Aquaponics carving out ag niche in LaPorte

By JoAn Bjarko
North Forty News

LaPorte has a new look in agriculture, with a key component buried underground and construction underway for an aboveground ecosystem that supports fish and plants.

Matthew Westenhaver, who is experienced in raising hydroponic vegetables, is taking that concept a step further with aquaponics, an integrated system where plants and fish grow together. The concept is relatively new, but successful systems are operating from Alberta, Canada, to Africa.

Aquaponics combines aquaculture and hydroponics. Fish waste provides a food source for the growing plants, and the plants provide a natural filter for the water. Working together, they cut water use and avoid wastewater disposal problems.

Before breaking ground on his own aquaponics system at 3430 W. County Road 54G, Westenhaver took a summer training course at the University of the Virgin Islands. There a commercial-scale operation has a multi-year track record, but the growers don't have to worry about freezing temperatures.

To accommodate Colorado's climate, Westenhaver is building a 36-by-130-foot greenhouse with an attached 30-by-80-foot steel structure fish house. He will reduce energy costs with a subterranean heating system consisting of three layers of corrugated flexible tubing covered with 800 tons of 1.5-inch crushed rock.

The tubes come to the surface where they connect to intake fans and exhaust vents. During the day, a fan will move moist, solar-heated greenhouse air underground. The air cools as it passes through the tubing system and then returns above ground. At night, the circulating air draws heat from the rocks and returns to the greenhouse as warm air. Plans also call for incorporating solar- and wind-generated electric power, as well as solar-heated water.

"It will cost more to get started, but save money in the long run," Westenhaver said.

He and his parents, Ken and Marcia, have already tested a subterranean heating system by installing a much smaller version under a sunroom added to the 1923 farmhouse on the LaPorte property. The sunroom sports large windows purchased from ReSource on North College Avenue. The Westenhavers also experimented with recycled concrete to cover the subterranean tubing, but concluded the material is too porous to hold sufficient heat. With that in mind, they chose rock for the greenhouse system.

Westenhaver located the sunroom on the south side of the house, where it replaced a dilapidated porch. When December temperatures dipped below zero, the sunroom stayed above freezing and the houseplants survived. For close calls on the thermometer, however, a small propane heater can give the room an extra measure of warmth.

When the system is operational, Westenhaver plans to raise tilapia, which could be sold to restaurants or fish markets. The business will have four 1,000-gallon fish tanks filled with tilapia of different ages. It takes 10 months to grow market-sized fish.

"There will be a lot of water testing," Westenhaver acknowledged.

Basil and lettuce will grow in the greenhouse until Westenhaver is ready to diversify. Produce could be sold to restaurants, at farmers' markets or through community-supported agricultural organizations.

Once the system is working smoothly, it could be expanded to raise trout as well as other herbs and flowers. With a year-round controlled greenhouse environment, the business could also grow herbs on contract for timely local delivery.

Westenhaver has a strong interest in a self-sustainable lifestyle, so aquaculture fit right in when he decided to start a business. His goal is to be in operation by spring, weather permitting.