How To Construct An Efficient Minnesota Greenhouse?

The best location for a greenhouse in Minnesota is in a spot with at least three hours of winter sunlight a day. Greenhouse styles range from window boxes to complete stand-alone structures, and greenhouses built on the ground require a frame, cover, and base. A Deep Winter Greenhouse (DWG) is a passive-solar greenhouse designed to limit the amount of fossil fuel needed to grow crops during cold winters. These greenhouses rely on energy from the sun to heat the structure. The guidebook highlights the successes and lessons learned by growers across the Midwest who have designed and built cold-climate greenhouses to grow produce.

Deep Winter Greenhouses use groundbreaking technologies that allow for year-round cultivation, using passive solar, low-cost, and low-carbon winter food production systems. The structure is built with a south-facing, angled glazing wall. A small experimental greenhouse also attempts to use passive annualized heat storage and annualized geo solar principles. To build an earth-sheltered greenhouse using passive solar gain, follow step-by-step instructions, including a simple and efficient structure with poly film covering, efficient heating, and lighting.

What is the most profitable plant to grow in greenhouses?

Spinach is a lucrative cash crop that can be grown in a greenhouse to protect it from the sun and sell unlimited leaves per season. Baby spinach, which grows well in a greenhouse due to its weak stems, can be served raw or steamed. Microgreens, such as basil, beets, and mustard, are nutritious and delicious vegetables that are typically sold at high prices in restaurants. Growing microgreens in a greenhouse is a lucrative business, especially if you have a ready market and can harvest them within 2 to 4 weeks.

Is a heat pump worth it in Minnesota?

Heat pumps are an energy-efficient alternative to furnaces, providing a more efficient heating and cooling system. They use electricity to pull heat from the outside air and pump it into the home, using a fan to draw air into the system and pushing it through a filter. The filtered air is then heated by gas or electric current before being blown back into the room. Heat pumps can reduce energy use for heating by approximately 50 compared to furnaces and baseboard heaters.

They can be installed in ducted or duct-free systems, with ducted systems using a duct to transport the air from the heat pump to the rest of the home, while duct-free systems use a pump and fan installed in each room that needs to be heated or cooled. This flexibility makes heat pumps an excellent choice for Minnesota homeowners.

Do greenhouses work in Minnesota?

Minnesota’s cold winters are not ideal for traditional food production, but deep winter greenhouse technology is changing this. A deep winter greenhouse (DWG) is a passive-solar greenhouse that uses sun energy to heat the building, storing heat in a thermal mass. This technology was developed to reduce fossil fuel inputs in indoor food production. In 2017 and 2018, a first-generation UMN-designed DWG was built in each of the five University of Minnesota Extension Regional Sustainable Development Partnerships (RSDP) regions, used for research, food production, and public education. The technology is a significant step towards reducing greenhouse gas emissions.

What temperature is too cold for a greenhouse?

To maintain optimal plant growth, keep your greenhouse temperature below 3C (37F). Tender plants like pelargoniums, half-hardy fuchsias, and citrus trees prefer a minimum of 7C (45F), and safest at 10C (50F). This temperature is ideal for young plants and plug plants. If you have a conservatory, use it to overwinter delicate plants. Position heaters carefully, placing them in an open, central spot away from water and angling the heater to prevent foliage desiccation by direct airflow above nearby plants.

What is the most cost effective way to build a greenhouse?

Building a low-cost greenhouse requires selecting budget-friendly materials such as PVC pipes or rebar for the frame and UV-resistant plastic sheeting for the covering. Utilize free or low-cost glazing options like recycled windows, clear shower curtains, or plastic soda bottles cut in half. Proper ventilation is crucial for a healthy growing environment, and can be sourced inexpensively from thrift stores or repurposed materials. By utilizing these materials, you can create a cost-effective greenhouse that promotes plant growth and maintains a healthy environment.

How to heat a greenhouse in Minnesota in winter?

Bubble wrap can be employed to prevent the intrusion of cold drafts into greenhouse frames, thereby reducing heat loss. UV-stabilized horticultural bubble wrap insulation has been demonstrated to provide warmth to plants and to protect rootballs from cracking. A thermometer is an invaluable tool for monitoring greenhouse temperatures, allowing for the optimization of heating systems and the reduction of energy expenditure. Additionally, monitoring air temperature is advantageous.

Do you need a permit to build a greenhouse in Minnesota?

A greenhouse exceeding 120 square feet in area is subject to the issuance of a building permit.

What is the most efficient type of greenhouse?

Twin-wall polycarbonate covers are more resistant to temperature variability and last more than double as long as poly film. However, greenhouses lose a lot of heat during winter months, especially at night. To improve heat retention, use winter-ready poly film glazing, which is heavier and more opaque, which attracts heat during the day and reflects it back into the greenhouse at night. Another option is installing a water wall for passive solar heat, which uses polyethylene bags filled with water to absorb solar energy during the day and radiate it into the greenhouse at night.

How do Minnesotans heat their homes?

Furnaces are highly efficient and reliable heating units for homeowners, providing a minimum of 15 years of service. They are energy-efficient, cost-effective to maintain and repair, and widely available from many manufacturers. However, they have drawbacks, such as high maintenance and repair costs, limited selection, and potential for fire hazards. Proper furnace services can help ensure the longevity and efficiency of your heating system.

Do greenhouses work in cold climates?

To use a greenhouse in winter, add heat through passive solar heating or electric heaters. Polycarbonate panels are natural heat insulators that can retain heat at a higher rate than other materials like glass. Look for a 4-wall construction on the roof and window panels for better heat retention. This allows for an extra few weeks in spring and fall without adding heat, saving money and plants.

For a greenhouse that requires little exterior maintenance, choose a rot-resistant material. Wood greenhouses may blend in with the aesthetics of a backyard, but they should not start to rot during the first rain or snow. By choosing a greenhouse that effectively retains heat, you can save money and ensure the health of your plants.

Does a greenhouse need a foundation?

Attached greenhouses require frost-free footers that won’t shift or move, as they can move or sag during freezing and thawing. To ensure proper foundation, local building codes determine the depth needed for footers. Some gardeners prefer a natural base with a gravel floor, which can be made of limestone gravel with a weed barrier to prevent weed growth. The footing requirements remain the same regardless of the chosen floor material.

Freestanding hobby greenhouses have fewer requirements than attached greenhouses, offering more options for foundation and floor. They can be poured without a deep foundation, placed directly on a cement slab or on a treated lumber base. A wooden base can be anchored into the ground with three foot lengths of rebar. For a freestanding greenhouse with a knee wall, a 12″ x 12″ surface footer is required to support the weight of the knee wall and prevent cracking of the cement pad. Knee walls are installed for design appeal and their natural high thermal mass, absorbing heat from the sun and acting as a passive heater at night.