This is the first piece in ‘A Food Education Alphabet’: an A to Z look at food and words to help spread the word about food issues like sustainability and healthy eating.
What is aquaponics?
Aquaponics combines ‘aquaculture’ (breeding aquatic creatures, mostly fish) with ‘hydroponics’ (growing plants without soil using a nutrient-rich solution).
Brought up in tanks, fish produce waste. The water containing this is fed past plants, which are grown in floating containers or gravel beds. They take up organic fertilizer compounds from the waste through their roots, cleaning the water in the process. This is then returned to the fish tanks.
Ammonia contained in the waste is converted to nitrates by worms and nitrifying microorganisms. Larger pieces can be removed using filters.
A simplified diagram of how aquaponics works. Feel free to use – please credit Feast and Phrase and provide a link to this piece. The featured image for this article is from Flickr user IMCBerea College and shows Finnley Hayes at work in the Aquaponics Facility.
What are the benefits of aquaponics?
Two products are gained from one efficient, self-cleaning system, with much higher yields.
Aquaponics calls for significantly less land – about a tenth of what would be needed for conventional agriculture. Aquaponics can therefore be easily adapted for urban locations.
Because aquaponics works in a cycle, it only requires around 5 to 10 percent of the water that would be used in soil-based farming. This makes it ideal for growing produce in areas with limited water, like deserts.
A triple-tiered aquaponics system with fish, watercress, and running water. From Flickr user Justin Leonard.
In hydroponics and aquaculture, water must be regularly replaced to avoid the respective build-up of fertilizers and fish waste. This is not the case with aquaponics: in addition to the water taken up by plants, small amounts are lost in transpiration.
Hydroponics uses artificial fertilizers, which can be costly. Those used in aquaponics are organic and produced in the same location.
The lack of soil means no weeds or soil-based insects. As the water is naturally filtered, fish are also provided with a healthier environment and are less prone to disease, reducing the need for antibiotics.
This photo nicely illustrates the different levels involved in aquaponics. From Flickr user charlie vinz.
What are the disadvantages of aquaponics?
People may be put off by the cost of setting up the system or by the thought of having to take care of the fish, though these are not difficult to arrange!
There will be electricity costs for the water pumps, and those living in colder areas will need to provide a greenhouse to ensure more stable growing climates – again, not particularly pressing issues.
Is aquaponics ethical?
This may be argued both ways. Those who avoid eating fish may well object to rearing them for food and using them to grow plants. Others may say that providing the fish with a clean, filtered system is perfectly ethical.
Another photo of an aquaponics system from Flickr user Justin Leonard.
How long has aquaponics been around?
While the discipline as we know it today began developing in the 1970s, early precursors to aquaponics include the chinampas or cultivation islands of the Aztecs, and Southeast Asian paddy fields.
What kind of aquatic life can you breed?
Varieties of fish which are bred in aquaponics include trout, tilapia, perch, and koi, to name a few. Shrimp and prawns can also be used, as can crayfish.