Plan for Our Passive Solar Greenhouse

Once we installed our homestead utilities infrastructure and pulled our travel trailer onto our land we embarked on our first major construction project. Instead of building our home first, we decided to erect a passive solar greenhouse to gain some hands-on experience with construction materials and to test passive heating and venting strategies. We also prioritized the construction of our indoor growing space because we are anxious to begin producing our own food - hopefully year round.

How Our Passive Solar Greenhouse Works

When designing the greenhouse we considered the suns placement throughout the year. In the depth of winter at our latitude and longitude the sun reaches a height that is only 30 degrees above the horizon, while summer solstice sees the sun 80 degrees above the horizon at midday. The diagram below illustrates the difference between sun's path from winter to summer solstice.

To capitalize on the sun's seasonal placement we included many passive solar features in the greenhouse plan. The roof over-hangs are designed to prevent the summer sun light from entering the greenhouse. This should help to keep the structure cool in the summer. In the winter, when the sun is lower in the sky, sun light will freely enter through the South-facing windows and will warm the space. During the summer reflectors will direct sunlight through south-facing windows providing light for growing.

Click here to view the PDF version of "How Our Passive Solar Greenhouse Works".

Concrete Pad for Thermal Mass

To help our greenhouse better preserve the daylight warmth through the night we chose to build with stick frame construction on a concrete pad. In the winter when sun light streams through the windows and strikes the floor, the heat will be absorbed by the concrete pad and stored in its thermal mass. Through the night the heat will slowly be released into the building, reducing the need for additional heating. A small wood-stove near the center of the greenhouse will provide extra heat when necessary.

Blown Cellulose Insulation

Insulation in a passive solar structure is critical. With maximum insulation the structure will hold onto more solar heat. We selected blown cellulose insulation for its superior insulating qualities, as well as its sound proof and fire proof ratings. Our greenhouse plan calls for the exterior walls and roof to be heavily insulated.

Passive Solar Greenhouse Features

The South side of the greenhouse will have 6 large windows (not coated for UV reduction) that will allow ample light for year round growing. Clerestory windows will let light into the North rooms of the greenhouse which will be used for potting, starting seedlings and drying herbs. We also have plans to install a kitchen in the greenhouse for canning , butchering and processing harvested vegetables. On the North side a porch will be constructed to provide shelter for an outdoor container garden.

To view a PDF version of our passive solar greenhouse plans click here.

More About Passive Solar Greenhouses

Click here to read how we modified an existing greenhouse to give it passive solar characteristics.

Passive Solar House Plans

Click here to learn more about our plans for our passive solar home.

Click here for more about our off grid homestead plans.