Functioning Of An Inground Greenhouse?

Greenhouses work by absorbing sunlight, which plants convert into heat and release slowly to warm the air around them. This process creates ideal growing conditions for a wide variety of plants, even in snowy conditions. A walipini is a rectangular pit dug into the ground and covered with a double layer of plastic. An underground greenhouse (walipini) is an intriguing set-up that combines passive solar heating with an earth-sheltered building.

In cold climate gardens, underground greenhouses extend the growing season by providing a naturally stable environment for plants. The sun heats the air inside, which is blown underground with a fan and stored in a thermal mass made of rock or soil. This heated thermal mass acts as a heat battery and stores heat for when it is needed at night. The interior walls can be constructed from any material that absorbs heat well, such as stone, mud bricks, or any dense and sturdy natural material.

The perceived benefit of a pit greenhouse is that the earthen walls surrounding the grow space provide ample insulation. As air temperatures drop at night, the ground releases its stored heat into the enclosure, keeping the plants from freezing. Full-size pit greenhouses are partially sunken into the ground with a small portion of translucent walls and a small portion of translucent walls.

Irrigation is another important aspect of underground greenhouses. Many owners store barrels of rainwater at the back of the greenhouse to soak up and store even more heat. A comprehensive guide to building your own underground greenhouse is available, explaining the theory behind the system.

Do sunken greenhouses work?

Walipini greenhouses are effective in equatorial regions with high sun exposure and 12 hours of light per year. They have a low-profile roof to protect plants and the structure from strong winds and minimize flooding. However, these traditional designs require adjustments for regions with short winter days and low sun exposure.

Chinese Style Greenhouses, popularized by Chinese gardeners, have built 2 million acres of passive solar greenhouses. These greenhouses typically have three brick or clay walls enclosing the growing area, with a transparent plastic film covering the southern exposure. The bricks absorb and store sun heat during the day, while releasing warmth at night and protecting plants from north winds. At sunset, growers can spread an additional insulating sheet of straw or woven grasses to slow heat loss, allowing the interior temperature to be maintained up to 45 degrees warmer than outside.

What is the temperature in an underground greenhouse?

Pit greenhouses are energy-efficient, as they are essentially holes dug into the ground with an attached glass structure. They maintain a temperature of around 50 degrees year-round, which is 10 degrees warmer than an above-ground greenhouse. To maintain a 70-degree temperature, only 20 degrees need to be raised. Most plants require constant 60-degree temperatures, so pit greenhouses stabilize the temperature, reducing energy costs and allowing for year-round plant nurturing.

Plant selection is crucial, but allowing the greenhouse’s temperature to fall below 50 degrees is not recommended. Cold weather crops like kale and broccoli can grow lower temperatures, while warm weather plants like peppers and tomatoes require higher temperatures. Plants are often grown directly in the soil in pit greenhouses, but extra depth is needed for drainage and the floor is sloped to encourage water run-off.

How do you secure a greenhouse to the ground?

To ensure the safety of your greenhouse, anchor it securely, using cemented anchors for soil-based greenhouses and drilling as deeply as possible for hardstanding ones. Place the anchors evenly across all sides to distribute the load. When bad weather is forecast, take precautions to prepare your greenhouse for high wind. Protective measures include wind-proofing, replacing or repairing damaged parts, considering the type of greenhouse and its location, and ensuring the greenhouse is properly positioned. This article provides tips and suggestions on safeguarding your greenhouse and garden space, providing security and peace of mind in any weather conditions.

Do tunnel greenhouses work?

High tunnels are practical for farmers and commercial flower growers, and small-scale hobby growers can also use them. They can be free-standing structures or gutter-connected with multiple bays. Common framing materials include aluminum or galvanized steel tubing, which are inexpensive, rust-resistant, and long-lasting. Metal or wooden cross bars are attached horizontally along the sidewalls for reinforcement and stabilization. The most common covering material for a high tunnel is 6 mil polyethylene plastic, with single-layer plastic being the most common due to its light transmission and heat retention.

