In backyards, business spaces and community centres across Sydney, hobbyists and professional growers alike are increasingly turning to aquaponics as an alternative, relatively low-cost method for producing food in an urban environment.
By CHRISTINE BROWN-PAUL
Aquaponics is defined as the combination of aquaculture (growing fish in water) and hydroponics (growing plants in water).
“It’s a simple idea, borrowed from nature, but with extraordinary results for modern gardeners,” says Charles (Charlie) Bacon from ecolicious aquaponics.
“Basically, plants and fish grow symbiotically in a closed system. The fish live in the fishpond/tank while the water from the pond, enriched with fish waste, is used to feed plants in separate grow beds,” he says.
“The plants, along with healthy, naturally occurring bacteria, clean the water, which is then delivered back to the fish, being oxygenated along the way.
“Organic vegetables can be grown highly efficiently in the nutrient-rich pond water,” Charlie says.
“Fish, yabbies, mussels etc., can be grown in the closed system, providing a constantly renewable food source—and they are interesting to watch as well. No chemicals, no fuss, just fresh fish, herbs and vegetables.”
Charlie says that aquaponics has many benefits, including the fact that it uses 90% less water used than for a conventional garden.
“Aquaponics also offers five times the plant growth rate of a conventional garden,” he says.
Charles has worked on many aquaponics projects and is well regarded in his field.
“Ecolicious grew from the desire to help people integrate sustainable living into day-to-day life,” he says.
“We partner with highly skilled landscape architects, pond builders, permaculture consultants, nurseries, etc. The list is long, but the point is simple; we work with some of the best people in Sydney to get the job done right, first time.”
Charlie began experimenting with basic aquaponic (or bioponic) systems nine years ago; researching, designing and creating systems of varying complexities, eventually becoming focused on simple and sustainable.
“My first aquaponic project came from experimenting with food plants and a small pond on a balcony in a unit block nine years or so ago. I then moved to a house close to the beach so very sandy soil, a very small space and lots of paved and concrete areas,” Charlie says.
“I continued to expand my collection of aquaponic growbeds, ponds tanks, pipes, and livestock over the years. By combining fishponds and growbeds, I am able to grow a wide variety of herbs and vegies very efficiently in a small space with little effort… however, my ‘science experiment’ looked rather ugly.
“I realised that aquaponics could reach a far wider market if it could be integrated into the existing landscape and it looked ‘pretty’. Eventually, I quit my office job to follow my passion to help people grow food,” he says.
“As the popularity of aquaponics grew exponentially over the last six years in Australia, so did the complexity and the information overload.”
However, Charlie believes that aquaponics is far less complicated than is often described, for example, on the web.
“Find a couple old bathtubs, get some gravel and gold fish and give it a go. There is plenty of DIY info around,” he says.
“Fish welfare is your highest priority, keep stocking levels low for a few months, filter out as many solids as possible (fish poo), watch your pH, nitrite, ammonia levels and water temperature. Aeration is very important, so use aerators and cascades to get oxygen into the system.
“A great reference is Aquaponics in Australia,” Charlie recommends.
Kimbriki Eco House and Garden
Over the years, Charlie has constructed at least 50 personalised, unique systems and assisted in the design of many more.
“Some of my key projects include Kimbriki Eco House and Garden, my first public space system; Inner City Montessori School, which I constructed with Costa for a Gardening Australia episode; and a property in Mosman, NSW, which was entirely constructed of 40 or so polished recycled railway sleepers. It is now able to supply herbs and vegetables for a growing family, and currently stocks 70 silver perch,” Charlie says.
Kimbriki Eco House and Garden at the Kimbriki Resource Recovery Centre on the Northern Beaches of Sydney, showcases and runs workshops on many aspects of sustainable living.
“Ecolicious was challenged to create an ultra sustainable aquaponic system here, recovering recycled materials from across the Kimbriki Resource Recovery Centre,” Charlie says.
“This system will continue to grow as we experiment with other recycled materials, and aquaponic growing methods. “
Senior Ecologist at the Kimbriki Eco House and Garden, Peter Rutherford, was interested in having an aquaponics set-up at the educational centre.
“I was interested in aquaponics as it offers a natural way in which to produce food, using the nutrients derived from fish waste. Charlie created a fantastic set-up for us, which is a great example of a food growing system that thousands of people will be able to learn from and use in their own homes and gardens,” Peter says.
“Ninety-nine per cent of the recycled materials used in the construction of the aquaponics system were sourced on site. The set-up emulated a natural rock pond, using recycled rock and crushed tiles.”
Down to the detail
Charlie says he finds that media-based flood and drain aquaponic growbeds are the most robust simple system for average backyards.
“By using a structural box lined with high quality rubber pond liner, I can create any design. I construct a ‘bell siphon’ to regulate the water in the growbed and generally use 10mm river gravel (thoroughly washed) as the media,” he says.
“I do not use any PVC for ethical, health and aesthetic reasons—off-the-shelf PE (black poly) irrigation pipe and fittings do the job, and I prefer a ‘filter pond pump’, which pumps at least double the volume of the tank/pond each hour.”
According to Charlie, the biggest challenge with setting up aquaponic systems is sunlight.
“Plants need as much as possible to maintain health, however, fish ponds and tanks prefer little to no direct sunlight,” he says.
