Visitors to Greater Growth's 12,000-square-foot aquaponics facility must first step onto a hydrogen peroxide mat to remove unwanted bacteria from the soles of their shoes and then pass through an air curtain that whisks away critters looking to feed on tender plants.
In this highly controlled environment, rows of lettuce, greens, bok choi and herbs are suspended in a 32-foot by 100-foot insulated concrete tank through which flows a steady supply of the water and nutrients the plants need for life. The nutrients come courtesy of bright blue tanks of tilapia fish at the other end of the greenhouse, part of a symbiotic horticultural process that is 100 percent organic, says owner Joel Townsend.
Townsend, in partnership with his wife, Linda, founded Greater Growth in 2009. The Lenoir City startup is currently selling produce at local farmers markets and will soon launch a sales effort targeting area grocers and restaurants. It will begin selling fish, likely through local fish markets, in August.
Greater Growth represents the commercialization of a relatively new field that combines traditional aquaculture with hydroponics — essentially growing plants in nutrient-supplemented water — to create a system in which the two sustainably support each other.
"I own the URL for 'eat, swim and poop,' " Townsend says as he describes the fish's role in the sophisticated cultivation system, which forgoes the use of pesticides, antibiotics and hormones.
To accomplish this, however, he must keep nutrient levels in perfect balance and maintain strict quality control to prevent pests and disease from quickly wiping out crops. The vegetation cleanses harmful byproducts from the water, which is recirculated to the fish tanks where the process begins all over.
"Because we have fish and plants together it keeps us entirely honest," Townsend says. "There's nothing harmful to humans that I could put in here and not kill my fish."
Plants flourish in these conditions, reaching maturity about 30 percent sooner than traditionally-raised crops, Townsend says. Harvest and packing are also simplified, reducing the amount of labor required.
He views the operation as a kind of prototype that could be replicated in large metropolitan areas where agricultural land is scarce — he's already talking about a second-generation facility, although plans for expansion are still taking shape.
"I'm a huge fan of traditional agriculture," he says. "I'm just saying this is an alternative."
The greenhouse also was designed with the environment in mind. It uses a 10-kilowatt array of solar panels and features a 6,000-gallon rainwater collection system. The filtration system takes advantage of gravity, using pumps only to bring rainwater into the facility and to pump from the sump into the fish tanks.
Energy efficiency comes courtesy of the structural insulated panels that form the office building, triple-pane polycarbonate covering the greenhouse and an energy-saving heating system. An automated energy curtain keeps the greenhouse cooler when summer temps rise. A system of sensors monitors each function of the facility and, if something goes awry, Townsend receives a warning message on his smartphone.
The enterprise was not cheap, with construction costs of about $1.5 million, he says. It took him some time to land financial backing — the project was finally financed by ORNL Federal Credit Union — and it took time to work through the kinks of designing and constructing the brand new concept. It also will take time to earn a return on his investment.
"This is a lot of work. There has been a learning curve to it," he says. "I didn't do this to make a bunch of money. I do believe second or third generation you can make a bunch of money."
The company is currently revving up a sales and marketing strategy for its produce, which Townsend had, in initial estimates, projected would make up about 90 percent of revenues. Greater Growth will target Knoxville-area grocery stores and restaurants and, depending on response, potentially expand its reach to Chattanooga. However, in keeping with the company's sustainability mantra, Townsend aims to retain as local a customer base as possible.
There has been more of an interest in the aquaculture business than Townsend originally anticipated, and he says he's now in discussions with local fish market owners — including Phil Dangel of the Shrimp Dock in Knoxville and Alcoa — interested in featuring the product.
One unexpected, albeit perhaps minor, revenue stream has stemmed from Greater Growth's status as one of the first commercial aquaponics operations in the country. As a result of an outpouring of attention, Townsend began organizing onsite seminars featuring experts. The fee per person is $500 to $600.
"I get at least two calls a day from people who want to do this, and they just wore me out," he says. Thanks to a little experimenting with Internet marketing, the seminars are proving popular. He has held two with particiants attending from as far away as New England and California and has two more scheduled for June.
Greater Growth will soon offer the benefits of its fishy fertilizer to home gardeners too, bottling the waste solids unusable for aquaponics as "Pescadoodo Fish Poo" for sale to farmers market customers.
The product slogan: "We don't put the 'P' in poo, but our fish do."