Citrus Grown in the Snow in Nebraska Using a Geothermal Greenhouse
“We can grow the best citrus in the world, right here on the high plains,” says Russ Finch, the former mailman who is the creative superstar genius responsible for building the Greenhouse in the Snow. And he can do it spending only $1 a day in energy costs.
Canopy of lemons, grapefruit-sized oranges, green figs, and bunches of grapes are held in a citrus grove with trees on the Nebraska plains. This is done indoors made possible due to the fact that the technology used taps into the core of the earth’s own energy, geothermal heating in the winter and cooling in the summer. This technology being used in the greenhouse has been made possible thanks to Russ Finch, a former mail carrier and farmer. He refers to this kind of greenhouse as the Greenhouse in the Snow. He first built the first original greenhouse in the snow more than 20 years ago and it’s connected to his home.
Orange trees are a rare sight in Nebraska and Finch admits that the reason behind growing citrus was a way of showing that his geothermal greenhouse could work. In his quest to establish this greenhouse, Finch planted in the greenhouse any type of plant that they saw and then study how this plant would grow. No intervention was made as the plant would be left on its own and there are those that died and others survived. With this approach, he was able to find that they could grow practically any tropical plant.
Geothermal Heat for Greenhouse
Soil and water below ground contains a vast reservoir of thermal energy. Geothermal heating systems recover this energy and convert it to heat that can be utilized in greenhouses and other buildings. Geothermal heat can be classified into three categories but the most ideal for greenhouse is the Low temperature (50°F).
The soil temperature at the surface varies considerably over the year and closely follows the air temperature. At the 10-12′ depth it is more uniform averaging about 50°F with a variation of about 6°F above and below this level. There is also a lag time of about 8 weeks between the maximum surface temperature and the maximum soil temperature at the 12′ level which is helpful in winter heating and summer cooling. For the greenhouse production of perennials, herbs, nursery stock and some vegetables that require a temperature from 32-45°F this low grade soil heated air or water can be used directly.
For heating the greenhouse to a higher temperature, a heat pump is necessary. These are available as air to air, air to water, water to water or water to air systems.
It doesn’t stay hot in the greenhouse all the time. But even in a cold Nebraska winter geothermal heat keeps the orange trees comfortable. The key thing they try doing in this greenhouse is to keep temperature above 28 degrees in the winter. “We have no backup system for heat. The only heat source is the earth’s heat at 52 degrees at 8-foot deep.” Finch Said
Perforated plastic tubes form a network underground outside the greenhouse in a trench 8-feet deep where the temperature remains a steady 52 degrees year-round. A fan moves air through the tubes and into the greenhouse when it gets too hot or cold.
There are no propane or electric heaters, just a small motor that runs the small fan. This makes this technology environmental friendly with minimal carbon emissions. That means the greenhouse uses very little energy, keeping costs down to about $1 a day, all but cutting out the fossil fuels needed to control the climate inside. A typical commercial greenhouse uses gas-burning heaters and big fans to keep things steamy which are pollution to the environment and contributes significant amount of carbon emissions that worsen the global warming.
Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities. In 2013, CO2 accounted for about 82% of all U.S. greenhouse gas emissions from human activities. Carbon dioxide is naturally present in the atmosphere as part of the Earth’s carbon cycle (the natural circulation of carbon among the atmosphere, oceans, soil, plants, and animals). Human activities are altering the carbon cycle—both by adding more CO2 to the atmosphere and by influencing the ability of natural sinks, like forests, to remove CO2 from the atmosphere. While CO2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution.
Hardly can any greenhouse run all year on the northern High Plains because of the weather. The cost of energy would be too high for this o happen. But by tapping into the earth heat Finch has been able to drastically reduce the cost. This would be ideal to those areas particularly in parts of the country with cold winters.
Finch main business is selling the design of the greenhouse but he also grows a few hundred pounds of fruit each year to sell at local farmers markets. A new greenhouse costs $22,000 to build. So far he says 17 of them have been built in 6 states, and one in Alberta, Canada. That includes one nearby at the Alliance, Nebraska, high school where students grow tomatoes, cucumbers and other vegetables to serve in school lunches.
Finch believes the idea of a geothermal greenhouse is more than a novelty. He points to the challenges in the traditional fruit industry with greening disease threatening groves in Florida and Texas and California farmers searching for new water supplies. Why not move a segment of the citrus industry to middle-America? he asks.
“Not only can we grow [the fruit] cheaper on cheaper land, we’ve got the water, abundant sunshine, and you don’t have the transportation cost,” Finch said. “We can grow the best citrus in the world right here on the High Plains.”
It’s hard to imagine the rows of greenhouses you would need to replace a Florida citrus grove. But a place to grow oranges in Nebraska with little more than the sun and the warmth of the earth is still something to see. The use of ground heat is becoming more popular for residential and commercial applications. Due to the high temperature needed for conventional greenhouse heating, a heat pump is needed. Today’s equipment is more reliable at a lower cost than a few years ago. Where low temperature heat is needed, such as maintaining an air temperature just above freezing, direct use of the heat is possible. As the cost of fossil fuels increases, the payback for alternative heating systems shortens.