It’s almost time for dinner on a Saturday in December. The snow is falling in slushy lumps outside, the roads are terrible, and you definitely don’t want to go out for food. However, you decide to bake some crispy fish fillets with freshly harvested produce. Rather than go out to the grocery store, you head into your basement, to your private garden; it’s bright, warm and relaxing inside the mylar enclosure. After enjoying a couple deep breaths of oxygen rich air, you harvest some lettuce and kale, a few strawberries, the herbs to season the fillets with, and net a couple bluegill from your aquarium, then head back upstairs to preheat the oven.
Fresh fish in January may sound like a dream, but many people are already operating this type of growing system in their homes and greenhouses. It’s called aquaponics.
While aquaponics existed for more than a century, it’s been enjoying a burst in popularity lately as one of the healthier and most sustainable ways to produce food.
“It’s beyond organic,” said Avery Ellis, designer and consultant for aquaponics supplier The Aquaponics Source, “[the plants and fish] have to really work together in a symbiotic way.”
This is because an aquaponic system uses the waste from fish to feed the plants.
According to Sylvia Bernstein in her book “Aquaponic Gardening”, fish waste is processed into nitrates for plants by bacteria within the system. The same water is cycled back and forth from aquarium to growbed repeatedly, so nothing can be added unless it’s healthy for plants, bacteria and fish. This ensures the entire system is organic and the produce is healthy for consumption. Even hazards from city water like added chlorine, or waste plastics building up in oceans, are absent from aquaponic systems.
The system is a pure microcosm of nature.
“In nature, you never see plants without animals,” said Youssef Darwich, farm manager at Grand Valley State University’s Sustainable Agriculture Project.
Darwich has been developing an aquaponics system in his basement for growing leafy greens like lettuce. He began his system with a kind of fish familiar to most people.
“Goldfish are just easy,” he explained. “They’re hardy and they’re pretty cheap.”
How expensive the fish are is important when first starting up. Bernstein and Darwich agree that a young system is likely to end up with a few dead fish in it.
Darwich is optimistic about producing edible fish as his system grows, though.
“Fish are much more efficient at turning their food into protein because they don’t have to develop rigid bones to support themselves,” he said.
According to Bernstein, cattle raised for beef burn a significant amount of energy fighting gravity to stand up and walk around. Fish, however, use most of their food energy to grow as they float effortlessly in water.
In a year, aquaponics can generate up to 35,000 pounds of edible fish and thousands more pounds of vegetables per acre, but grass fed cows can generate only about 75 pounds of beef per acre, Bernstein adds.
And because of the closed-loop technique, aquaponics isn’t limited to lush valleys or rainy coasts, it can be utilized almost anywhere.
“It’s a way that you can actually conserve a lot of water,” Darwich said.
According to Bernstein, aquaponics wastes no water. The only water lost evaporates from the aquarium or is absorbed by the plants. She asserts that growing aquaponically uses less than a tenth of the water compared to soil-based gardens. This makes growing food in this style an excellent option for growing in urban “food deserts”, where no fresh food is grown or available, and actual desert areas like Arizona and Nevada.
Ellis also highlighted the drought and irrigation issues in California and contends that aquaponics could grow the same produce, but organically and without draining water reservoirs.
“These [aquaponic] systems are a sustainable alternative,” he said.
However, aquaponics still faces some economic challenges.
“We need market forces to adopt these techniques,” Ellis said pointing out that current federal and state farm subsidies only support large-scale industrial farms, leaving sustainable growers to fend for themselves while competing against Californian produce farms.
According to Carole Engle of the Aquaculture and Fisheries Center at the University of Arkansas, as of July 2015, aquaponic growing styles would be difficult to make profitable. This is partially because the plant produce has to compete with industrially farmed produce, and also because the fish densities required in aquaponics tanks are much lower than what can be achieved with pure aquaculture techniques.
This reduces profitability in any market that isn’t concerned about sustainability or whether their produce is organic.
That hasn’t stopped The Aquaponics Source, based in Boulder, Colorado, from pushing forward with home and production-scale systems that they market online and ship worldwide. They also supply and consult larger farms looking for further expertise.
“As you get larger, these systems become more efficient,” Ellis said.
Once an aquaponic system is established, it becomes easier to expand it than build a new system, and larger systems can still use smaller pumps.
According to Bernstein, larger systems are also more stable, so they’re easier to maintain. This gives her hope that aquaponics might eventually replace industrial fishing and aquaculture, both of which cause significant environmental damage.
Aquaponics isn’t going to replace cattle farming overnight, but perhaps the occasional aquaponically grown fish will land on your dinner plate soon.