Can’t afford a glass greenhouse? Check out how to build your own underground greenhouse for cheaper and for growing veggies 365 days a year, even in cold climates.
Growers in colder climates often utilize various approaches to extend the growing season or to give their crops a boost, whether it’s coldframes, hoop houses or greenhouses.
Greenhouses are usually glazed structures but are typically expensive to construct and heat throughout the winter. A much more affordable and effective alternative to glass greenhouses is the walipini (an Aymara Indian word for a “place of warmth”), also known as an underground or pit greenhouse. First developed over 20 years ago for the cold mountainous regions of South America, this method allows growers to maintain a productive garden year-round, even in the coldest of climates.
Here’s a video tour of a walipini that shows what a basic version of this earth-sheltered solar greenhouse looks like inside:
- How a Walipini works and how to build one
- Designs for an Underground Greenhouse
- 17 Incredible Underground Greenhouses Around the World
- 1) Walipini From LaPaz, Bolivia
- 2) Pit Greenhouse Made With Local Stone
- 3) Underground Greenhouse In Mongolia
- 4) Pit Greenhouse With Good Insulation
- 5) Start Of A Homestead Walipini
- 6) Underground Greenhouse From Tennessee
- 7) Walipini From Sandstone In Texas
- 8) Patagonian Underground Greenhouse
- 9) Walipini From An Earthen Embankment
- 10) Pit Greenhouse From An Old Missile Silo
- 11) Walipini With A Drainage Ditch
- 12) Pit Greenhouse
- 13) Installing A Walipini Roof
- 14) Pit Greenhouse With Old Windows For A Roof
- 15) Hand-Dug Underground Greenhouse
- 16) Pit Greenhouse Made By Simple Ground
- 17) Walipini Built In Ladakh
- Many More Uses for Your Underground Greenhouse
- How to Build an Underground Greenhouse: Resources
- Best Books on How to Build an Underground Greenhouse
- More Underground Greenhouse Resources
- Underground Greenhouse Video
- An Underground Greenhouse? It’s Not Just A Fad
- Sign-up today!
- HOW TO: Build a Stunning Underground Earth-ship Greenhouse
- The Underground Earth-ship Greenhouse
- So What’s the Appeal in Building a Greenhouse
- How does an Underground Greenhouse Work?
- Pierre Fisette – Estrie, southern Quebec
- Maude Alary-Paquette – A low-budget greenhouse in Northern, cold Quebec
- Laurent Teasdale & Frédéric Bachand – growing a business in a cold climate
- The Walipini…Walawhat?
- Make Your Own Walipini
- $300 Walipini Design
- Walipini Videos
- Wait…It’s A Greenhouse…Underground?
- Other Benefits Of A Walipini Underground Greenhouse
- Planning Your Walipini Pit Greenhouse
- Walipini Infographic
- Final Thoughts
How a Walipini works and how to build one
It’s a pretty intriguing set-up that combines the principles of passive solar heating with an earth-sheltered building. But how to make one? From American sustainable agriculture non-profit Benson Institute comes this enlightening manual on how a walipini works, and how to build it:
The Walipini utilizes nature’s resources to provide a warm, stable, well-lit environment for year-round vegetable production. Locating the growing area 6’ to 8’ underground and capturing and storing daytime solar radiation are the most important principles in building a successful Walipini.
The Walipini, in simplest terms, is a rectangular hole in the ground 6 ‛ to 8’ deep covered by plastic sheeting. The longest area of the rectangle faces the winter sun — to the north in the Southern Hemisphere and to the south in the Northern Hemisphere. A thick wall of rammed earth at the back of the building and a much lower wall at the front provide the needed angle for the plastic sheet roof. This roof seals the hole, provides an insulating airspace between the two layers of plastic (a sheet on the top and another on the bottom of the roof/poles) and allows the sun’s rays to penetrate creating a warm, stable environment for plant growth.
This earth-sheltered greenhouse taps into the thermal mass of the earth, so that much less energy is needed to heat up the walipini’s interior than an aboveground greenhouse. Of course, there are precautions to take in waterproofing, drainage and ventilating the walipini, while aligning it properly to the sun — which the manual covers in detail.
Best of all, according to the Benson Institute, their 20-foot by 74-foot walipni field model out in La Paz cost around $250 to $300 only, thanks to the use of free labour provided by owners and neighbours, and the use of cheaper materials like plastic ultraviolet (UV) protective sheeting and PVC piping.
Cheap but effective, the underground greenhouse is a great way for growers to produce food year-round in colder climates. Learn more about
At most latitudes, the temperature six to eight feet below the surface stays between 50 and 60°F. An underground greenhouse uses calm below-ground weather to keep plants growing whether it’s snowing or sweltering.
Designs for an Underground Greenhouse
Underground greenhouse. The inside can be cased in stone, mud brick or any dense natural material able to absorb large amounts of heat. Cool weather crops like lettuce, kale and brocolli can be grown during winter in harsh climates. The glazing creates a “greenhouse effect.” If your water table is high, obviously that could spell disaster. You should build your greenhouse at least five feet above the water table.
Mike Oehler’s underground greenhouse design. Mike digs a deep trench for access on the shaded south side which also allows cold air to sink and be warmed by the deeper, warmer soil. Many install tubes within the soil to transfer warmed air into the earth, yet Mike believes you need only the cold sink to allow the transfer in most climates. How to: motherearthnews. Mike Oehler’s book: The Earth Sheltered Solar Greenhouse Book.
Underground greenhouse in Spetchley Gardens, UK. Stairs down to entrance on right. Image by Mezzapod via Flickr.
During the day, the earth walls store heat. The walls are the battery that release their heat at night. A properly-designed pit greenhouse is naturally warmed at night from five sides. In an above-ground greenhouse only one side, the floor, is heated during the day. A waterproof barrier extending along the periphery and down the berms are necessary. Here are a couple of earthbag underground greenhouse plans.
Care must be taken waterproofing, draining and ventilating the greenhouse. The most efficient pit greenhouses have south-facing windows. The north wall stores heat.
This earthen-walled underground greenhouse has lots of natural clay to absorb heat. The two most important factors in a pit greenhouse are the large amount of thermal mass (stone, soil, water), and its positioning toward the sun. Via organica.net.pl
Must-Haves For Greenhouse Owners
- Black Gold 16-Quart All-Organic Potting Soil
- Roots Organics Potting Soil, .75 cubic feet
- Foxfarm Ocean Forest Soil, Smart Naturals, 1.5 cubic feet
Seedling Heat Mats
- Hydrofarm 9″ x 19.5″ Seedling Heat Mat
- VIVOSUN 10″ x 20.75″ Durable Waterproof Seedling Heat Mat
- Garden Nova 10″ x 20.75″ Seedling Heat Mat
17 Incredible Underground Greenhouses Around the World
An underground greenhouse is called a walipini in South America, from the Aymara Indian language, meaning “place of warmth.” As you dig, you save your upper-most topsoil to serve as the bottom of the greenhouse. Use the deeper soil as the new berm on the north side (or south side if you’re south of the equator). Angling your window 90 degrees to the sun on the winter solstice will allow the pit to store the most heat during those days when the sun shines the fewest hours.
