Ready for a little surprise quiz? Grab your #2 pencil. What is a walipini?
Is it:
A. A small, endangered fox, native to the southwest. Known for its ability to single-handedly rid your farm of vermin.
B. An elongated, eggplant-like vegetable. It’s popular in Incan cuisine and ideal for companion planting with cabbages to ward off slugs.
C. An earthen greenhouse or earth-sheltered cold frame that’s most often used to extend the growing season.
What do you think?
Well, if you answered C, you’re correct!
All About the Humble Walipini
If you answered the above question correctly, sit back for a second and bask in your own wisdom. But don’t feel bad if you picked one of the other options: you’re definitely not alone. When I first heard other homesteaders talking about walipini, I imagined an animal of some kind. Or maybe a squash—I certainly didn’t think of a greenhouse.
Walipini greenhouses certainly have a tendency to surprise people. They’re warmer than you’d expect, unexpectedly snug, and shocking in their efficiency. No-one expects underground spaces to be so warm and bright inside. But walipini are gardening game-changers, especially for those of us who live in areas with cold or unpredictable winters.
That said, they do have their limits.
If you live in the deep north, like I do, don’t expect a walipini to let you grow hot peppers in January. It’s probably not going to work that way. However, adding a walipini to your homestead could lengthen the growing season by 2-4 months. That means you could be growing hot peppers in November!
If you live in a more temperate region, your walipini really could set you up for year-round gardening. The earthen insulation and passive solar light are enough to keep your plants cozy all year long. In fact, this is true even when outdoor temperatures dip below freezing.
Place of Warmth
In the 1990s, a group of volunteers built an underground greenhouse near La Paz, Bolivia. Their goal was to stretch the growing season beyond when the nights became bitterly cold. They dug deep into the ground, well beneath the frost line. Then, they raised up supportive beams, and laid clear plastic sheeting across the top to let in light.
They called this wonderful creation a walipini. In the Amaryan language—an indigenous language spoken by the Aymara people of the Andes and Altiplano regions of South America—walipini means “place of warmth”.
During winter’s rough, surprising weather, a walipini truly is a haven of warmth and light. But what is it about a big, bright basement that’s so incredibly effective as a greenhouse? We’ll get into that, I promise. First, however, I’m going to tell you all about basic walipini design and function.
Are you ready to explore these pretty, warm places? Let’s dig in!
Earthen Greenhouse Basics
To function at its best, a walipini should follow a few basic rules. After all, maximizing warmth and efficiency is the goal here. We want the edible and medicinal plants living within to stay warm and soak up the sunlight, right?
The Right Place
First and foremost, a south-facing orientation is ideal, because this kind of walipini has a chance to soak up light all throughout the day. It may seem self-explanatory, but you’ll want to build your walipini in the sunniest spot available as well. Keep it out from under towering pines or spreading shrubs.
Remember that sunlight is your walipini’s heat and light source. The more direct sunlight it can collect, the warmer the interior will be.
Wetland Warning
Have you ever started digging and hit water? I know I have. If you strike water at any point while digging your walipini, move on. This is because one of the worst locations for a walipini is in the path of ground water.
This is because water will seep into the structure and cause mildew issues, or even flood the plants. I can’t stress enough how important it is to build a dry, waterproof walipini. After all, water damage can be devastating in any greenhouse, so take special care.
Depth
Your walipini should be sunken 6-8 feet in the ground. Basically, this is because if the submerged area is too shallow, it’ll be vulnerable to frost damage. A shallow walipini will also miss out on the soil’s natural warmth. Digging deeper will add insulation, warmth, and protection to your earthen greenhouse.
I know it can be a challenge to dig deeper than 5 or 6 feet, but keep going. If you live in a colder climate, aim for an 8-foot-deep walipini for maximum efficiency.
Design 101
These are straightforward, simple, and low-cost structures. After all, the walls are made entirely of dirt, and dirt is free!
Often, you will need to add rafters to the roof of your walipini to support the plastic roof. Strong saplings make a great, low-cost option here.
The plastic sheeting you’ll need if you’re in a temperate climate is generally quite affordable. In contrast, if you live in a colder, snowy climate, you may need to make insulating shutters for the roof. You’ll be able to close the shutters at night to keep your plants safe and warm. Then, just open them up in the morning so your plants can warm up with the sun.
The Layout
Walipinis are rectangular structures that have angled roofs to catch the sunlight. To facilitate this process, one wall is built higher than the other to hold the roof at a shallow angle. Traditionally, walipinis don’t use anything to structure the wall except soil.
The interior growing space is built up with a thin layer of gravel, covered by a top layer of soil. Inside, plants are set on top of the soil layer, usually in pots or raised growing beds.
The original designs were very specific. Walipinis were created by a Mormon outreach group called the Benson Institute, to help farmers in Boliva extend their growing season and maximize productivity. Its creators hoped the earthen greenhouse concept would help struggling farmers find a more efficient and sustainable way to farm.
They were successful in a lot of ways. While the concept didn’t exactly revolutionize growing methods in Bolivia, those who used it were impressed. Walipini designs have been migrating too! In fact, more and more gardeners worldwide are interested in reducing their environmental impact or providing fresh, local produce year-round.
These sustainability-minded growers are turning to the walipini design to make their farms and homesteads more efficient.
Efficiency
All you need to make this work are earth and sunlight. That’s it. Earth and sunlight are the simple factors that make a walipini so efficient. These sunken spaces don’t require regular heating, and they’re primarily built within the earth. The sunlight trapped by the roof creates a passive-solar heat source for the plants within.
With the help of a walipini, you could either extend your growing season year-round, or just give yourself an extra few months for those slow-growing crops.
Garden efficiency is the end goal of the walipini design: maximum results with minimal expense. If that’s something you need in your garden, take a closer look at walipini designs and see if one of them will fit your space.
Design Limitations
Since they were designed specifically for Bolivia’s climate, walipini greenhouses often need a bit of re-imagining before they can truly belong in North American gardens.
Bolivia is close to the equator, with mild weather, and direct sunlight. In contrast, this original walipini design won’t bring a lot of sunlight into an American, Canadian, or European greenhouse. This is why it’s so important to build your walipini to suit your land.
If you have crumbly, friable soil, for example, you may need to add some structural support to the walls of your walipini. In addition, if your winter nights are very cold, you may need to add insulating shutters. Up in New England, you may even need to work in a small heat source for increasingly bitter January nights.
In most of North America, you’ll need to adjust the roof’s angle to catch as much winter sunlight as possible.
Pay attention to your own unique climate and build accordingly. With a bit of adjusting, your walipini can be an exceptional garden aid.
A Walipini for Every Climate
Walipini greenhouses are designed to be low-cost structures. You can replace the plastic sheeting with glass, or add a heat source if you want to, but the ultimate design doesn’t need them.
Now, since I have a pile of old farmhouse windows and three extra woodstoves at my homestead, my walipini might look a bit different. I also live deep in the cold north, so design changes will likely be necessary.
Use what you have to make your walipini ideal for your location.
One of the best things about sunken greenhouses is their newness. If you redesign the roof to accommodate a stove pipe, or re-angle the roof to gather more light, you’re not trampling tradition. Don’t be afraid to make an impression on this efficient growing method, and make it your own.
