SHEBOYGAN COUNTY — At Lake Orchard Farm Aquaponics, Nate and Mary Calkins have created their own little ecosystems using about 1,300 fish to create as much as 55,000 heads of lettuce for the Sheboygan region.
"A system like this could technically be found on a space station given the right equipment," Nate Calkins joked. "We don't buy any additives, there's nobody that ever stops by to give us any chemicals or enhancements for our water or anything. This is a truly closed system in that regard."
With the 4,000 square foot greenhouse, Lake Orchard is about to produce about the equivalent of six acres of ground.
What is aquaponics?
This unique form of agriculture at Lake Orchard creates its own little symbiotic ecosystem using fish, water and natural bacteria and nutrients all to grow plants in a soil-less medium.
"Literally speaking, aquaponics is putting fish to work," states The Aquaponic Source. "It just so happens that the work those fish do (eating and producing waste), is the perfect fertilizer for growing plants."
"Instead of enhancing the water with mined fertilizers, we use fish manure as a nutrient management program," explained Calkins. "Often, straight out the gate people will go, 'So do you spread the manure right on the plants?' and that's not it at all. What it boils down to is we raise the fish in separate tanks, mainly because the fish would definitely cause damage to the plants."
On one side of the Lake Orchard Farm facility, you'll find two separate ecosystems—one for fish under three months of age and the other with full-sized fish—where the fish are creating the nutrient-rich water that will then be pumped over to the greenhouse to grow the plants in. For Lake Orchard, that means a variety of different kinds of lettuce, which is then distributed to area restaurants and sold by wholesale and retail.
Because of their rapid growth, which means more food and more waste, Lake Orchard uses fresh-water tilapia to run its system.
The waste produces ammonia and nitrate compounds. Because plants need more than nitrates to survive, the tilapia are fed pellets that are about 90% of fish renderings from processors including Schwarz Fish Company in Sheboygan. This way, no other additives are needed.
"They end up with the heads, fins, gills, bones, eyeballs, all that stuff leftover when you take the meat off. All that stuff contains a lot of those natural elements that we need to produce our plants," Calkins said. "They grind those renderings up then dry it down to a pelleted form."
The nitrate- and ammonia-rich wastewater can be toxic to plants, however, so Lake Orchard then passes it into a clarifier, which is similar to a settling tank in a septic system.
"It’s like if a dog goes to the bathroom in the yard and you get that brown spot," Calkins explained of the wastewater. "That’s because it’s really intensely high in nitrites and ammonia compounds and it burns out the plants. But if you look, the grass is higher in a sort of donut ring around the brown spot. The reason is, by that spot where the intensity level is down, the natural bacteria in the soil processed those nutrients and made it into nitrates and then the grass grew higher. We use that living bacteria as our processing center for the nutrients."
Once again, no additional bacteria needs to be added.
Because of the toxicity, the wastewater is then run through a "Zero Discharge Extra Production" System, where it is filtered and then stored in the greenhouse sump tank. That water is then pumped out twice a day to flood the flower beds with the nutrient-rich water to thrive. In the greenhouse, the plants are placed into a half-inch foam top layer so they can float in the water basins.
As Calkins said, it all comes back to the fish.
“One of the biggest things that we try and do is create a very, very steady and stable environment for the fish," he said. "Fish are really susceptible to stress, and if they’re stressed by anything, they don’t eat, and if they don’t eat, they don’t poop. If they don’t poop, we don’t get nutrients, and then we don’t get lettuce. So really, it’s all about just making our fish happy.”
From start to finish, the entire process from pellet to plant can take about six months.
What are the benefits?
In addition to developing a more sustainable way of farming, aquaponic farms also offer unique benefits including consistency and year-round growth.
"In any kind of Earth growing, you can get a big differentiation in the soil content," Calkins said. "If it's a higher clay content, there could be water that can run through cracks in the clay, not getting to the roots, things like that. Different soils have different things in them, so here we do our best to maintain a very steady, stable pH and water temperature."
The system also doesn't use nearly as much water as you'd think. Calkins said they average about 200 to 300 gallons of water usage a day compared to the average household that uses about 400 gallons.
When removing the Wisconsin weather element, this also means their farming can also be done year-round.
"This is allowing year-round farming and also saving a lot in shipping, tracking and also creating a lot of awareness as to where your food is coming from," Calkins added.
One aspect of their mission being raising awareness for locally sourced food, Lake Orchard frequently offers tours of its aquaponic farm. But that can also leave some hesitancy in consumers about their product after watching fish swim around in their own poop.
“It took a while for people to wrap their heads around an operation like this," he explained. "We’ve had plenty of people say it’s strange or, ‘Oh, I’m not going to eat that,’. Transparency is key, in my opinion, from a farming operation. Not everybody is going to get to go on a tour of their milk producer’s dairy barn, but it’s getting more and more important to people to know where their food comes from.
"Between transparency and offering people the opportunity to just pop in and check things out, it’s offered a lot of reassurance not only from a cleanliness standpoint, but they also felt warm and fuzzy learning about and eating this food by seeing how it’s actually grown and produced," he added.