1) Walipini From LaPaz, Bolivia
Here is a large walipini in LaPaz, Bolivia. At two minutes they go inside the walipini, at four minutes they walk around the outside. In Spanish. Obviously they do not get much rain there.
2) Pit Greenhouse Made With Local Stone
An underground greenhouse made of local stone in Nepal at almost 10,000 feet altitude, where the temperature falls below freezing 199 days per year.
3) Underground Greenhouse In Mongolia
This pit greenhouse in Mongolia is currently producing food during three seasons of the year. As the footprints show the entrance is on the opposite side.
4) Pit Greenhouse With Good Insulation
Inside of above pit greenhouse. In a cold climate, the north, east and west walls should be well insulated. The north ceiling should be well insulated as well.
5) Start Of A Homestead Walipini
We got the old root cellar dug back out this week. I am so excited for this project! This is going to become my underground greenhouse! #ProjectLife #UndergroundGreenhouse #Walipini #RootCellar #WeBeDiggin #CrazyBackyardProjects
At this homestead, the owners are beginning to dig for their underground greenhouse. Using the excavator will help cut down on the time it takes to finish the structure.
6) Underground Greenhouse From Tennessee
A greenhouse built into a hill in Tennessee.
7) Walipini From Sandstone In Texas
This pit greenhouse is in Texas, it is essentially a hole dug into the ground. Here the soil was such hard sandstone, minimal wall support was necessary. The picture was originally listed at https://taroandti.com.
8) Patagonian Underground Greenhouse
Earth-sheltered greenhouse with earthbag walls in Patagonia. Note the use of plastic around the periphery.
9) Walipini From An Earthen Embankment
Earthen embankment greenhouse below ground. All year growing solution for cooling climates. #grandsolarminimum #miniiceage #adapt2030 #littleiceage #earthchanges #daviddubyne #globalcooling #earthengreenhouse #greenhouse #coldclimategardening #gardening #undergroundgreenhouse #coldclimategreenhouse
An underground greenhouse can help naturally insulate crops, enabling gardeners to harvest all year around.
10) Pit Greenhouse From An Old Missile Silo
A Nebraska couple turned an abandoned missile silo into an underground home. The walls are two feet thick—four feet thick in some places. The place where the missile was held is now the couple’s garage. They’ve covered the ground with wooden flooring and plastic turf. Their underground greenhouse is the only place where natural light comes through. In the (massive) greenhouse they are able to grow tomatoes, garlic, potatoes, and green beans.
11) Walipini With A Drainage Ditch
Digging a shallow drainage ditch around the perimeter of the greenhouse will lead the run off water away from the structure. Via darfieldearthship.com
12) Pit Greenhouse
Pit greenhouse. Many underground greenhouse owners store barrels of rainwater at the back of the greenhouse to soak up and store even more heat. Note the entranceway to right.
13) Installing A Walipini Roof
When you are deciding on materials, don’t forget to consider your areas climate. Choosing the wrong material could cause the roof to collapse and kill your crops.
14) Pit Greenhouse With Old Windows For A Roof
Photo by Katherine Jensen / Flickr (Creative Commons)
Walipini is another name for a pit greenhouse, this one is topped with old windows.
15) Hand-Dug Underground Greenhouse
See step-by-step photos of a greenhouse in New Mexico dug by hand!
16) Pit Greenhouse Made By Simple Ground
This man, from Simple Ground, shows us his underground greenhouse. He says that they were able to save money by bending the galvanized steel themselves. Their plan is to use aquaponics for the plants inside, he even shows the start of their fish pond inside. He describes the purpose of the underground greenhouse, and how it regulates the temperature to help plants grow all year around. They haven’t started growing anything yet, only because they finished building at the end of fall.
17) Walipini Built In Ladakh
This mud brick walipini in Ladakh which produces food year-round in a very harsh climate.
Many More Uses for Your Underground Greenhouse
This amazing couple turned an old gunite pool into a ‘closed-loop food-producing urban greenhouse.’ The greenhouse houses tilapia, chickens and hydroponic vegetables and fruits.
An easy way to warm up and bring light into your basement. Build a mini-pit greenhouse on the south side of your home. naturalbuildingblog.com
A pit greenhouse used as dining area.
A pit greenhouse for musicians.
Part 1 of a video series about the construction of an underground greenhouse, by Homesteadonomics. The builder says he’s doing it to extend his growing season, because he lives in an area with high winds, and because it seems like a cool project. He gets about 60% of the digging done by hand, a backhoe finishes the rest. Then he built a rough stairway, and poured a concrete footer. At the end of the video he does a nice job of showing what’s next. As of writing he’s in the middle of building; now he’s up to part 5.
At the New Alchemy Institute bioshelter, fish tanks and compost heat the greenhouse and adjoining house. Water is dense and holds heat even better than rock, soil takes third place in heat storage. The solar aquaculture ponds are above-ground, translucent tanks. The fertile pond water was used for irrigating crops.
Driftless Farm Greenhouse by Roald Gundersen, Wisconsin. The larger you build your pit greenhouse the more efficient, as the temperatures inside of a small greenhouse can fluctuate quite quickly.
Driftless Farm Greenhouse, Wisconsin. A 2800 s.f. straw-bale insulated solar greenhouse. The , a fast-growing, sturdy and rot-resistant tree that’s abundant throughout Wisconsin.
Earth Sheltered greenhouse by Hiroshi Iguchi, Japan. A greenhouse that obviously does not completely close. Via fifthworld-inc.
Greenhouse by Rob Stout, New Mexico. swsolardesign.com.
Pit greenhouse attached to a home. Via solarinnovations.com.
Semi-underground greenhouse surrounded on two sides with a stone wall and earth behind. Via solarinnovations.com.
This incredible “Greenhouse in the Snow” is in western Nebraska, close to the Colorado border, and when the video was filmed (early December) it had been 1 below zero the day before. Yet, in the greenhouse, lemons are ready to pick. Inside the greenhouse the temperature was in the high 70s during the day, and only fell to 38 F at night. Tomatoes were growing.
The greenhouse is 80 feet long, 16 feet wide, and 12 feet high. Russ Finch, the owner of the home, says, “the entire energy cost for the year is $600.” The video shows a lemon tree so lush, they have to prop up the branches to keep them from crashing. He also grows sweet Meyer lemons. He shows a Valencia orange tree, a peach tree, roses, papaya, grapes, kiwi, figs. He grows a lot of cactus, too. The heating system is entirely geothermal, his only heating system is a small unit that circulates air heated by the ground.
Greenhouse built into a hill. Via solarinnovations.com
Pit greenhouses attached to stone buildings are also extremely energy efficient! See inside here: solarinnovations.com.
