Farm to School greenhouse taking shape
Construction on the Farm to School greenhouse in Fairfield is well underway.
The outline of the 96-foot-by-34-foot greenhouse is visible and enclosed in plastic. The future garden is nestled behind Schaus-Vorhies Manufacturing near the intersection of Stone Avenue and Ninth Street.
Freezing temperatures have been an obstacle to construction, but volunteers have overcome them. In fact, 30 truckloads of organic soil were recently dumped on the property, which was enough for four feet of new dirt throughout the interior.
Perhaps the most significant development occurred when organizers were able to move a 17,000-gallon tank that will eventually lie underground and heat the greenhouse with excess heat from the neighboring Schaus-Vorhies building. Jan Swinton, local food coordinator at Hometown Harvest of Southeast Iowa and one of the chief architects of the greenhouse, said the tank had sat unused for years and was considered a nuisance.
The tank was county property and was used to store tar. Jefferson County Supervisor Dick Reed said it stored tar the county no longer uses because it has found an environmentally friendly alternative. He estimated the county hasn’t used the tank for 10 years.
Jefferson County engineer Scott Cline has tried to find a buyer for the tank but to no avail. Swinton was the only one who expressed an interest in it. Since the county couldn’t sell the tank it decided to donate it to the greenhouse project. Fortunately, the county only had to move the tank a few blocks.
Unfortunately, the tank is so massive it had to be put on a rig. Cline said it was the same rig that transported the tank to its original location in the mid-1970s.
The tank is now inside Schaus-Vorhies where the tar residue is being removed and insulation is being added before it goes in the ground. The tank will rest in a hole 12 feet deep and will be covered by 4 feet of soil.
Schaus-Vorhies produces plenty of excess heat at its facility. The air that normally escapes from the chimney is 180 degrees. The plan is to use that excess heat to warm water in the underground tank. Tubes from the tank will feed the hot water into the soil underneath the greenhouse, which will in turn heat the soil and the air above it.
Swinton had to find a tank that could hold a massive amount of heat. When Schaus-Vorhies is in operation and producing heat, the heat goes directly to the greenhouse. Swinton needed enough hot water to heat the greenhouse when the facility was not in operation such as over the weekend, and that is what why the 17,000-gallon tank is necessary.
Swinton said the hot water in the tank will heat the greenhouse just like a geothermal system heats a building.
“A geothermal system heats the concrete floor, which warms the whole building,” she said. “We’re heating the soil, which will heat the whole greenhouse.”
She expects the top foot of soil in the greenhouse to be 70 degrees once the hot water starts flowing in. Swinton hoped the project would be a little further along than it is at this time of year and that the hot water would be heating seeds in the ground. Unfortunately, the sudden freezing temperatures have made planting seeds difficult. Now that the greenhouse is sealed, she expects seeds will be planted before Christmas.
The seeds will be for salad greens destined for the Fairfield High School cafeteria. Swinton said the kind of cold season crops that would grow well in the greenhouse during the winter would be vegetables such as carrots, kohlrabi and leaf lettuce. She hopes to grow cherry tomatoes next winter.
“We need a little higher temperature and a little longer day,” she said.
Swinton said she would have to add about four hours of artificial light to get the tomatoes to ripen during the winter months.
Another piece of produce waiting in the wings is the day-neutral strawberry. A day-neutral strawberry produces flowers and fruit continuously while the weather is conducive to growing. Swinton plans to hang the strawberries from rafters in the greenhouse and water them through an irrigation drip line. Swinton said earlier this year she hopes to have 1,500 hanging plants in the greenhouse when it is fully operational.
Swinton received more good news this month when she learned the greenhouse project would receive a check for $8,500 from TransCanada Pipeline, a petroleum company that does work in Iowa. Other funding sources for the greenhouse have been a grant from the USDA for the Farm to School project and from Alliant Energy’s “Bright Ideas” program.