Here’s a comprehensive guide on how to build your own Walipini greenhouse, covering every essential step to help you create an efficient underground growing space for your plants during winter.
The term Walipini originates from the Aymara language of Bolivia, meaning “place of warmth.”
Unlike traditional above-ground greenhouses, a Walipini greenhouse uses the earth’s insulation and solar energy to maintain stable temperatures.
This type of greenhouse uses the thermal mass of the surrounding soil and is ideal for cold climates or areas with high winds, allowing you to grow plants year-round.
Benefits of a Walipini Greenhouse
1. Energy Efficiency
Leveraging the earth’s natural insulation and the greenhouse effect reduces the need for artificial heating.
2. Cost-Effective Construction
Walipinis typically cost less than traditional greenhouses since they use fewer materials.
3. Extended Growing Season
Walipinis enable you to cultivate plants year-round, even in winter.
4. Protection from Elements
Underground construction offers better protection from high winds, heavy snow, and other harsh weather conditions.
Step-by-Step Guide to Building a Walipini Greenhouse
STEP 1: CHOOSE THE RIGHT LOCATION
✅ Key Factors
1. Sun Exposure
Choose a south-facing slope (for the Northern Hemisphere) to maximize sunlight, which is essential for maintaining warmth.
2. Drainage
Ensure the site has good drainage to avoid flooding in the greenhouse.
3. Soil Type
Prefer sandy or loamy soil for better drainage; avoid clay, which retains water.
💡Tip
If a natural slope isn’t available, you can grade the site manually to improve sunlight access and drainage.
STEP 2: DESIGN AND SIZE PLANNING
✅ Determine Dimensions
🔹 Length and Width
The size of your Walipini depends on the number and type of plants you intend to grow, and your available space. Typical Walipinis are at least 20–25 feet long by 10–15 feet wide.
🔹 Depth
A depth of around 6–8 feet is common, allowing the greenhouse to capture sufficient solar energy and maintain stable temperatures.
✅ Roof Angle and Slope
🔹 The angle of the roof should be around 35–40 degrees for optimal sunlight exposure during winter.
🔹 Include vents or a rollable plastic roof for airflow during warmer months.
STEP 3: EXCAVATION
Use a backhoe or hire a professional excavation service for digging. Dig out the area based on your planned depth and width, leaving enough space for walls, paths, and planting beds.
The excavation process should create a gentle slope towards the front of the greenhouse to allow for sunlight penetration and natural drainage.
✅ Considerations
🔹 Reinforce Walls
You may need to reinforce the walls with stone, brick, or treated wood to prevent soil erosion.
🔹 Drainage Trench
At the lowest point of the greenhouse, create a drainage trench to divert water away from the interior.
STEP 4: BUILDING THE RETAINING WALLS
The retaining walls stabilize the soil around the greenhouse and prevent cave-ins.
✅ Materials
🔹 Cinder blocks, bricks, stone, or treated lumber work well for retaining walls.
✅ Construction
🔹 Foundation Layer
Lay a foundation of gravel to prevent moisture accumulation.
🔹 Wall Height
Build the walls to extend up to the soil level or slightly above ground, depending on your design.
✅ Insulation
🔹 Consider adding a layer of insulation (such as foam boards or straw bales) between the soil and wall materials for extra warmth.
STEP 5: INSTALLING THE ROOF STRUCTURE
The roof structure is a key component, as it allows light in while insulating the interior.
✅ Materials
🔹 Use a strong, transparent material such as polycarbonate panels or UV-resistant greenhouse plastic.
🔹 Consider using wooden or metal framing for added support, particularly in areas with heavy snowfall.
✅ Construction
🔹 Roof Angling
Build the roof at an angle (35–40 degrees) towards the sun.
🔹 Ventilation System
Integrate vents at the top of the roof or include a hinged panel for airflow control, as it prevents overheating and allows humidity management.
STEP 6: INTERNAL LAYOUT AND RAISED BEDS
Organize the interior for efficient plant growth and easy maintenance.
✅ Pathways and Beds
🔹 Pathways
Lay down gravel or pavers for stable walking paths.
🔹 Raised Beds
Construct raised beds along the interior to improve drainage and make planting easier. Beds should be placed where sunlight can reach them directly.
🔹 Water System
Consider installing drip irrigation or soaker hoses for easy watering, as underground greenhouses may have higher humidity, requiring regulated water management.
STEP 7: INSULATE THE GREENHOUSE
Proper insulation is crucial to maintaining a stable temperature.
✅ Options for Insulation
1. Straw Bales
Line walls with straw bales, which can be removed during warmer months.
2. Foam Insulation
Use rigid foam insulation on the walls or below ground level for long-term efficiency.
3. Thermal Mass Storage
Incorporate large barrels filled with water to absorb daytime heat and release it at night, keeping temperatures stable.
STEP 8: INSTALL A HEATING SYSTEM (OPTIONAL)
For regions with extremely cold winters, an additional heating system may be necessary.
✅ Passive Heating Solutions
🔹 Composting
Install a compost bin inside the greenhouse, as compost generates heat during decomposition.
🔹 Thermal Mass Materials
Bricks or rocks can be used in pathways or walls to absorb and retain heat.
✅ Backup Heating Options
🔹 Consider using a small, energy-efficient electric heater for extra warmth on exceptionally cold nights.
STEP 9: LIGHTING AND VENTILATION
🔹 Lighting
If sunlight is limited, especially during shorter winter days, supplement with LED grow lights.
🔹 Ventilation
Install vents or use a small fan to regulate temperature and prevent mold growth due to high humidity levels.
STEP 10: MAINTENANCE AND MONITORING
Regular maintenance is essential to keep your Walipini greenhouse in optimal condition.
1. Monitor Temperature
Use a thermometer and humidity gauge to ensure a consistent environment.
2. Check for Pests
Although underground, Walipinis can still attract pests; monitor plants and implement organic pest control as needed.
3. Adjust Ventilation
Increase ventilation during warmer months or when humidity is high.
Common Challenges and Solutions
Challenge 1: Water Drainage
💡 Solution
Ensure adequate drainage before building. Installing a French drain or an underground drainage system can help manage water flow.
Challenge 2: Snow Accumulation on Roof
💡 Solution
Use a steep enough roof angle and strong roofing material to handle snow loads. You may need to clear snow manually during heavy snowfall.
Challenge 3: Managing Overheating
💡 Solution
Integrate proper ventilation or use shading cloths during hotter months to prevent plants from getting scorched.
Recommended Plants for a Walipini Greenhouse
1. Winter Greens: Spinach, lettuce, kale, and chard.
2. Root Vegetables: Carrots, beets, and radishes.
3. Herbs: Parsley, cilantro, chives, and mint.
4. Cold-Hardy Brassicas: Cabbage, broccoli, and Brussels sprouts.
Conclusion
Building a Walipini greenhouse is a rewarding project that can give you a self-sustaining source of fresh produce all year round.
Although construction can be labor-intensive, the benefits of having a climate-controlled environment with minimal energy input are worth the effort.
By carefully planning and executing each step, you’ll have a greenhouse that will protect your winter plants, conserve resources, and provide an eco-friendly solution for year-round gardening.
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