Straw bales are a great insulator (an R-value of 1.5 to 3 per inch). Manure below ground will also help to keep these plants warm. Photo by Terrie Schweitzer, via flickr.
Cold frame of old windows and straw bales. Placing manure or compost down below the layer of topsoil will help keep the area warm.
How to Build an Underground Greenhouse: Resources
Great step-by-step guide to building an earth-sheltered greenhouse with center work space/cold sink.
An underground greenhouse in Bozeman, Montana. As you can see in the video, there’s snow on the ground there. But in this completely underground unit, he’s growing peppers, radishes, chard, cilantro, basil and zucchini. He mentions that one day, even though it was 28 F outside, it got up to 117 F in the greenhouse (he forgot to throw open the doors). There is no outside heating, just a series of water barrels that help retain heat.
The partially-submerged YMCA Solar Greenhouse in Blacksburg, Virginia.
A clearinghouse of info on solar greenhouses from L. David Roper.
Mike Oehler’s Earth Sheltered Greenhouse.
Photos of underground greenhouse construction in Kyrgyzstan.
How Joseph Orr built a mud heat-storage solar greenhouse that even heats an adjacent room.
A step-by-step look at building a cinder block underground greenhouse.
Photos of a bermed, solar-heated greenhouse in Southern Idaho.
Step-by-step construction photos of a small, earth-sheltered greenhouse.
Step-by-step instructions and designs for a . You’ll need a lot of land for this one.
If you’re okay with this, here’s how to build a greenhouse that’s heated by an adjacent chamber of compost.
What life is like at the Solviva greenhouse, where it’s 4 degrees outside but, inside the greenhouse, you can be plucking fresh tomatoes in 75-degree heat.
Best Books on How to Build an Underground Greenhouse
The Earth Sheltered Solar Greenhouse Book by Mike Oehler
Solviva: How To Grow $500,000 On One Acre by Anna Edey
The Winter Harvest Handbook: Year Round Vegetable Production Using Deep-Organic Techniques and Unheated Greenhouses by Eliot Coleman
Solar Greenhouses Underground by Daniel Geery
The Solar Greenhouse Book by James McCullagh
Gardener’s Solar Greenhouse: How to Build and Use a Solar Greenhouse for Year-Round Gardening by Ray Wolf
More Underground Greenhouse Resources
National Center For Appropriate Technology: Learn about slope, orientation, glazing, etc
Solar Greenhouses: Lots of info here by L. David Roper!
Compost heated greenhouses: Provided by the National Center For Appropriate Technology
Cedar Built Greenhouses: Wood greenhouse kits, they will make a kit for your foundation
Build It Solar: For other solar greenhouse links
Underground Greenhouse Video
(This is part 1 of 34 (so far)!)
An Underground Greenhouse? It’s Not Just A Fad
Image source: Treehugger.com
As more people become aware of the importance of growing their own food, social media has become a primary way ideas are shared. One of these ideas which is often seen on Facebook and Pinterest is the walipini underground greenhouse.
This greenhouse claims to grow food year-round and only cost $300 in building materials. For lots of gardeners, particularly those in cool climates with short growing seasons, a greenhouse is almost a must-have. Let’s take a look at the advantages of an underground greenhouse:
Takes advantage of thermal mass. When you dig down even just four feet, the temperature changes dramatically. Frost lines generally are three to four deep, so a six to eight foot walipini is completely protected from frost. One walipini owner claims that his greenhouse keeps pretty steady 70 degree Fahrenheit or warmer temperatures when it’s 10 degrees outside. Because underground greenhouses are warmed by thermal mass on all sides, you really can’t lose any warmth compared to a traditional greenhouse.
Effective in almost any climate. Walipini and other pit-style greenhouses are effective nearly everywhere. In fact, many of the early designs for these greenhouses originated in very cold climates like Canada. Of course, you won’t be able to get super-hot temps in a cold climate in winter, but it will get warmer than a traditional greenhouse. Many countries outside of the United States swear by these designs, particularly gardeners in China.
More visually appealing – and hidden. While this is a matter of opinion, most people do agree that underground greenhouses are far more appealing because they don’t take up as much visual space on their landscape.
Get Delicious, Nutrient-Dense Heirloom Seeds Here!
Walipinis built into a natural slope are difficult to notice at all from a distance. Aside from the outside perspective, many people prefer the very natural look of the inside of an underground greenhouse.
Story continues below video
Versatile in its use. Obviously, the purpose of a greenhouse is to grow produce, but underground greenhouses are also an alternative way of keeping (at least some) livestock. Some people might build a very large walipini with room for goats, sheep or chickens. Others might dedicate a whole building just for livestock. In winter this can be especially beneficial for cold-sensitive livestock. Walipinis really have the same advantages of an underground home.
Doesn’t require much maintenance. Traditional greenhouses are completely exposed to the elements, which means the building material gets worn down more quickly. The only exposed area on a walipini is the roof and perhaps some beams within the structure. Garden beds are completely protected from rain, so they will last much longer.
New Natural Fertilizer Doubles Garden Production!
Many owners also find that their watering and weeding time is cut in half. Weed seeds will have a more difficult time getting into your plants from outdoors, plus the dirt you’re using is completely virgin. Walipinis tend to hold humidity and soil moisture well, so watering generally doesn’t have to happen as often.
Protection from chemicals and pests. A HUGE advantage of underground greenhouses is the fact that it is nearly impossible for most chemicals and pests to get on your produce. If you live in an area that sprays pesticides, you won’t have to worry about wind carrying them to your plants. Similarly, pests like insects would only be able to enter through the open door of the greenhouse or on your clothes. Deer and rabbits obviously wouldn’t have access, and neither would domestic pests like cats, who like to use gardens as litterboxes.
If you have easy access to earth-moving equipment or a group of people who are interested in helping you dig, underground greenhouses are definitely a viable option in most circumstances. While they differ quite a bit from traditional greenhouses, their effectiveness isn’t inhibited.
For more information on the walipini $300 greenhouse, check out . Here is another person’s take on walipini greenhouses with some very interesting “hacks” to improve the design.
Do you have any underground greenhouse tips? Share them in the section below:
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The thought of growing trees heavily laden with nectarines, peaches, figs and even persimmons in northern climates seems the stuff of fantasy. Yet, by constructing a greenhouse deep enough to utilize the earth’s consistent temperature, it’s possible to grow sub-tropical plants without an additional heat source in regions where sub-zero temperatures are common.
In-ground greenhouse design is not new. It dates back to the late 1800s in this country, but fell out of favor until recently. Homeowners have rediscovered it as they look for ways to provide more of their own food without relying on outside sources.
Over 35 years ago, John Hemighaus wanted to see what was possible to grow in an in-ground greenhouse. Fueled by a keen scientific mind and plenty of muscle, he built his private passive solar greenhouse called the Ott-Kimm Conservatory. It boasts a Zone-8 climate in the Zone-4 area of Montana’s Gallatin Valley. “I did this for my own research and study, and to feed my family,” John said. He hand-dug the greenhouse with a base 5 feet below the ground’s surface, and poured 6-inch-thick reinforced concrete walls.
