Serving Boone, Blowing Rock, Banner Elk, and other towns of the North Carolina High Country
Founded 05-05-05

High Octane Solution

New Greenhouse Will Run on Nearly Everything

Story by Lois Carol Wheatley

The naysayers tell us we can’t make it on any alternative energy source alone, that solar, wind, methane or geothermal won’t supply the kind of volume needed to wean ourselves off of oil.

Fine. That may well be true. So let’s think about using all of the above.

Imagine, if you will, a passive solar greenhouse built on top of an old county landfill with supplemental wind turbines and a subterranean system of pipes that operate on geothermal principles.

The only thing missing from this picture is the used French fry grease.

Construction on such a project has begun in Laurel Bloomery, about five miles north of Mountain City on Highway 91 in Tennessee. Behind the effort are J. Jackson, a Johnson County horticulturist specializing in native ornamental plants, and Joe Savery, a marketing wizard. They expect to have the nonprofit greenhouse, a 24- by 96-foot structure enclosing approximately 2,500 square feet of green space, finished and open to the public by about mid-May—though having actual plants for sale will likely take a bit longer.

“And we’re looking at photovoltaics,” said Savery, “a two-and-a-half kilowatt setup that we’ll be putting up there as well.”

Progress to date has been made possible by a $40,000 grant from the Department of Agriculture’s SARE program (Sustainable Agriculture Research and Education) and funding from the Appalachian Regional Commission. It has also been empowered by technical assistance from Appalachian State University, East Tennessee State University and University of Tennessee.

The most groundbreaking aspect of the greenhouse design, if you’ll excuse the expression, is that maze of underground pipes.

“The foundation heating and cooling system is considered a hybrid between rock bed heat storage and earth tube technologies,” said Jackson. “Two 14-inch heating and air conditioning fans drive two ends of the system, through almost 3,100 linear feet of four-inch black corrugated plastic drain pipe.”

The pipe is laid in a bed of rocks and effects a total exchange of air volume five times each hour, with the air pulled underground and brought back up. Moving the air slowly under the ground creates a “phase change” as water is turned to vapor and back to water.

“The change from vapor to water gives off heat,” said Savery. “And so during the day in the winter we’ll be capturing that heat and then recirculating it back into the greenhouse at night. Basically it will run all the time, and it moderates the temperature, both on the hot side and the cold side. It will eliminate 80-plus percent of the cost of energy to run the greenhouse.”

Chuck Smith, director of the Office of Sustainable Development at ASU, is supplying various levels of assistance. “We’re serving as academic and research support for the greenhouse project at the old Johnson County landfill,” Smith said. “We help them both at the agricultural and technical level and hopefully in the future we’ll be providing them with students and researchers for the project.”

The landfill greenhouse will reap the benefits of Smith’s considerable years of experimentation. “We have a test facility located at Parkway School that we use for research and we have hoop houses, which are modified greenhouses, where we operate a sustainable development teaching and research farm in Valle Crucis,” he said.

The University of Tennessee is posting a website for Appalachian Native Plants, Inc. at anpinc.org. The Tennessee Valley Authority donated the wind turbine. A private citizen in Shady Valley donated the greenhouse structure, a standard, off-the-shelf model.

“All we have to do is get our grid put in underground and put the greenhouse on top of it,” said Savery.

The project’s major emphasis is on improving the local economy and providing educational opportunities for former tobacco farmers. It is also focused on helping them market their wares.

“Our great hope is to develop a plan that will economically move this out into the community where people can grow a little cash crop,” said Savery, “whether it be fruits and vegetables, or like we’re starting off with native azaleas. The big thing we have found is that a lot of facilities lack a marketing plan—where am I going to sell it if I grow it and what shall I grow to sell? So that is part of our game plan.”

Jackson and his wife run a small wholesale nursery near Trade known as Tennessee Rose. For the past 20 or so years, they have headed up into the mountains in the springtime when the native azaleas and rhododendron are in bloom and, using a hand-held GPS, mapped the locations of prime specimens. They return in the fall to gather ripened seeds that they cultivate in huge trays. With minor modifications, the cold frames used to start tobacco seedlings could be adapted to this use.

In June, Jackson plans to give demonstrations at the new landfill greenhouse on growing native azaleas and rhododendron from seed. Later in the season, he’ll offer some sessions on “organic vegetable production and probably fruit crops, blueberries in particular.”

Long range, he envisions substantially expanding operations at the old county landfill—adding a classroom building, an office, a teaching greenhouse, display gardens and trial gardens.

“It will always be county land,” he said, “and it will always belong to the citizens of the county.”