September 5, 2017 at 3:32 p.m.
Since 2010, the Vriezes' farm expanded beyond cows when they built a 27,000 square foot greenhouse across the road from one of their two farms, Baldwin Dairy, where they milk 1,000 cows in St. Croix County near Baldwin, Wis. The manure from the anerobic digestor provides the energy for the greenhouse. Inside the greenhouse - called Future Farm, Food and Fuel - the Vriezes use a hydroponic and aquaponic system that grows butterhead lettuce, frilly lettuce, greenleaf, cress, basil and chives, along with raising tilapia and catfish. Hydroponics is growing plants in nutrient-enhanced water without the use of soil, and aquaponics is raising fish, then recycling their water to grow plants in a hydroponic system.
"It was different for us. It's been a big learning curve," John said about taking on a venture outside of dairying.
The idea for the greenhouse came about when the biogas from their anaerobic digester was no longer economical to sell. They thought about the next best use for the energy and came up with the idea of making heat to warm a greenhouse.
"It's a way to sell a value-added product versus wholesale energy," John said.
These value-added products - vegetables and fish - weren't the only attraction for putting up a greenhouse. The Vriezes said using the hydroponic and aquaponic system is sustainable by reducing water use and create a smaller carbon footprint.
"We have customers who appreciate those sustainability efforts," John said.
John said it takes 30 gallons of water to grow one head of lettuce that is grown in soil. Using the hydroponic system, it only takes about two to three gallons.
"It's substantially less water because it's an enclosed area and water is recirculated. No waste leaves here. One project feeds the other project," John said.
The Vriezes receive the tilapia and catfish as fingerlings from growers in the southern part of the United States. All fish come with health certificates to ensure their quality. The fish are first put into a smaller-tank nursery area before being transferred to the six larger 1,200-gallon tanks. With three tanks holding tilapia and the other three with catfish, the Vriezes have a total of about 4,500 fish.
"It's different going from cows to fish," Pam said. "The one nice thing is that even when it's 30 below outside, we're still working, but not out in the elements."
Water, which stays at a consistent temperature of about 72 degrees, is run through a filter and through a UV light before it is sent out to the plants. After the plants take the water they need, the water is brought back to the fish and through the filters.
"The fish feed the vegetables so we don't have to use much fertilizer," John said.
At this time, the water from the fish provides natural nutrients for the plants in the aquaponic system. Some nutrients are added to the water.
"It's always a clean, recirculation system," Pam said. "And the fish are dual purpose."
It takes about six to seven months for the fish to grow to the perfect fillet size of about 1.5 pounds.
The plants take about one month - although in the summer it is shorter and in the winter it takes longer - until they are ready to harvest. The Vriezes use two types of systems to grow their plants - trays and rafts. Since starting the venture, they've realized they prefer the rafts.
"The rafts are more efficient and not as labor intensive as the trays," Pam said.
Growing the plants first starts with the seeding process. About four days a week, the Vriezes, along with help from seven employees, put seeds in small holes of growing medium. Once the seeds have grown enough to have roots, they are transferred into the raft system. Each raft is a large Styrofoam board with a small hole for the plant. The Styrofoam floats in water, leaving enough room for the roots to be submerged. For the tray system, seeds are put directly into trays and water trickles underneath through little tubes.
"That requires a lot more maintenance than the Styrofoam rafts that just float in the water," Pam said.
She also said the bays are easier for harvesting.
"When we harvest, it smells so good in here. We can really tell what we're harvesting," Pam said.
After harvesting, the Vriezes package all their plants and deliver them to the customers the same day to keep the products fresh. The Vriezes also fillet and deliver all their fish.
Monitors in the greenhouse hang from the ceiling and report back to the main computer to regulate temperature. In the hot summers, the computer will close the top shade to shield the sun, and also turn on circular fans and the water wall to cool the room. During the winter, the shade also closes and the heater turns on. The greenhouse is surrounded by an extra wall, which prevents bugs from being pulled in by the fans.
Before the greenhouse was built, the Vriezes practiced raising fish on a smaller scale and used the Internet to educate themselves about growing vegetables in a hydroponic system.
Once the greenhouse was completed in 2010, the Vriezes had to take their own crash course in using a hydroponic and aquaponic system.
"We had to learn a lot from trial and error," John said.
The Vriezes said the industry is not as open as dairy about sharing management tips.
"In this business it's harder to share information because there aren't as many people into hydroponics and aquaponics," Pam said.
Another challenge was that they had to create their own marketplace, merchandising and provide their own trucking.
"Unlike selling wholesale, you have to gain the trust of the people buying from you and you have to educate them," John said.
They have 18 customers ranging from restaurants and grocery stores to senior living homes and corporate headquarters in downtown Minneapolis. About 95 percent of their business comes from the Twin Cities metro area.
"We had no choice but to get into the marketing. We would have rather been just farmers," John said.
Pam handles most of the marketing, which she really enjoys.
Despite the large learning curve, the Vriezes have enjoyed their new venture. John said he likes building the business while Pam enjoys working with the customers and watching everything grow.
The Vriezes are excited for the greenhouse and the growth possibilities in the future.
"Our farm has always been evolving and changing," John said.
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