Within the greenhouse, he created an enclosed ecosystem. Pacific Northwest tree frogs are one of the tiny predators that keep insect levels in check, and the natural cycle of plants, fungi, bacteria and insects maintains the soil balance. His experiment and labor of love worked like a charm. “If it’s done properly, it will feed a modest family in perpetuity,” he said.
After graduating with an ecology degree, Zach Weiss of Bozeman knew he wanted to help people grow their own. The realization of what could be done without creating an energy- intensive setup took shape when he worked with John in the conservatory.
“That’s the place where I learned 80-percent of my greenhouse knowledge,” Zack said.
He now uses his been-there-done-that experience to create sustainable food systems through his business, Perpetual Green Gardens. He builds in-ground greenhouses for clients, as well as providing Sepp Holzer-style permaculture and earthworks services to create perpetual foodscapes.
Anatomy Of A Geo-Greenhouse
The size of an in-ground greenhouse is an important consideration. Having adequate air volume matters because small spaces heat and cool too quickly. There’s also not enough area to maintain a viable population of beneficial insects.
“It’s nice to have 600 square feet or more,” said Zach, particularly if you’re trying to create an ecosystem within the structure.
The cost of the structure depends on the materials and level of manual labor. It can be dug by hand, although a backhoe or excavator makes much faster work of the project. The price depends on whether you have the capability to rent one and do it yourself, or whether you hire out the project.
What to use for walls within the ground is the next consideration. Pouring concrete walls reinforced with rebar on a proper footing is a feasible method in any part of the country. It’s also the most expensive.
Depending on the cost of concrete in your area, as well as the size of your walls and depth of the greenhouse base, pouring concrete might cost between $3,000 and $7,500.
Earthbags, which are solid-weave polypropylene bags (picture a sandbag), are another option, particularly if you have a fair amount of time and manpower. Depending on the height of your walls, you might need 1,500 to 2,000 bags for a 600-square-foot greenhouse. Subject to your location, Earthbags cost between $150 to $250 per thousand bags, so you can buy these basic materials for a few hundred dollars. The fill is free since you’ll use what you excavated from the green- house base. It just takes a whole lot of time and effort to fill and stack them.
For Earthbag construction, Zach adds rigid foam insulation to the exterior. He coats the bags with cement on the interior to prevent UV rays from degrading them.
“You can also use ICFs made from 85% recycled material‚” said Zach. With an insulation value of R20, the recycled forms are efficient and don’t use as much concrete as solid poured walls.
The greenhouse base can also be constructed with cinder blocks, brick, native stone or any other building material used for below-grade construction that will safely hold up the sides of the excavated earth. A French drain around the base is necessary to channel water away from the walls to keep the greenhouse from flooding.
Hoops Or Wood Frame?
To build the above-ground frame, you can use metal hoops, such as those used in high tunnels or hoophouses, or you can build a wooden frame.
Coverings range from 6-mil green- house plastic to solid panels, glass, or a combination of materials. Use what you can afford or what you have on hand. Incorporating tilt-out windows is highly beneficial since heat-activated window openers can be lifesavers during the hot months.
Zach prefers Solexx greenhouse panels for the glazing. “These double-wall, flexible polyethylene panels make sense in harsh climates.” he said.
In his greenhouses, Zach uses entirely passive ventilation. He has no fans or electricity. Heat-activated venting arms along the ridge of the greenhouse allow the hot air to escape, which creates negative pressure in the greenhouse that draws air in through earth tubes made of 4-inch perforated drainpipe.
“Earth tubes are a very simple concept,” Zach explained. “Air flows from outside through the tube underground below the frost line, then into the greenhouse. While passing through the earth, the air is gaining or losing heat depending on the season. In the winter, the temperature of the earth warms the incoming air; in the summer, it cools it. Nature provides its own heating and cooling system.”
Below the frost line, the earth maintains a constant temperature. This temperature is the mean annual temperature for a given location. For most places in the U.S., it ranges from 50 to 65 degrees Fahrenheit.
Zach emphasized the importance of using perforated pipe. “Moisture will condense in the tubes when hot humid air is drawn underground and cools, releasing water vapor. If you use pipe that is not perforated, this moisture builds, mold grows on it, and then you get all sorts of fungal problems.”
Growing Good Soil
When John built his conservatory one of the things he wanted to learn was how long it would take for the soil to collapse—to lose the nutrients and minerals—because he wasn’t bringing in outside amendments, as is the standard practice for most gardens.
By allowing the mix of vegetation within the structure to mimic the natural cycle of life and death, he discovered that the nutrients were renewed. Fruit dropping to the ground feeds bacteria, and falling leaves and tree prunings serve as mulch. The native rocks placed along the perimeter of beds react with the acidic rainwater, which he uses for irrigation instead of well water. Zach explained the benefits, “The acidic rainwater breaks mineral bonds in the soil and rock used for the beds. This de-mineralization, triggered by rainwater, releases manganese, calcium, iron and other important compounds into the soil in a plant-available form.”
Zach is following the same path. Using the topsoil from the site to start the beds, he creates more soil without bringing in anything additional.
“The first thing we want to do is to build soil,” he said. He has a poly-culture of plants with various growth habits and root depths. The clover fixes nitrogen in the soil, the corn roots reach deep in the soil to draw out nutrients and other plants add biomass that will increase the organic content.
Among the mix of soil builders, Zach has vegetables, herbs and fruit trees growing. And, just like many gardeners, he was concerned when an over-abundance of aphids started feeding heavily on the plants. Zach says he sprayed nothing, not even essential oils or organic pesticides, on the aphids to reduce their populations. Nature needed to take its course.
So when he noticed tiny worms in the greenhouse, his initial thought was that they were some other type of pest.
“They were actually the young stage of hoverflies,” he said. “First they got the aphids on the ground, and then hatched out and took to the air, devouring the aphids on the plants.” Now the number of aphids in the greenhouse is well within balance. They don’t do significant damage to any of the plants yet provide food for the natural predatory insects.”
Part of mimicking the natural cycle is capturing the rain to water the plants. John said that if he waters his acid-loving plants, such as blueberries, with the well water, they will be dead in short order. Montana soil leans toward the alkaline end of the pH spectrum, and watering with well water compounds the situation. Rain catchment systems on both greenhouses include one or more 1,500-gallon water tanks. Zach estimates that he needs 3,000 gallons of rain to make it through the dry months of summer, when he might not see any precipitation. In 2013, John saw only 4 inches of rain until the end of August.
“Humidity is a big part of the water,” says John. Plants take up water through their leaves as well as their root zone, reducing the amount required. John uses roughly 250 gallons of water per week, which is minimal, considering the amount of vegetation and extreme heat of the summer.
Both systems require a dormant period of two to three months during the winter. Some fruit trees require the chill period to produce, and the cold helps to keep insect populations in check. Many winters they must open the greenhouses to allow in enough cold air to chill them and create frost.
