A Deep Winter Greenhouse (DWG) is a passive-solar greenhouse for cold climates that is specifically designed to be economical and sustainable while running through the cold winter seasons of the higher latitudes.

The Deep Winter Greenhouse is a great solution for any region with a short growing season. Taking advantage of passive thermal strategies, a DWG allows growers to produce greens throughout the harsh winters, satisfying the need for year-round fresh produce with minimal energy consumption. Building on the work of Dan Handeen at the University of Minnesota’s Center for Sustainable Building Research, this model incorporates sustainable material strategies aimed at further reducing the greenhouse’s energy footprint. In addition to actively growing produce, this greenhouse serves as an educational tool for the next generation of farmers and gardeners.

How Did Greenhouses Begin?

Greenhouses historically have been used as glass structures that create an environment for plants, usually a specific crop in a specific season. This environment is designed to be ideal for the growth and production of the specific plant being tended.

Home environments are typically hobby size and used to ‘jump start’ the growing season in the spring with germinated plants and seedlings. These small houses are sometimes not economical enough to operate more intensive growing cycles during deep winter, as they are not energy efficient, and heating costs would be prohibitive. This brought about the need for a greenhouse for cold climates, also known as deep winter greenhouses.

How Deep Winter Greenhouses Work

This revolutionary concept in greenhouse design uses heat from the sun (with a south exposure) and the storage capacity of the earth (by moving air into and out of the earth) to keep a greenhouse producing even in the coldest of winter months.

The design of the greenhouse is different than a ‘normal’ glasshouse. The design of this DWG has its primary glass only on the south side. The wall is very steep and has a pitch of 60°, which is very steep.

Ideally, the north side may be earth-sheltered, as in a ‘walkout’ design. Reflective surfaces may be used on interior walls to further capture sunlight and move it to all areas of the growing greenhouse.

Also, in our ideal greenhouse, blinds (shades) will be installed and they will assist the nighttime retention of heat in the environment. Additionally, in the summer, they will help keep temperatures from becoming excessive.

The real center of this ‘system’ is the earth underneath the DWG. The earth below the greenhouse is a ‘heat sink,’ often called an ‘earth battery’. This method of using the earth is called ‘Ground to Air Heat Transfer’ or simply GAHT, , also known as a ‘climate battery.’ It is not geothermal by definition and does not use a compressor to transfer ground temperature. It is a much more simplified system. Essentially, the GAHT system involves the greenhouse heating through the sun and cooling using the soil underneath.

A few solar collectors can assist with operating the fans and small electronics, while a storage battery can be greatly beneficial for the operation of electrical at night. Backup electrical and heat must also be considered in extreme northern locations.

There are many things to consider when it comes to these types of structures, but we are here to help answer any questions or build your own Deep Winter Greenhouse! 

Benefits of Deep Winter Greenhouses

Extending the Growing Season in Cold Climates

A DWG offers a sustainable and innovative solution for year-round plant cultivation, even in the coldest climates. These specially designed greenhouses leverage passive solar energy to maintain a warm environment for plants, making them the perfect greenhouse for cold climates. One of the primary benefits is the ability to extend the growing season, providing fresh produce throughout the winter months without the need for expensive heating systems.

Educational and Community Benefits

Additionally, DWGs offer educational and community benefits, serving as a model for sustainable agriculture practices. They provide a hands-on learning environment for schools and communities, promoting awareness of renewable energy and local food systems.

Sustainable by Design

Every person relies on the planet to create stable living conditions, and part of the issues facing our world right now is due to our dependence on fossil fuels. Every step we can take to move to more sustainable sources of energy benefits us all in the long run.

DWGs are the perfect way to sync up our desire to rely less on fossil fuels, with our desire to have easy access to local, organic, and unprocessed food. The ultimate goal of the DWG is to reach a point of energy net zero. This means no additional energy is required to operate the structure, even through a northern winter! This is an incredible goal, but achievable. Overall, a DWG presents a practical approach to addressing food production challenges in cold climates, emphasizing sustainability and efficiency.

Unlock Year-Round Gardening with a Sustainable Deep Winter Greenhouse

Transform your approach to gardening and join the sustainable food movement with your very own DWG from Conservatory Craftsmen. By harnessing passive solar energy and innovative design, you can enjoy fresh, organic produce year-round, using a greenhouse for cold climates. Whether you’re an experienced gardener looking to extend your growing season or a community seeking to educate and inspire sustainable living practices, our team of skilled professionals is ready to turn your vision into reality. Contact us today to discuss how we can help you build a sustainable, energy-efficient DWG tailored to your needs.