Grow Food Year Round in a Underground Greenhouse

Growing food year-round in an underground greenhouse, also known as a walipini or pit greenhouse, is an innovative and efficient way to maintain a stable growing environment regardless of external weather conditions. Here’s a guide to help you understand and build an underground greenhouse to enjoy fresh produce throughout the year.

Why Choose an Underground Greenhouse?

Temperature Regulation: The earth’s natural insulation helps maintain a consistent temperature, protecting plants from extreme cold or heat.

Energy Efficiency: Reduced need for additional heating or cooling lowers energy costs and environmental impact.

Extended Growing Season: Grow crops that typically require warmer climates even during colder months.

Water Conservation: Lower evaporation rates due to stable temperatures and humidity levels.

Steps to Building an Underground Greenhouse

1. Selecting the Site

  • Location: Choose a site with good sun exposure, ideally on a south-facing slope to maximize sunlight.
  • Drainage: Ensure the site has proper drainage to prevent water accumulation, which can damage plants and the structure.

2. Design and Dimensions

  • Size: Determine the size based on your needs and available space. A typical size is around 8-12 feet wide and 12-20 feet long.
  • Depth: Dig at least 6-8 feet deep to take full advantage of the earth’s insulation properties.

3. Excavation

  • Digging the Pit: Excavate the area according to your design dimensions. Ensure the walls are straight and stable.
  • Slope: Create a slight slope towards the entrance to facilitate drainage and easier access.

4. Wall and Floor Construction

  • Walls: Use durable materials like concrete, brick, or treated wood for the walls. Insulate them with straw bales, foam boards, or other insulating materials.
  • Floor: Install a gravel or sand floor to improve drainage. You can also add a layer of insulation below the flooring material.

5. Roofing

  • Transparent Covering: Use clear plastic, polycarbonate panels, or glass to cover the greenhouse. This will allow maximum light penetration while retaining heat.
  • Angle: Ensure the roof is angled towards the sun to maximize solar gain, typically around 30-45 degrees.
  • Ventilation: Incorporate vents or windows that can be opened to regulate temperature and humidity.

6. Insulation

  • Thermal Mass: Include materials like water barrels, rocks, or bricks inside the greenhouse to absorb heat during the day and release it at night.
  • Additional Insulation: For colder climates, consider adding extra insulation to the roof and walls.

7. Planting and Maintenance

  • Soil Preparation: Use high-quality, well-draining soil. Incorporate compost or organic matter to improve fertility.
  • Watering: Install an efficient watering system, such as drip irrigation, to ensure consistent moisture levels.
  • Temperature Monitoring: Use a thermometer to monitor and adjust the internal temperature as needed.
  • Pest Control: Keep an eye out for pests and use organic methods to manage them, such as neem oil or beneficial insects.

Suitable Crops for Underground Greenhouses

  • Leafy Greens: Lettuce, spinach, kale, and Swiss chard thrive in cooler temperatures.
  • Root Vegetables: Carrots, radishes, and beets can grow well year-round.
  • Herbs: Basil, parsley, cilantro, and mint are excellent choices.
  • Fruit-bearing Plants: Tomatoes, peppers, and cucumbers can be grown with the help of trellises and stakes.

Tips for Success

  • Lighting: Supplement with grow lights during shorter days to ensure plants receive enough light.
  • Rotation: Practice crop rotation to maintain soil health and reduce pest buildup.
  • Continuous Learning: Stay informed about best practices and new techniques for greenhouse gardening.


Building an underground greenhouse is an effective way to grow food year-round, providing a stable environment that conserves energy and resources. By following these steps and maintaining proper care, you can enjoy fresh, home-grown produce regardless of the season.

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