By using the natural temperature of the earth it is is possible to create a fruiting oasis even when the weather doesn’t cooperate. “If we think ahead and partner with nature rather fight it, we can create viable healthy ecosystems that are perpetually productive,” said Zach.
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The idea of an underground greenhouse suggests a bleak future where growing plants above ground is no longer feasible – right? Maybe not. Underground gardening can extend growing seasons by a month or two, or even allow for year-round planting if you’re up for putting in some real effort. Read on and find out how it’s done.
There are various options for underground gardens and all make use of the fact that soil has thermal mass. In other words, it can absorb heat and slowly release it. This prevents temperature fluctuations because the excess heat of the day is absorbed, and released overnight. This process can even work in winter by using a south facing window to capture the heat of the sun.
The Pit Greenhouse
An underground or pit greenhouse is buried six to eight feet into the ground and covered with a glazed roof. In the Bolivian mountains, farmers use them to protect crops from the high altitudes and harsh weather. These walipini as they’re called (meaning place of warmth) are a lifeline to farming communities, allowing them a reliable source of income to provide for their families.
A traditional Bolivian walipini
A normal greenhouse wouldn’t last long under the strong winds and high UV rays of the Bolivian mountains. But these buildings are perfectly suited to their environment and blend seamlessly into the landscape.
So why build an underground greenhouse in your garden? For one thing, running costs are lower because the soil’s thermal mass reduces the need for heating in the winter. Also, building costs are significantly less than an actual greenhouse. Of course, there’s a bit of effort in the initial construction, and some important points must be considered before you head out the back door, spade in hand.
Don’t Forget Your Shovel…
First things first – as with all building projects, location is key. If you’re in the northern hemisphere, the roof needs a decent slope to make the most of the winter sun. Otherwise the roof’s angle will be too low for the sun to reach your plants for much of the winter.
Checking out the angle of the winter solstice sun will help you work out where to position your roof. Then you can raise the north side of the roof to create a south-facing slope. However, it’s not advisable to build into a hillside because downward pressure from the soil will make supporting the walls more difficult.
This pit greenhouse is entered via an adjoining shed and fits nicely into the surrounding landscape
The depth of the water table is the second important consideration. You’ll need to build at least five feet above this – so considering the height of the greenhouse, water table depth should be eleven to thirteen feet at least. Water table depth can be difficult to ascertain as it can fluctuate from year to year. In Ireland you can contact Geological Survey Ireland for help and advice.
It’s also a good idea to check for gas pipes or electricity cables before you dig. You can contact Gas Network Ireland’s Dial Before You Dig service on 1850 427747. For the ESB Network’s service call 1850 928960.
Drainage & Ventilation
Drainage is crucial. You should fill the bottom foot or two of the greenhouse with large stones, then smaller stones, and finally topsoil. The floor should be sloped slightly from the centre to either side. At each side of the building, a gravel filled sump (with a removable lid to allow for manual removal of excess water) will allow for internal drainage.
External drainage is also important, so the berm (the raised bank of earth supporting the north side of the roof) must have a steep enough incline to move water away quickly. The berm may also be covered with a layer of plastic sheeting to help the process along. This rainwater can even be collected for use inside the underground greenhouse.
Finally, you’ll need to support your walls and allow for ventilation. Traditional walipini use rammed earth for support; a gentle backward incline from bottom to top to discourages crumbling earth from caving inward.
Rammed earth is a traditional building method in which a damp mixture of earth is compressed into a frame or mould to form a solid wall. However, it’s best for soils with less than 15% clay and higher amounts of sand or gravel. Ireland’s clay-rich soils make cob construction a more suitable method for supporting the walls. There are plenty of video tutorials on YouTube that will take you through either of these methods.
The Earth-Sheltered Greenhouse
If the Walipini-style building is too big for your garden, the earth-sheltered greenhouse, designed by Mike Oehler, may be a more suitable option. Oehler was an American author and designer of sustainable alternative housing who died in 2016. He wrote the book on underground gardens, literally!
Motivated by a desire for fresh greens (which grew for just three months of the year in the cold Idaho climate where he lived), he eventually published The Earth Sheltered Solar Greenhouse Book which is full of plans, advice and wisdom gleaned from his own adventures in gardening.
As with the pit greenhouse, Mike’s design includes a south-facing sloped roof to make the most of the sun on shorter autumn and spring days. At three feet wide, the growing bed is comfortably accessed from the walking platform. The cold sink below the platform allows the coldest air to spill down below the plants where it is warmed by the earth.
Mike recommends using upright posts (buried ends wrapped in plastic), lumber shoring behind the posts and a protective layer of polyethylene sheeting between the lumber and earthen backfill. The posts need to be buried one and a half to two feet down so that they resist lateral pressure from the soil. The roof beams support the upright posts at their top ends.
Air vents at the front of the greenhouse between the window and the soil, and in the back of the greenhouse just above the earth berm, will allow for ventilation. As with the pit greenhouse, you can also collect rainwater from the roof.
The Growing Pit
If your garden is small, another option is a growing pit. This is a hole about two to three feet deep, filled first with a layer of manure or compost, and then with topsoil, leaving a space just below ground level for growing. The compost layer below the topsoil will keep your plants warm.
The pit should be covered with glazing and packed around the edges with soil or straw as insulation; an old window or sheet of perspex will do the job. On sunny spring days the window can be propped up at an angle to catch the winter sunlight, remaining closed for colder days and frosty nights. Your plants will benefit from a greenhouse effect with minimum cost and effort.
An underground garden will protect your plants from spring frosts and snow
In his quest to extend his growing season, Mike Oehler discovered that farmers used these pits in years gone by. He tried it out himself prior to designing his earth-sheltered greenhouse, and found it reasonably successful. It’s a relatively simple method that will extend your growing season by a month and
save you from much anxious weather forecast checking and wondering if you’ve planted too early.
So, there you go – three methods for building an underground greenhouse, all of which will increase your growing season and output. And if you’re looking for something weird and wonderful to plant, check out our guide to fascinating fruit and veg.
HOW TO: Build a Stunning Underground Earth-ship Greenhouse
The Underground Earth-ship Greenhouse
This project is amazing, I always wanted to build an underground Earthship greenhouse in my garden and this company have made it a reality. Check out how to build this using their guide over at www.greenhouseofthefuture.com
So What’s the Appeal in Building a Greenhouse
I love this greenhouse idea. Unfortunately I haven’t yet had the time to build one myself, however the thought of growing fruits and other sought after goodies all year round sounds very appealing, not to mention, after a hard day’s work, lazing around in a hammock in my semi-tropical climate at the bottom of the garden would be heaven.
I can’t wait to build one of these underground Earth-ship greenhouses for next to nothing apart from my own hard labour.
How does an Underground Greenhouse Work?
It basically works by using the sun’s energy to build heat then being sunk in the ground gives it great insulation keeping the heat in. The other benefit is ‘thermal inertia’ where the subsurface temperature is constant all year round
I came across this Walipini and straight away knew I had to learn more about its building processes.
