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Food production is a difficult area in which to remove dependency on the surrounding world. Many people have moved away from farming their own acreage and providing their own food to going grocery shopping once a week at local stores. The prices we pay for food reflect more than the cost of growing crops—these prices also reflect shipping and transportation costs as well as markups for store profit. As fuel and fertilizer prices have increased over the past few years, local food prices increased as well.
Certain staples such as flour and sugar are best purchased from a grocery store, but vegetables and fruits can be grown inexpensively in home gardens and greenhouses. While an outdoor garden is subject to the weather, a greenhouse will allow you to grow your own fresh produce year-round. Since fresh vegetable and fruit prices generally go up during the winter, this is an excellent way to both reduce your expenses and control your personal food supply.
Solar-powered greenhouses provide a superior option for anyone seeking to grow fresh vegetables year-round while pursuing an off-the-grid lifestyle. Greenhouse kits are readily available on the market, and free construction plans can be downloaded off the Internet. A quick online search for solar-powered greenhouses will yield construction plans and building kits for passive, active and photovoltaic solar configurations.
One such resource can be found at https://www.builditsolar.com/Projects/Sunspace/sunspaces.htm. This site has an extensive list of solar collector and greenhouse construction ideas. Several structures involve the use of hay bales for additional insulation against winter temperatures. Note: Carefully read reviews of any greenhouse kit before choosing to build it, and do not work with a greenhouse plan that has received poor reviews.
Greenhouses can be attached to your home as a conservatory space, or they can be standalone structures. If you attach the greenhouse to your home, your current alternative energy and heating sources may be sufficient for growing plants year-round, and the greenhouse itself will provide additional warmth for your house during the day via passive solar heating. This type of construction allows for immediate access to your food regardless of weather conditions.
If you prefer to erect a standalone structure, select a site that receives strong sunlight for at least six hours per day. The next step is to determine which form of greenhouse will best suit your climate. In southern regions, a passive solar design may provide sufficient winter warmth to grow plants year-round without requiring actual electrical power to do so. If you live in a northern region where the temperatures drop below freezing on a regular basis, your plants will need additional warmth to survive.
Passive solar designs are constructed to make the most efficient use of sunlight without requiring electricity or wiring. These designs help concentrate the sun’s heat and warmth, allowing for extended or year-round growing seasons in milder climates. Active solar designs collect heat using a storage medium, and the heat is then distributed throughout the greenhouse using pumps or fans. Preferred storage mediums are air and liquids such as water, as these can retain heat and be easily pumped or moved between the heat storage area and the main section of the greenhouse. The power required for this type of greenhouse is minimal and can be provided by your existing alternative energy sources.
Photovoltaic solar greenhouses have solar panels and are self-sufficient with regard to power requirements. However, traditional solar panels do not permit much sunlight to pass through their surfaces, so care must be taken to position panels where they will not interfere with sunlight for the crops. Another self-sufficient option is the revolutionary method of treating windows with a photovoltaic glaze. This allows sunlight to pass through and reach your plants while still creating electrical power for heat and light. The photovoltaic glaze is a recent development in solar technology and is not yet in widespread use.
When reviewing greenhouse plans, pay careful attention to the greenhouse’s intended region. In climates with harsh winters, the greenhouse’s roof needs a steep pitch. In milder areas, the slant doesn’t need to be as steep. A steeper pitch allows the roof to easily shed snow and concentrate as much light as possible during the shorter daylight hours. In regions that do not receive snow, a hoop house with an arched roof will perform well. In general, a pitched roof means the design is intended to concentrate light, and this is not necessary in southern regions that receive a great deal of sunlight.
The glazing on the windows plays a large role in your greenhouse’s efficiency. You can choose whether to use plastic or glass windows for your greenhouse, and the glazing must be appropriate for that surface for best results. Plastic windows are lighter and less expensive than glass, and are suitable for most regions as long as they have the right glazing. A proper glaze will help concentrate the maximum amount of heat and light possible based on your climate.
Final considerations for your greenhouse are insulation, appropriate ventilation and irrigation. If you live in a region with harsh winters, you may need a thermal blanket to cover your greenhouse if the temperature drops too far below freezing. You may also need appropriate insulation underneath the greenhouse to keep your plant’s roots from freezing. Ventilation is a requirement for any greenhouse, as the plants will overheat and shrivel up during the summer if hot air is not allowed to escape. Finally, will your greenhouse be small enough that a bucket or garden hose is adequate for watering, or will you install a large greenhouse where sprinklers may be the most efficient method of distributing water to your crop? If you opt for a large greenhouse, photovoltaic solar panels or a wind turbine can provide the power needed to run your irrigation system.