“Additionally, as all of my systems use gravity to return water back to the pond, it’s important to get a height difference, which is not always easy. The growbeds are often located a few metres away from the pond so I run pipes under footpaths and the like.”
A viable solution
Charlie believes that aquaponics presents a real solution for producing food in an urban environment.
“Aquaponics, like hydroponics, is a very viable solution for producing food in small spaces as it does not require soil, which is often degraded, sandy or clay,” he says.
“Once a system is established there is very little maintenance, however, fish health is a high priority so it is important to keep lower stocking levels until the system matures or ‘cycles’ over a few months.
“Australian soils are in general, nutrient deficient, and in a country often consumed in drought, water is a big issue. Aquaponics, like hydroponics, provides a soil-free, water-saving option for food production in an urban environment,” Charlie says.
“Most herbs and vegetables can be grown with aquaponics, however, with the initial high investment in setting up the system, it is best to grow high turnover crops( i.e. plenty of the common herbs and leafy greens), or as I say to clients, ‘grow what rots in the bottom of your fridge’.”
“The most popular fish grown in Australian AP systems are silver perch, however, trout are grown as far north as Sydney over winter. Barramundi and jade perch can be grown in warmer climates, while Murray cod, Tandanis catfish (my favvourite), yabbies, turtles and other species are also used (note the turtles are not edible, they just provide nutrients),” he says.
“Tilapia (illegal in Australia) is the most common fish grown throughout the world and much of the AP research is based on this, however, Australian fish require far better conditions.
“Ornamental fish such koi and goldfish are equally important in providing nutrients to plants and require far less work, considering many people in urban areas are not interested in eating the stocked fish, which can easily, and often do, become pets,” Charlie says.
FREQUENTLY ASKED QUESTIONS
Charlie Bacon from Ecolicious Aquaponics gives the following tips on aquaponics.
Q: How do aquaponic systems work?
Basic-type aquaponic systems (media-based) operate in the following way:
• Fish are grown in tanks or ponds, nutrient rich water from the pond is pumped into grow beds
• The grow beds are filled with media (gravel or expanded clay), which allow the growth of beneficial bacteria
• Plants grown in the media use the good bacteria in the water, which has been converted to nitrate by the bacteria
• Water, now cleaned of nutrients, is drained back into the pond; and as grow beds empty, the roots are oxygenated.
What plants can be grown in an aquaponic system?
Nearly every plant and herb grown in soil, including fruit trees, have been successfully grown in aquaponic systems across the world, from everyday herbs and vegies to cactus and aloe vera, citrus trees, passion fruit and even mushrooms—pond plants and edible water plants can also be grown in your pond/tank. Note, however, these will take nutrients away from the grow beds—most importantly, grow what you like to eat.
What type of fish?
Silver perch, jade perch, barrumundi and trout are the most common edible fish in Australian aquaponics systems. Gold fish and koi are popular ornamentals—we recommend a few goldfish (feeder fish) until your system fully cycles.
Yabbies, mussels, shrimp are also great additions. You will need to consider your climate when choosing fish and keep a low stock until your system has properly cycled and built up enough beneficial bacteria—and you are confident in your understanding of aquaponics.
You don’t have to eat your fish, just make the most of the poo for growing herbs and vegetables.
What fish food?
Aquaculture pellets are the most popular fish food. Worms, black soldier fly larvae, duck weed and algae are more sustainable options, but harder to grow in large enough quantities.
Seasol and worm juice can be added to provide the plants with more nutrients— it can take a couple of months or so for the plants to thrive. Do not add too many fish until the system has cycled properly. Once good bacteria has matured, the system will remain highly productive for years to come.
How long until an aquaponic system is productive?
Systems take a good month to cycle and for the good bacteria to build up.
Ponds and aquaponics?
Ponds can be easily retrofitted to an aquaponic system with the addition of a grow beds. Ponds must be lined, rather than earthen, as soil will affect the biology. You don’t need silver perch and other edible fish, as ornamental fish are just as suitable in providing nutrients to the grow beds. The grow beds will also keep the pond water clear.
As ponds are often subject to sunlight, it’s important to ensure there are places for the fish to hide. Pond plants will take some of the nutrients from the grow beds—regularly check pump flow rate to ensure leaves don’t clog your pump. Don’t panic if your pond appears green after a lot of sunlight, especially if your grow bed bacteria has not matured.
Is aquaponics complicated?
Basic systems are easy to use and lower stocking rates are quite safe, with limited instructions. As you read and become more experienced—and your good bacteria matures—you can start increasing fish stocks. Once you become addicted, you can incorporate more complicated systems.
Always over engineer your system, and buy high quality pumps and aerators, as leaks and other failures will kill your fish. Also consider the structure under your growbed, half a tonne of falling gravel will hurt. Tanks and ponds over 300mm deep have similar safety issues as swimming pools and should be fenced, covered or have a grate, especially if accessed by the public or small children.
Buy your fish from a local and recommended supplier. Respect the welfare of your fish. Aquaponics in Australia by Shannida and Matt Herbert is a great reference.
About the author
Christine Brown-Paul is a Sydney-based journalist with a special interest in the environment and sustainable technology. Email: firstname.lastname@example.org Ω
PH&G October 2013 / Issue #137