This type of underground greenhouse makes it possible to grow those fruits you had always desired, even in colder climates like here in the UK.
Who’s makes these Greenhouses?
The company behind these genius plans call this Earthship ‘The Greenhouse of the Future’.
The DVD available shows you every process of the build, included is the 70 min long movie, 200+ Ebook, The Plans and much more. You will learn things like;
- Power from the sun
- Earth tubes
- Thermal mass
- Rainwater Collection
- The use of natural, recycled and up-cycled materials.
- This video is loaded with very helpful material.
A detailed Guide
This is an extremely comprehensive guide and even if you choose to use the materials in a completely different way this guide still provides all of the research needed to enable you to understand each stage of the greenhouse build process.
If you’re as passionate about building an underground Earthship greenhouse, I would love to see what you come up with please share your creations.
Another great resource Permaculture.co.uk
Morell Court in Rivett is a very conventional cul-de-sac in a very conventional Canberran suburb – except that it has a very unconventional house at the end. Peter Bullen has spent about $800,000 building a home that’s underground. The garden’s on the roof and he lives down below. From the street, you would hardly know it’s there (unless he’s digging bok choy on the roof or picking broad beans). It looks like an empty plot – but go down the slope of the drive and knock on the door below street level and you’re ushered into a different world. Bedrooms, bathroom, workshop and kitchen are all encased in concrete walls sunken into a hole, covered with a concrete roof on which sits a garden for 230 plants. It feels like a man cave but he says it’s very comfortable – and very practical. And interesting, so interesting that the Grand Designs programme will feature it later in the year. “I wanted maintenance-free. I wanted it to be energy efficient. I wanted a big garden but I didn’t have a big block,” he said. He also wanted a workshop where he could operate an angle-grinder in the middle of the night without disturbing the neighbours – and a buried room provides that. So he designed exactly the right place for his needs and desires. It’s the last house he’ll ever have. “They’ll take me out in a box on this one.” He had been thinking about it for for five to eight years. The whole idea is simple. The walls were cast as concrete and brought in slabs on a truck and lowered into the pit by a crane. The concrete roof was then put on and 350 tonnes of earth put on top for the garden. The earthen garden was surrounded by stone slabs from a quarry in Wee Jasper. He’s now planted broad beans in the overhead garden (which he is dismayed to find have been attacked by bowerbirds – “vandalised” he says). In general, though, the plants are meant to be bird-friendly. There are smaller, thorny shrubs, for example, meant to provide a refuge for smaller birds hiding from larger thorn-averse ones. “I like trimming hedges. It will be a haven for birds.” Ultimately, he wants to turn the roof-top garden into a kind of heath, largely with native species of plant. He is not religious about what kind of plants, native or imported – lavender will have a place. In the yard at the back, he has planted 800 small pots hanging on the wall. He and a friend are experimenting with plant types with the aim of getting them to cascade down the wall and fill the yard with colour. Indoors, there is no heating or electric cooler because the home-owner doesn’t feel it needs it. The earth above insulates it from the cold of winter and the heat of summer. There’s a sunken yard at the back, and the sun shines through the big window and heats the floor. Is there a danger of flooding? On his calculation, his pump can cope with seven inches of rain in 45 minutes – though he is thinking about a small generator to keep everything, including the pump, going if the power fails. “Once the power goes off, I’ll be in trouble,” he admits. He is a satisfied man – in his man cave. Every man’s dream.
Growing Fruits and vegetables all year round in Canada or the colder parts of North America would be wonderful but, sadly, our climate limits us to a few growing months in the summer. And even that would be in the balmier areas of our country; at high altitudes and further north it is difficult to grow any edibles without a greenhouse.
There are two main types of greenhouses to consider – those attached to a home and accessed by an interior door (which can also be used as a solarium and which are incorporated in Earth-ships with varying levels of success in cold climates), and free-standing greenhouses that are intended primarily for cultivating plants and food. In this article, we have spoken to three different owner/builders (all in Quebec but with variable climates) about the construction methods they chose and the types of food they grow.
Pierre Fisette – Estrie, southern Quebec
Pierre Fisette built his passive solar greenhouse by himself after extensive internet research and attending workshops. He began with existing greenhouse plans and adapted them to meet his specific needs & the needs of a cold climate.
The building is wood-framed, 20’ x 40’ and 16 feet high inside. The north wall is buried about 6 feet deep and made with 310 old tires that are filled with sand. The three other sides allow light in, plus the south-facing roof. The north roof is metal.
- Rigid insulation was used below the floor and on the north wall.
- Glazing is a mix of polyethene, patio doors and reclaimed windows.
At this moment, two small fans provide the necessary fresh air and moisture removal. The installation of a ventilation system powered by solar panels is planned for the future.
Growing season: At present, it is used for a little over three seasons; there are about 2-3 months where it is not currently in use. Pierre plans to add a rocket stove and geothermal heating system in the future to extend the growing period to a full four seasons.
Type of crop & yield:
No special soil was used, and it is fortified using only organic or natural fertilizer. The crop includes an assortment of greens and vegetables such as tomatoes, cucumbers, peppers, snow peas, swiss chard, kale, herbs, etc.
“Our goal is to become self-sufficient, at least as much as possible. I could grow enough to provide for several families if I wanted, but our original goal was not to make a living with it,” said Pierre. Their household has two people, but this cold climate greenhouse also helps feed four children, grandchildren and step-parents. “We give a lot of it away, and this year we began to sell some in the local village. Selling surplus helps us continue to finance the project.”
Cold Climate insulated Greenhouse construction © Pierre Fisette
Total material cost:
About $3,000 to date. The cost was kept to a minimum through the use of many recycled, salvaged and traded building materials, though Pierre expects that total to go up with the additions he has planned for the future.
Level of satisfaction:
Very satisfied. “There will always be surprises and shortcomings in a crazy project like this,” he says with a laugh, “but we’re taking care of them one problem at a time.”
“We would eventually like to add walls made of old bottles. This is about more than just food, it is also an artistic project”. Both he and his partner are artists and avid recyclers.
And on achieving his goals of self-sufficiency, he says, “We have not had to buy vegetables since the start of May. We don’t eat much meat, and the meat we do consume comes from a local organic producer.”
Pierre expects to achieve 100% self-sufficiency in terms of fruits and vegetables within 5 years, which is a fabulous result for a cold climate greenhouse.
His recommendations to others:
- Buy an existing metal structure to simplify the build!
- Be very mindful of moisture levels- it is important to avoid having plants that are soaked in water in the morning as water left regularly on the leaves can lead to diseases & mold.
Greenhouse construction © Pierre Fisette
Maude Alary-Paquette – A low-budget greenhouse in Northern, cold Quebec
Haute-Gaspésie, town of La Martre along the banks of the St. Lawrence river
This cold climate greenhouse is 10 x 16 feet, built using a repurposed Tempo Shelter metal frame. All surfaces of the walls and roof are uninsulated and glazed only with polyethylene. The floor is patio stones laid on top of a geotextile membrane. Cedar wood was used for its resistance to rot.
