The system uses the constant ground temperature 2.5 meters (8 feet) below ground to heat a greenhouse. The underground-temperature on his farm is 11 degrees (52 degrees Fahrenheit). Other nearby areas range from 9 to 17 degrees (17 is near a hot spring).
Just circulating air through 64 meters (210 feet) of tubing buried 2.5 meters underground is enough to allow citrus and other plants to thrive. Selling at local farmer’s markets brings in a very high profit for farmers that can grow and sell locally.
Using the power of the sun to grow and the constant ground temperature to keep the air warm enough creates an opportunity to grow all year round. The same principles can be used to cool down indoor temperatures in very hot locations near the equator.
Due to the controlled environment growing organically is easy so that further increases the payoff for this type of farming.
The cost of the system can be as low as $25,000 if you have access to a backhoe to dig the trenches for the air pipes and can do much of the labor yourself. That is the cost of just the heating systems for a conventional greenhouse.
I really like this type of intersection of engineering and business (as well as environment and health benefits – providing healthy local food) that creates value to society by using our knowledge effectively.
Learn more at Citrus in the Snow. The Nebraska farmer (seen in the video) has been growing Citrus in Nebraska this way since 1992.
Related: Sustainable Ocean Farming – Beehive Fence Protects Farms from Elephants – For Many Crops Ants Can Provide Pest Protection Superior or Equal to Chemicals at a Much Lower Cost – Small Farm Robots