A new way to grow edible crops has been discovered, resulting in crops that mature twice as fast and use less than one-tenth of the water compared to traditional methods. This technique is scalable and can be used for home herb gardens or large-scale commercial production. In a state facing prolonged drought, the concept of gardening and farming with significantly less water is highly appealing. However, there is one catch – it involves the use of fish.
Aquaponics, a novel growing method, combines aquaculture (the cultivation of fish for food) with hydroponics (growing plants without soil). This combination is beneficial because aquaculture produces fish waste while hydroponics requires fertilizers. When combined, the plants act as biofilters for the fish, using their waste as fertilizer. As a result, aquaponic growers can sustainably cultivate both produce and fish.
To begin with aquaponics, growers need to make the initial choice of a system. Several types are available and can be obtained commercially or made by hand. The options vary from an indoor system comprising an aquarium and a basic grow bed to outdoor systems that rely on solar power and are managed within greenhouses or hoop houses. In northern Nevada, the recommended choice for growers is indoor or greenhouse-based systems. These systems provide protection for fish during the region’s potentially harsh winter weather, which can vary depending on the year and the specific microclimate associated with the system’s location.
To grow aquaponically easily, separate containers can be used for fish and plants, which can be connected with plumbing to allow water to recirculate from the fish to the plants and back again. In this uncomplicated setup, plants are grown in a coarse soilless medium, such as gravel or expanded shale, and are periodically flooded with used water from the fish tank. Beneficial bacteria naturally accumulate in the system and convert fish waste in the water into plant food. Composting worms can be introduced to the growing medium in systems like this one, which involve periodic flooding and draining, to assist the bacteria in this process. Once the plants extract the nutrients derived from fish waste by natural bacteria and worms, the now re-oxygenated and clean water is recirculated back to the fish tank.
Full-Circle Food Chain Aquaponic Food Production
The funding for the Aquaponics Unit at the University Farm at Chico State came from a $15,000 Student Fee Grant. It was constructed in a refurbished hoop-style plastic greenhouse and was designed and built by mechanical engineering students as a senior project, similar to the Soldier Fly project. The unit consists of six arrays of pipes, each with the capacity to support the growth of 340 plants. When fully planted, one array is harvested and replanted every six weeks. To accommodate this, we have selected plants like lettuce, spinach, mustard, basil, and other species that can be harvested within a short six-week cycle. The aquaponics unit received organic production certification as of last summer.
The Aquaponics Unit and Soldier Fly research will eventually create a complete food chain on campus. The Soldier Fly larvae, which are currently fed organic fish food, will be provided with pre-consumer food waste from the cafeteria. The fish tanks outside the greenhouse and the plants inside the greenhouse are connected through circulating water. The water, which contains effluent from the fish, is pumped to a biofilter where bacteria convert ammonium nitrogen in the water to nitrate nitrogen, a more suitable nutrient for the plants. The plants extract the necessary nutrients from the water, improving its quality, and then the water is circulated back to the fish. Finally, the plants grown can be used to provide food for the cafeteria on campus.
The project offers plenty of chances to gather information on effective methods. It’s a complex procedure that necessitates keeping a careful equilibrium. When there are excessive fish in comparison to plants, the plants won’t be able to effectively extract the nutrients, potentially resulting in the death of the fish. Conversely, if there are not enough fish, the plants will lack necessary nutrients.