No ventilation system is in place apart from the windows and polythene walls which are raised during the day to bring in fresh dry air and to avoid overheating.
There is no heating system, so its use is currently limited to the summer months, from the first week of June to as late as mid-October. But the couple would like to add a heat source of some kind to extend the functional use to three seasons.
Mostly tomatoes, but also peppers, cucumbers, ground cherries, berries, herbs such as coriander and basil. A quarter of the area was reserved for green manure crops.
The greenhouse currently provides vegetables for two adults and one child in summer. “It would be possible to plant successively and grow more vegetables adapted to the cold at the beginning and end of the season, we just don’t have the time. And our growing season in Gaspésie is shorter than in southern Quebec,” Maude told us.
A few challenges were realized when they first transitioned to growing food in a greenhouse, but Maude says they adapted quickly and found many problems can be solved by regularly opening it up and allowing a change of air.
- The greenhouse impedes visits from a lot of pollinating insects, it also increases the humidity.
- Potential overheating is another factor that requires constant monitoring.
- They are vigilant about keeping it closed up at night to avoid losing the crop to local wildlife.
Greenhouse construction in colder northern Quebec © Maude Alary-Paquette
Level of satisfaction:
“We love growing our food and the autonomy that comes with it,” Maude says. “Apart from the organic farmer in the neighboring town, it’s a bit of a food desert up here in Gaspésie. I like to know what we are eating, where it comes from and that the food we consume is organic in reflection of our values. Our greenhouse will be a lifelong apprenticeship and a haven of peace!” exclaimed Maude.
Maude’s goal is to produce enough greens and vegetables to replace the organic local baskets she previously purchased. The greenhouse should be paid in about two years thanks to savings on food purchases.
Recommendations for those who want to get started with a cold climate greenhouse?
Maude first suggests taking the time to track the seasonal sun exposure to help choose the best location.
“Don’t build too big if not necessary, and do take the time to process your harvest (cooking, canning and freezing) if everything is ripe at the same time. “It’s important to learn about the types of crops you’re interested in growing, to reserve a space for green manure, to rotate crops, and so on. “
Maude also loves being able to experience the sunshine and warmth in the greenhouse even when it isn’t growing food. “It can be -15 °C outside in February but 10 °C in the greenhouse! On the downside however, in order to do that I have to keep the roof and door clear in winter … “
Laurent Teasdale & Frédéric Bachand – growing a business in a cold climate
Stanbridge Station, Southern Quebec near the Vermont border. Safrenière des Cantons is a company founded by Frédéric Bachand and his mother Sylvie Bernatchez, a family-run business that specializes in organic farming and the distribution of saffron and paprika.
In order to expand the family business, Teasdale and Bachand bought an old metal greenhouse structure from a retired farmer in the area. The greenhouse they purchased was longer than required, and therefore was split into two independent structures. One of the greenhouses is glazed with a single layer of polyethylene, the other has a double-layered polyethylene fabric with an insulating layer of air in between.
The insulated greenhouse is heated with a reclaimed forced-air furnace that is that activated automatically by a thermostat when the temperature drops below the established threshold. The heating system stops automatically when the control temperature is reached.
The sides of both greenhouses open as needed to let in fresh air. The insulated greenhouse also has a thermostat-activated fan that removes heat when the building reaches a set temperature.
Growing season: The heated greenhouse can produce for about three seasons starting as early as April. The uninsulated portion is limited to warmer months only.
The insulated greenhouse is used primarily for business purposes, growing saffron and paprika. It allows for a three-season crops and the sprouting of 10,000 annual seedlings of paprika and saffron which will eventually be planted in fields (approximately 50,000 sq. Ft.) In mid-late June.
The couple uses the other greenhouse for growing vegetables for their own consumption such as tomatoes, cucumbers, cabbages, etc.
$2500 total for both greenhouses
The greenhouse used for food production has an irrigation system with water pumped from a nearby pond. This untreated water is unfit for consumption, but perfect for gardening. The other greenhouse and the fields do not have an automated irrigation system.
Safrenière des Cantons cold climate Greenhouse © Laurent Teasdale
“We love it, because for us it’s like an extension of the house since we used to prepare our seedlings in our small attached solarium.” says Laurent.
“We did have some small issues with the furnace in the first year and sometimes the greenhouse was too cold. We have made some adjustments and are hopeful about the coming winter.”
The primary goal of the greenhouse installation was for their business expansion, but on a personal level, they aspire to self-sufficiency, at least during the summer months. To achieve this, Laurent and Frederic planted several fruit trees and they have a few head of cattle to produce their own meat. Surplus vegetables are canned or frozen, and those unsuitable for human consumption are used to feed the animals. Animal waste is turned into manure that will be used on the next year of crops.
Recommendations for those who want to get started?
“Be prepared well in advance, and if possible have the greenhouse put up before the cold weather of winter so you are ready to go as soon as the weather warms in the spring.”
“Look for used materials before buying new. It may take some time, but you can often find used green house structures online, as well as old windows and doors. This saves on costs and keeps materials out of landfills.”
“Be sure to compost!”
If you have a cold climate greenhouse project, please catalogue the build & experience and let us know about it in the comments below.
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DIY plans, videos, infographic, and info about the Walipini, an underground greenhouse that lets you grow year round. You can build it for less than $300!!
Homesteaders, farmers, and backyard gardeners often use various methods to extend the growing season, especially in colder climates.
They often use cold frames, hoop houses, black plastic, frost covers, and greenhouses to give their crops a boost or a head start for the coming growing season. They’re also used to hold off the fall frost for a few more days or sometimes weeks.
Greenhouses are the largest and most permanent of these structures. They are usually expensive to construct and require a lot of additional heat to extend the season much into the winter.
A much more affordable and effective alternative to a standard greenhouse is the walipini. This strange word comes from an Aymara Indian word for the “place of warmth”. They are also known as an underground greenhouse or a pit greenhouse.
A walipini, is an underground greenhouse with a transparent (usually plastic, but you can use glass or even recycled windows) covering that stays warm by passively soaking up the sun’s heat and absorbing the earth’s thermal energy.
These underground greenhouse were first created over 20 years ago for the cold mountainous regions of South America to maintain food production year round even in the coldest of climates, but walipini’s are now being adopted by homesteaders and gardeners alike.
Make Your Own Walipini
If you want to build your own underground greenhouse, or walipini, then get these must-read books on the subject to learn exactly how.
The classic standard on the subject –
The Earth Sheltered Solar Greenhouse Book
The new standard on underground greenhouses –
The Year-Round Solar Greenhouse: How to Design and Build a Net-Zero Energy Greenhouse
Important notes and tips for building anything underground –
The Fifty Dollar and Up Underground House Book
Walipinis are versatile structures that can grow some tomatoes and salad crops in your back yard year round, or bananas at 14,000 feet in the Andes of South and Central America. Fruits and vegetables can be grown year-round, making it ideal for colder locations.
