Season Extension and Heat-Loving Crops
In 2023, we completed the construction of a passive solar greenhouse. This structure allows us to extend the growing season by approximately 2 months; and allows us to grow heat-loving herbs and vegetables that we cannot grow outdoors in our northern climate.
2024 was the first full growing season in our new greenhouse and we were thrilled with the results! We grew a wide variety of bedding plants in the spring for sale and for use in the market garden, and produced our first crops of greenhouse tomatoes, cucumbers, basil and baby ginger.
What’s so Special About our Greenhouse?
• Maximizes thermal storage
• Minimizes heat loss
• Passively cools and heats itself
• Needs minimal inputs of heat and electricity
These attributes are extremely important to us because the growing season in the Yukon is so short; low nighttime temperatures are a real challenge; we value passive technologies; and we strive to minimize our use of natural resources for heat and electricity while maintaining an optimal growing environment for our plants.
7 Key Features
1
Oriented 15 degrees east of south to optimize early morning sun exposure
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This also gets the nighttime chill off as soon as possible!
2
Climate battery to store free solar energy in the soil floor
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A fan blows hot air (warmed by the sun) from high in the greenhouse through a system of perforated pipes in the soil floor. This helps cool the greenhouse before the hot air needs to be vented outside. The fan also blows relatively cooler air (overnight or on cooler days) through the pipes to warm the air by the heated soil.
3
Insulated north wall to help minimize heat loss
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We prioritize heat retention over solar gain on the north wall. This wall is also painted white, making it highly reflective so that it can reflect sunlight back to the plants.
4
Thermal curtains close every night, creating a lower ‘ceiling’ and effectively reducing the greenhouse’s volume
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The curtains help retain heat so that the climate battery and/or pellet stove work to heat the area at plant level, and energy isn’t wasted heating the peak of the greenhouse.
5
Sheeted with twin wall polycarbonate
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Polycarbonate is more insulating than other traditional greenhouse coverings (such as glass or polyethylene), has a high light transmission value, and is very strong and durable.
6
Passive ventilation
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The side wall and roof vents open at the same rate as needed, so that hot air exhausts through the roof and draws cooler air in through the side wall. We also open the doors on the end walls on hot days to cool the greenhouse without the use of exhaust fans.
7
Pellet stove to heat the greenhouse as needed
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It was important to us to choose a renewable fuel source rather than relying on fossil fuels to heat the greenhouse.
Thank You’s
Our passive solar greenhouse was a major project, in the works since fall 2021. It would never have been possible without the overwhelmingly generous support that we received from funders, key in-kind contributors, volunteers, farm team members and contractors. We offer huge, heartfelt Thank You’s to all of our supporters!
Sarah's Harvest - Market Garden 