Aquaponics: A Sustainable Food Production Method
Aquaponics is a sustainable food production method that combines aquaculture and hydroponics. In an aquaponics system, we use the water reservoir as a fish tank to house fish we want to grow to farm and eat.
The fish are fed pelletized feed, and they produce ammonia and urea which is high in nitrogen. This ammonia is recycled to be used by the plants as fertilizer; the only input to the system is solar energy (or grow lights), fish feed and ph balancers, and the outputs are herbs, fruits, vegetables, and fish. Using solar or renewable energy sources to power pumps or heaters in cold climates makes aquaponics a highly sustainable way to feed a family household.
Aquaponics usually forms one of the aspects of sustainable gardening in a permaculture design system
But What About The Fish Waste?
Fish wastes in the form as both exhaled ammonia, urea and extreta is converted by bacteria in the system into nitrites and then nitrates, which are then used as nutrients by the plants. This is a very high nitrogen fertiliser and is great for growing leafy vegetables such as lettuce, spinach and herbs.
Aquaponics systems use a filtration media bed which is often scourier or clay pebbles which houses the bacteria. As the water moves past these filtration beds, the bacteria fix the fish waste into compounds the plants can use.
Solid fish waste is removed through the use of a settling tank, which can be used as a powerful soil conditioner and fertiliser, or just added to your compost patch to supercharge your compost!
How Big Of A Tank Do I Need?
There are many factors in choosing your aquaponics system.
An aquaponics system can be designed to suit your needs; aquaponics systems can range from a small aquaculture tank with herbs growing on the surface in floating media beds, to systems of huge fish ponds containing thousands of fish with water-irrigated rows of vegetables suspended above them. Larger systems typically use custom set ups with extensive piping and pump networks as the fish tanks, filtration media tanks and plant grow beds all have specific requirements on scale.
A more common backyard technique is to use second hand IBU’s made of food grade plastic. They are reinforced with welded steel cages, and can be easily moved when empty, and usually even have taps with standard sizing included ready to go! Using PVC piping along with header and reservoirs made of food grade 44 gal plastic drums or similar is all you need to get started. Getting creative about recycling materials is a key part of a sustainable permaculture design
[a backyard aquaponics set up showing the plant grow media using cut outs in pvc piping. Storage reservoirs underneath in blue]
Powering An Aquaponics System
Aquaponics systems by design will need energy input for things like powering pumps and aerators, but good passive gravity style designs can minimise energy use using things like header tanks and strategically placing tanks at different heights using a system of gates.
Depending on your climate, you may need heating to ensure the water is kept at an optimum temperature for your fish. Thankfully plants are a lot less fussy!
Using solar panels or other renewable sources of power like wind turbines to heat an aquaponic greenhouse over winter, or power your pumps will make it even more sustainable and reduce your reliance on the power grid.
Use Of Pesticides And Fertilisers In Aquaponics
Growing food in aquaponics means there’s no need for pesticides or fertilizers that may harm the environment; you only use organic methods and natural pest controls such as ladybugs, or exclusion using netting, shade houses or screens instead of harmful chemicals.
Actually, you should aim to be as close to nature and organic as possible, as pesticides and fertilizers may actually harm or kill your fish which are very sensitive to pesticides and phosphorus-based fertilizers which could cause algal blooms or suffocate your fish.
Trying to minimise our use of pesticides and fertilisers is an important aspect of environmental stewardship
[strawberries are a great choice for an aquaponics plant choice as the complex nutrients from fish waste encourage and support healthy fruit growth]
What Types Of Fish Can I Grow In Aquaponics
There are many different types of fish you can farm using aquaponics – but aquaponics is not limited to just fish.
Some freshwater fish that can be farmed in aquaponic systems are;
- Tilapia (The most common type of aquaculture animal used in aquaponics)
- Bass (large bass will need large tanks and eat a lot of feed!)
If you don’t like fish, other common aquaponic livestock include crawfish or yabbies (fresh water crayfish), Marron (giant freshwater lobsters) or other freshwater crustations like fresh water prawns.
[fresh water crayfish like this yabbie (cherax destructor) are a great choice for aquaponics stock, and are highly sought after for cooking]
Aquaponics is a great way to teach people about sustainable food production and healthy eating using permaculture principles; aquaponics can be used in both rural and urban settings, so it’s a versatile way to increase the sustainability and security of our food system.
What are you waiting for? Get started on your own aquaponics project today! There are plenty of resources available online, or you can join one of the many aquaponics forums to learn from other enthusiasts. Happy fish keeping!