A walipini, or underground greenhouse, offers a smart, sustainable way to grow food all year, even in cold climates. Originating from Bolivia, “walipini” means “place of warmth” in the Aymara language, and this greenhouse design makes the most of geothermal and solar energy to maintain a stable, warm environment. Here’s how to create a walipini greenhouse and enjoy fresh produce year-round.
1. Understand the Basics of a Walipini
A walipini is essentially a dug-out greenhouse with transparent roofing at ground level. The structure:
- Traps solar heat through the roof, warming the plants and soil.
- Uses the earth’s natural insulation to maintain steady temperatures.
- Can be built using affordable materials like plastic sheeting, lumber, and natural insulation.
By going 6-8 feet underground, a walipini can protect plants from extreme weather, keeping a steady temperature ideal for growing vegetables, herbs, and even some fruits.
2. Choose the Right Location
- Sun Exposure: Position your walipini to face the sun, ideally facing north if you’re in the Southern Hemisphere and south in the Northern Hemisphere. This maximizes sunlight for warmth and growth.
- Elevation and Drainage: Choose an area with good natural drainage to avoid flooding. High ground or a slight slope is best.
- Wind Protection: Position your walipini near a natural windbreak, such as a fence or trees, to prevent cold air from disturbing the greenhouse.
3. Design Your Walipini
- Dimensions: Typical walipinis are around 6-8 feet deep, with walls angled outward to support the roof.
- Roof Angle: Design the roof at a 35–40° angle to maximize sunlight exposure and help rain or snow slide off.
- Insulation: Pack the outer walls with a mixture of soil, straw, or clay to enhance insulation. You can also use thermal blankets or extra layers of plastic on colder nights.
4. Build the Structure
- Digging: Dig out a rectangular pit to the chosen depth and length. Make sure the walls slope outward to avoid soil collapse.
- Walls: Line the walls with a strong, insulating material like concrete or bricks to hold heat and prevent soil erosion.
- Roofing: Use sturdy, transparent materials such as polycarbonate panels or UV-resistant plastic sheeting to allow sunlight in. Ensure the roofing structure is durable enough to hold snow or withstand winds.
5. Ventilation and Water Management
- Ventilation: Add vents or a simple ventilation window to the roof to regulate temperature and humidity. This prevents the walipini from getting too hot on sunny days.
- Drainage Channels: Create channels along the edges of the walipini to drain rainwater away from the structure.
- Irrigation: Since a walipini is often a closed system, install a simple drip irrigation system to keep plants well-watered without over-saturating the soil.
6. Prepare for Year-Round Planting
- Soil Preparation: Fill your beds with rich, well-draining soil and compost. Regularly add organic matter to keep soil fertile.
- Cold-Hardy Crops: During winter, plant hardy greens like spinach, kale, and Swiss chard. Root vegetables such as carrots, radishes, and beets thrive as well.
- Warm-Season Crops: When it’s warmer, plant tomatoes, peppers, cucumbers, and herbs to enjoy a summer harvest.
7. Maintenance Tips for a Successful Walipini
- Temperature Monitoring: Check the walipini’s temperature daily and adjust ventilation as needed.
- Seasonal Adjustments: In colder months, add thermal blankets at night to maintain warmth. During hotter months, increase ventilation or consider shade cloth.
- Regular Soil Testing: Since walipinis can accumulate excess moisture, test and amend the soil regularly to keep it well-balanced and fertile.
Conclusion
A walipini underground greenhouse allows you to cultivate fresh food all year long, no matter the climate. By harnessing natural geothermal warmth and sunlight, you create a sustainable garden space that provides nutritious, homegrown food. With proper planning and maintenance, your walipini can become a productive, eco-friendly addition to your backyard.