$300 Walipini Design
The walipini technique has been used by many organizations worldwide. The Benson Institute, a worldwide food security program and its team of volunteers built a massive 74-feet-by-20-feet walipini in La Paz, Bolivia to feed an entire community. The total cost? Around $300. They published a now hard to find DIY manual on how to build one yourself.
The Walipini, in simplest terms, is a rectangular hole in the ground 6 to 8 feet deep covered by plastic sheeting. The longest area of the rectangle faces the winter sun—to the north in the Southern Hemisphere and to the south in the Northern Hemisphere. A thick wall of rammed earth at the back of the building and a much lower wall at the front provide the needed angle for the plastic sheet roof. This roof seals the hole, provides an insulating airspace between the two layers of plastic (a sheet on the top and another on the bottom of the roof/poles) and allows the suns rays to penetrate creating a warm, stable environment for plant growth.
Minneapolis-based Seasons Unity Project also builds walipini’s in places with surface temperatures as cold as -10 degrees Fahrenheit as few as four feet below ground level.
Of course, many climates are too harsh for growing healthy vegetables, fruits, and herbs outside year-round. Rather than stopping at the apparent challenge or obstacle… allows its caretaker to harvest, store, and deliver energy without generation or requirement of external energy or active energy input.
This 4-minute video features a farmer from the Comanche community in Bolivia as he explains how a walipini helps grow crops for his community even during the harsh winter.
It’s a new system for us. We can rescue the heat, and with that heat we can make a good production and we also save water. With a walipini…we can produce not only fodder (for animals), we can produce food for all the people who live here.
This video covers the basics of what a walipini is, how to build one, and you can see the general walipini design idea. This is a great beginner walipini video to watch first and serves as a nice primer for the more technical ones below.
Here is this video from February of 2017 we can see a walipini in action, full of seed flats for this years crop.
But how well do walipini’s really work? What about two years from now? How about five years from now?
Here we have a walipini after four years of production, with several modifications over time that have greatly improved it’s heat storage ability.
And finally here is yet another walipini, this one after a solid five years of constant use.
For those looking for a more technical analysis from a scientific point of view, check out this video full of data analysis and thermodynamic figures.
As you can see from these videos the walipini is a popular design that follows a simple blueprint. You can get vastly technical with it, like in the last video, or extremely simple and just dig a hole, but in essence you’re goal is to trap the heat underground for a year round crop season.
A walipini isn’t just for mountainous regions either, it’s also great for places more resembling your back yard, like the very flat and moderate climate of The Netherlands. The Creative Garden Wageningen project is working on a walipini they’ve appropriately named the Sunken Greenhouse.
Amazingly, the structure’s inside beam is a living willow tree! The roof covering was made with donated landfill plastic. They plan to grow such hot weather crops such as lemons, strawberries, peppers, and a variety of beans and herbs year round.
Wait…It’s A Greenhouse…Underground?
Yep. It sure is. But why build a greenhouse, a shelter who’s primary use is to trap the sun, underground?
First off, walipini’s and underground greenhouses in general are not fully built under the ground as the name might imply, but instead are constructed like a lean-to on a dug out area or build above an open pit where the actual gardening takes place.
Typically walipini’s uses a wall of compressed earth on one side of the building and a shorter wall on the other side. This makes an angle for a plastic sheet roof that catches the sun’s rays to create the ideal temperature for plant growth.
Ok, so why go through the trouble of putting a greenhouse partly in the ground or over a dug out pit, you ask? Simple thermodynamics thanks to the insulation properties of all that dirt, that’s why. By digging just six to eight feet below the earth, growers can take advantage of the Earth’s thermal constant.
The temperature a foot below the surface is fairly constant and with the added heat coming from the sun it makes a nice place to grow crops. Walipini’s can reach 120F inside when the outside temps are in the 20’s. But if you are in an especially cold climate you may have to add some additional heat storage so the heat will last through the night, such as covering the inside of your walipini with stone, black drums full of water, bags of lava rocks, or any dense material able to store heat.
A lot of heat energy is required to change the temperature of high density materials like water, concrete, and bricks so they act like a solar battery, storing heat during the day and releasing that heat at night to keep the crops warm.
For these reasons, typically walipini’s are at least 8’ by 12’ in size to maintain a usable amount of heat, but most are built much larger. The bigger the better when it comes to heat storage.
Other Benefits Of A Walipini Underground Greenhouse
Another benefit of a walipini is the minimal upkeep. Since they are mostly underground, only an angled roof is exposed to the elements. This makes it much easier to maintain and it’s cheaper to replace all the plastic in a few years.
While the cost of digging a pit for an underground greenhouse can be high if you have to hire someone or rent heavy machinery, since the actual structure of these underground greenhouses can be built using cut trees and saplings the costs can be kept to a minimum. If you have a tractor or backhoe, or alternatively a lot of people to help and/or soft ground, your only costs may be a box of screws and greenhouse plastic.
Planning Your Walipini Pit Greenhouse
The beauty of the walipini is its simple but effective design that can be built by anyone with a small budget and a few free weekends.
If you want to build your own underground greenhouse, or walipini, then get these must-read books on the subject to learn exactly how.
The classic standard on the subject –
The Earth Sheltered Solar Greenhouse Book
The new standard on underground greenhouses –
The Year-Round Solar Greenhouse: How to Design and Build a Net-Zero Energy Greenhouse
Important notes and tips for building anything underground –
The Fifty Dollar and Up Underground House Book
Although walipini’s require minimal effort to maintain, it is important to be thorough with your initial planning and design or they will completely fail. Properly waterproofing, draining and ventilating an underground greenhouse is extremely important and a huge topic itself far too large to detail in this post.
Also, you have to build a wailpini at least five to eight feet above the water table otherwise it will flood. Generally speaking, Walipini’s should be build on high ground and you will need to provide excellent drainage around the perimeter to keep water out. You can’t build a pit in a low lying area and expect it to stay dry, so pick a spot on high ground or expect a constant battle with flooding.
Since cold air sinks downwards, your design should include an entrance that is slightly deeper underground than the grow floor if possible to prevent warm air from exiting the structure.
Like any greenhouse, your walipini should stretch longer to the east and west and be shorter on the north and south side to maximize solar exposure.
Gutters can even be incorporated on the roof to harvest rainwater too.
Take notes from Earth Ships and underground homes that line the walls with rubber tires or black barrels to create additional insulation and heat entrapment. Incorporate ventilation vents and use the wind as a natural cooling system or your walipini will not be able to cool off on hot summer days.
If you’re interested in building your own underground greenhouse, check out this infographic with 5 things you should know:
Click To Enlarge
Walipini’s are simple to design and build (assuming you have access to a tractor or backhoe), and as long as you keep water drainage in mind there should be nothing stopping you from growing herbs, luscious greens, fruits, and veggies year round!
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