Micro Climates
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I live at Cowley Lake, approximately 30 KM from Whitehorse. I recorded hourly temperatures for a period of two years and compared these temperatures with those at the Whitehorse airport weather station. The growing season at my place can be 20 days shorter than Whitehorse and temperatures can vary as much as 15 degrees C. You need to know the conditions of your own site and how these may differ from local weather stations. I have used a data logger to record these temperatures and this give a general indication of what to expect from weather forecasts and how I need to take precautions that will help minimize frost damage.
If you live on a larger property, you may want to try an experiment my neighbour conducted. She planted potatoes all around her property and recorded when and where each plant was struck by frost. There was as much as a three week difference even though the plants were all on her 5 acres. |
Specific site location
The ideal location in northern latitudes is one that provides a full sweep of the sun's rays, good frost drainage, and is preferably close to a large body of water that has a temperature moderating effect. Depending on the design, the orientation of the greenhouse should allow for early morning warming, some mid day shading and late afternoon sun. The pictures to the left shows two different designs and the appropriate orientation for each design. There are benefits and costs to each design in terms of solar gain and heat loss.
The arrows in the diagrams point north.
The arrows in the diagrams point north.
Optimizing the orientation and design
This picture shows a design that blends features of the two shown above. The solar gain from the morning and evening sun is captured, the mid-day sun is reflected to a greater extent and the heat loss is minimized by the insulated northern faces
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