The Economics of Aquaponic Farming, According to EFC Germany

EFC Farmsystems’ Marie Schönau was packing up a freezing cargo van at 5 AM in Berlin when I called her from the much warmer confines of a rental house in Los Angeles this past January. At the time that we spoke, Schönau was making a delivery and had graciously agreed to conduct an interview en route, pressed as she was for time. 

EFC Aquaponics, a subsidiary of EFC Farmsystems Berlin, is a commercial-scale aquaponic vegetable operation based in Germany’s capital city. Fish feed on the roots of vegetables growing in the company’s water beds, while the plants benefit from the nutrients (in the form of fish manure) that the organisms release into the water. The fish, which are literally grass fed, are then sold at markets alongside the vegetables they indirectly help produce– a perfect closed-loop food system. Below, Garden Collage speaks with Schönau about her involvement in the operation and what it could mean for the future of sustainable agriculture, both in Germany and beyond.

GC: Where did the idea for a large-scale aquaponic farm come from, and how did you get involved with EFC?

MS: EFC’s two founders, Nicholas Leschke and Christian Echternacht, were both very much into healthy food and sustainable food production, and when they first came up with the idea, it was more like a hobby. You know those huge shipping containers? Well, the first model of the aquaponic farm was actually in a shipping container; they build the fish tanks inside the container and put the greenhouse on top of it.

They did some crowdfunding with their friends and family to cover the cost, and they rewarded them with a big perch barbecue where everybody could eat their own fish. The media was so interested in the concept that they came for interviews all the time, and as a result of the coverage, interested consumers started coming over and asking for products. Because the demand was so high, they had to make the farm work on a bigger scale so that they could sell. That’s how they invented this kind of aquaponics system.

As far as we know, there is no other system that can work on this large of a scale, because usually when you have an aquaponics system, it’s a completely closed circle, and it’s very difficult to work with the specific vegetables most people want without adding artificial nutrients. In our system, we rear the fish without any antibiotics or other medicine, so we can really have a closed-loop system because of the technology EFC invented.

GC: So what do you grow now? And can the fish only eat certain plants? What does their diet include?

MS: Last season, we had a warm house and a cold house. In the warm house we had tomatoes, cucumbers, paprika, eggplant, and lemongrass. In the cold house, we had different herbs like oregano and thyme. We also had bok choy, mangoes, and different varieties of kale– including a special variety called black kale. 

GC: Where do you sell the produce?

MS: There are so many things still changing, because we’re just starting off, so what we’re going to plant next year will probably not be the same as what we planted last year. How we’re going to sell the products is also going to change, because we actually first started with a direct-selling subscription model– we had a weekly vegetable box that our customers could pick up directly at the farm, which consisted of whatever vegetables we could harvest at the moment.

“As far as we know, there is no other system that can work on this large of a scale, because it’s a completely closed circle, and it’s very difficult to work with the specific vegetables most people want without adding artificial nutrients…”

There were always some tomatoes, cucumbers, salad greens, and always some kind of herb. But after a while, we thought that this model is a little bit difficult, because our set up is big, but it’s not so big as to always have the variety to fulfill the people’s needs for the whole week, and our subscription model we had only had the capacity for 200 people. After two weeks we were sold out, and we had a waiting list of another 200 people. That was amazing. But at the same time, our 200 customers were not always completely satisfied because they wanted more of some products more and fewer of others, so we decided it’s better to open up publicly so that our customers can just come over buy what they need. So, we’re now opening our own booth at a local market. We’ll be selling our products in the middle of Berlin three days a week.

GC: What is the yield of vegetables? Do you have numbers on how many pounds of produce you put out each growing season?

MS: We will produce 35 tons of vegetables a season, but the weight is not what is the most important. For example, we’re going to change our production to include a little more of some kind of sprout– microgreens have basically no weight, but they are a nutrient-dense product.

GC: How many people work on this aquaponic farm? Do you have volunteers?

MS: Yeah, we have volunteers. In summer we need more volunteers than in winter. We have the two founders and myself in the office, and we have five people working in the farm, and then about three regular volunteers.

GC: I have a question about the fish: do you use just one type of fish, or are there multiple types of fish in the tanks?

MS: It’s one type of fish, and also it’s important that we work with just one kind of fish in a closed system. If all the agriculture is a closed system– then it can only work with one kind of fish, otherwise the risk of diseases is very high. We work exclusively with perch. We call it pink perch, because the fish is actually a little bit pink.

GC: Do they require any other special treatment? You said you don’t need to feed them outside of the closed system, but do they require anything else to survive? Or do you just leave them alone?

MS: The only input the fishes get in our system is rainwater and three or four percent fresh water.  And of course, their feed which is 100% certified organic. That’s all. There’s nothing else, and we don’t work with any antibiotics. We always try to keep the fish as healthy as possible, which means that the density in the tanks is very low compared to other aquaculture systems.

GC: That’s amazing. What happens in the winter? What does the system look like right now?

MS: Usually have a warm house and a cold house in winter, but to maintain the high temperature requires lots of energy expenditure, so we decided to not do the warm house in winter. In the cold house we grow salad, kale, and herbs, which doesn’t really change much in winter other than the fact that we are aiming to install LED lights, which I think will make a big difference in the growth rate of the plants in the colder months. So the cold house looks the same, and the warm house is empty until May when we can start harvesting again. That’s the best part.

To find out more about EFC Aquaponics or to schedule a visit to their public aquaponic farm, visit the company’s website.