Double-layer plastic has better heat retention but lower light penetration. A shade cloth can be used to control temperatures or as a covering material. High tunnel plastic coverings can be applied and removed seasonally, depending on crop requirements.

Why underground greenhouses?

Building a foundation with a downward slope can help capture heat in colder months, while black water barrels can store solar heat gain during sunny days. Radiation and emissivity are crucial factors in greenhouse design, with blacker materials absorbing more light and heat. Reflecting light with white or shiny surfaces can increase brightness, spreading productive growing light. Materials like stone and metals transfer heat effectively to cool areas, while insulators can slow heat transfer to cold areas. Convection occurs when hot air rises and leaves cool areas near the ground.

Can you put a greenhouse directly on the ground?

Installing a greenhouse on soil or turf is not recommended due to potential subsidence, warping, glass breakage, weed growth, and water logging. A base is essential for many greenhouse models and can be purchased pre-fabricated or built from bricks or railway sleepers. Newer models often have a built-in base and often have a low or zero door threshold. Building a suitable base can provide additional benefits such as increased efficiency, reduced maintenance, and reduced water usage. It is essential to consider the advantages of having a greenhouse base when choosing a greenhouse model.

Where should you not put a greenhouse?

Place a greenhouse under tall trees to reduce sunlight and prevent glass damage. High walls, hedges, and trees can serve as windbreaks, providing shelter without blocking light. These barriers keep plants warm and prevent wind damage during storms. However, it’s important to ensure the trees are a suitable distance to provide shelter without blocking light. Providing ample room for cleaning and maintenance is crucial for maintaining a healthy greenhouse environment.

Does greenhouse need to be attached to ground?

Mounting a greenhouse on a base ensures stability and increases its lifespan. For a successful hobby greenhouse, it’s essential to keep the air moving to balance temperature and prevent diseases. Fans can help eliminate hotter and cooler air pockets, which can impact plant health. Regardless of the materials used, it’s crucial to have a greenhouse that meets certain non-negotiables. These include keeping the air moving to prevent fungus and other diseases, and ensuring the structure is stable and stable.

Do greenhouses need foundations?

A soil foundation is the most basic foundation for greenhouses, requiring only leveling to prevent crooked frames. It offers better drainage and allows plants to grow in it. Advanced greenhouses may include base frames and anchors for stability. Road base or paving stone is another option. Brick-paved or stone foundations look prettier but allow water to run off equally well. Concrete slabs are a cost-effective and long-lasting base level, but may require state permission to integrate due to potential hazards when used alongside overhead irrigation facilities. Concrete slabs can be installed on a property without requiring permission from the state.

Does a greenhouse need drainage?

Gardeners often prefer a solid concrete slab for their greenhouses due to its stability, flatness, and ability to withstand expanding anchor bolts. However, concrete can collect pooling water, which is not 100% waterproof and can seep under the cill or base. To ensure a free-draining base, flagstones are recommended. They are easy to secure, provide a solid level base, and require minimal maintenance. Free-drainage through the chinks between slabs prevents water pooling and keeps out potential burrowing vermin.

Using paving slabs for the foundation is not critical, but it is important to remember that the actual size of the greenhouse is larger than the nominal size, and the base size should reflect this. The base should be free-draining and always above the surrounding ground.

Should you open your greenhouse every day?

Greenhouses are designed to absorb heat, which is beneficial for plants. However, too much of this heat can be harmful. To maximize ventilation, it is recommended to leave the door wide open or ensure multiple vents are unblocked. A simple rule of thumb for greenhouse ventilation is to ensure at least 20 of the total floor area can be opened. This means that one-fifth of the floor size should be “openable”, and smaller greenhouses may need a higher percentage. This ensures that the greenhouse is well-ventilated and provides adequate warmth for plants.