of water for heat absorption and catching water off of the roof for top off water. The south roof is polycarbonate panels and it sets about 1' out of the ground to allow for the dirt to be backfilled up to the roof to divert runoff away from he wallipni. Sorry no pictures and no statistics yet as it is just being started. But looks to me like it is very feasible.

[Michael Osman]

That sounds great! I'm not going to be able to start digging till next spring... I'd love some updates on how well it works, if that's okay?

[Ian Cameron]

Michael, I live north of you in central BC. I built a walapini style this summer. The pics are posted in the cold weather group. So far, its working well. Temps down to 37F the last few nights. There is a largish wood heater that I bank with birch at 8pm and let it die naturally. So far, 6am temps have been between 62 and 68F. Just waiting for that -30 weather to kick in in January to see how it will all go.

[Michael Osman]

Cool, I'll have to find the cold weather group & take a look.

[Converse]

I Have a basic wallipini question for all of you....hopefully it will not be one of those "stupid" questions...

   So you build this wallipini into the ground because you live in colder regions...What about snow build-up?  I live in the Cascade Mtns. and have the perfect spot for a wallipini, but what to do with all the snow that builds up around the wallipini is  a concern I have.. Can anyone answer this?   Currently we have above ground greenhouses that are a bear to keep warm. The snow slides off and piles up around the gh....After a fashion we have to dig it out, depending on how deep the snow gets..On a wallipini I can imagine the snow on the ground around the wallipini would build up higher that the roof line. Once you get rain and ice on the built up snow round the outer edge of the wallipini ( ice gets built up on top of  the snow out here so you can walk on top of the snow some times) where does the roof melt-off water go? I am correct that the snow and ice will not build up on the roof due to the natural heating that takes place - along with the water thermal mass?)..So would a wallipini be practical in a cold region that gets snow and ice build up?  I am very intrigued by this possibility out at my place,

- Converse

[Michael Osman]

I wonder if you could let it melt down into the walipini & collect it for later use.

[Michael Osman]

Jim Enyerline's friend collects the water off the roof...should work for snow too.

[Michael Osman]

Oops..Enterline...sorry Jim...

[Ian Cameron]

So far this year we've had a couple of feet of snow, and it does not build up very much except around the edges where the heat is considerably less than the center. I have a double layer of poly that is inflated from inside the GH. Looks like one of those skylights, only much bigger, as it is naturally domed. The plastic at the edges was run into gravel filled trenches to take care of run off. If I my finances were better, I would have installed polycarbonate panels on steel tube runs and put in a gutter sytem back into the GH. As it is, I have a LOT of condensation between the poly layers, which is a shame, as I have no viable way of collecting it without compromising the "bubble" of air which does the insulating for me. So far however, I am very pleased with how little additional hear is required to keep temperatures between 23 and 28C, with outside temps ranging from -5 - -30C. Those  earth back and side walls seem to be doing the job I had anticipated. BTW, be prepared for bugs to set up shop! This environment makes them think its high summer (up here at least).

Converse said:

I Have a basic wallipini question for all of you....hopefully it will not be one of those "stupid" questions...

   So you build this wallipini into the ground because you live in colder regions...What about snow build-up?  I live in the Cascade Mtns. and have the perfect spot for a wallipini, but what to do with all the snow that builds up around the wallipini is  a concern I have.. Can anyone answer this?   Currently we have above ground greenhouses that are a bear to keep warm. The snow slides off and piles up around the gh....After a fashion we have to dig it out, depending on how deep the snow gets..On a wallipini I can imagine the snow on the ground around the wallipini would build up higher that the roof line. Once you get rain and ice on the built up snow round the outer edge of the wallipini ( ice gets built up on top of  the snow out here so you can walk on top of the snow some times) where does the roof melt-off water go? I am correct that the snow and ice will not build up on the roof due to the natural heating that takes place - along with the water thermal mass?)..So would a wallipini be practical in a cold region that gets snow and ice build up?  I am very intrigued by this possibility out at my place,

- Converse

[Deborah M Espie]

I am planning on constructing one this summer. I am in northern NM at about 8400 feet. We have a very short growing season and alot of wind.

If you haven't seen it, this seems to provide very detailed information for construction. www.bensoninstitute.org/Publication/Manuals/Walipini.pdf
If you get alot of snow, I think the roof/covering will have to be re-considered, maybe. My background is with old wooden bar greenhouse construction.

[Ian Cameron]

Yeah, I can imagine very late and very early frosts at that altitude. I built mine using  the Benson Institute guidelines, with 4" sewer pipe for rafters and supported in the centers. This summer I plan on increasing the angle of the roof slope from 12/4 to 14/4. For sure, double layer your roof covering or you will wind up losing a lot of valuable heat. The walapini is a great flywheel for the absorption and releasing of heat. If you get lots of sunshine, as I suspect you do, make sure to have a good venting system. One day before last Christmas it was down to -22f, sun was shining and it was 88f in the structure, with a very small fire to keep the FT warm. I think you will enjoy the experience of building and growing in yours.

Deborah M Espie said:

I am planning on constructing one this summer. I am in northern NM at about 8400 feet. We have a very short growing season and alot of wind.

If you haven't seen it, this seems to provide very detailed information for construction. www.bensoninstitute.org/Publication/Manuals/Walipini.pdf
If you get alot of snow, I think the roof/covering will have to be re-considered, maybe. My background is with old wooden bar greenhouse construction.

[Michael Osman]

The link takes me to what looks like a very good LDS sight, I'm having trouble finding the walipini manual though. Can you help me find it?

Deborah M Espie said:

I am planning on constructing one this summer. I am in northern NM at about 8400 feet. We have a very short growing season and alot of wind.

If you haven't seen it, this seems to provide very detailed information for construction. www.bensoninstitute.org/Publication/Manuals/Walipini.pdf
If you get alot of snow, I think the roof/covering will have to be re-considered, maybe. My background is with old wooden bar greenhouse construction.