Co-founder of foodqube Australia Rob Armstrong shares his insights into the challenges and rewards of backyard aquaponics systems
Aquaponics is a growing technique that combines elements of both hydroponics and aquaponics. It harnesses a symbiotic relationship that exists between fish and vegetables, where the fish provide nutrients required for healthy plant growth and the plants filter the water for the fish. The real work is done behind the scenes however by millions of bacteria that colonise the growbed and that work hard to process the waste that the fish produce (ammonia) and turn it into plant food (nitrate). This blog post has been written to explore the unique challenges that present to the aquaponics gardener and to provide some insight into how these challenges might be met, so that aquaponics can continue to develop as a sustainable alternative growing technique into the future.
Reconciling the needs of fish, plants and bacteria
Fish, plants and bacteria all have their own preferred water quality parameters such as temperature and pH. Balancing these often competing requirements can be a challenge. Traditionally in hydroponic food production, growers can exert a great deal of influence over their water chemistry in order to achieve a desired result however in aquaponics management actions need to be able to satisfy the requirements of each living component. So why bother? Well it is this complexity that is at the very heart of what makes aquaponics such a resilient and self-regulating growing technique.
It is the interactions between the fish, plants and bacteria that further closes the loop on the water, nutrient and waste cycles, thus making aquaponics a very attractive alternative. Success in this area will therefore depend on the ability of growers to firstly understand and then to integrate the needs of each living component within the system. Although our appreciation for these interactions is growing there are still a great many gaps in our knowledge that will need to be filled in order to realize the full potential of this growing technique.
Addressing knowledge gaps and conflicting messages
Due to the relative infancy of aquaponics as a mainstream growing technique a great deal of unsubstantiated claims are still making their rounds in backyard grower’s circles. This often-conflicting information is making it difficult for the beginner gardener to develop an informed position on how to best manage their home system. An example of this is illustrated by taking a look at grow bed depth. During the pioneering stages of aquaponics it was professed that a grow bed depth of at least 300mm+ was essential to support a healthy colony of bacteria in an aquaponics system.
There is however a lack of any real evidence to support this claim and therefore I believe that early adopters are using a lot more of this material input than is actually required. The same can be said for electricity inputs to a system where people are using over sized pumps and running them for excessive amounts of time due to currently accepted practices in plumbing and grow bed design. This all brings me to my next point, which is how we can look to material and energy flows in a system for opportunities to further close the loop on aquaponics as a growing technique.
Material and energy flows
Aquaponics provides an opportunity to shift away from linear (open loop) systems, in which the inputs to a system eventually move through and become a waste, to a closed loop system where wastes can become the inputs to a range of other processes. This is in sharp contrast to conventional farming practices where losses of water, nutrients and wastes are a generally accepted practice. The dichotomy that exists however is in the additional material inputs that are required to both set up and maintain an aquaponics system.
It is therefore hugely important that consideration is given to the types of materials that are used during the construction phase of an aquaponics venture as well as looking at the inputs that are used ongoing. We have already touched on a couple of ideas in the preceding paragraph but there are still huge number of opportunities to improve how we go about gardening aquaponically including; water and energy procurement, fish food and waste management, management of additional nutrient requirements and material inputs used throughout the construction and maintenance phases.
Harnessing the benefits of aquaponics
Ultimately the success of aquaponics at the backyard level will be determined by its ability to reward the gardener for their time, energy and resources spent. Learning to harness the natural efficiencies of aquaponics will play a crucial role in how successful aquaponics is into the future. This success will also depend on the ability of leaders to provide a consistent and strong message to gardeners around current best practice management. Lastly and most importantly consideration needs to be given to the material and energy flows that make up the system.
Aquaponics in permaculture design
There is much controversy that exists around aquaponics and how it fits within a permaculture design framework. Much of the discussion however has been very one dimensional in nature and so in order to provide a whole of systems comparison I will attempt to assess aquaponics against the 12 defined principles of permaculture.
|Observe and interact||Aquaponics offers people a connection to and an appreciation for the food they eat, like nothing else. The amount of observation and interaction required to maintain a healthy system has it score very highly in this area.|
|Catch and store energy||Aquaponics is able to in-directly capture and store energy in the form of food. In fact fish have a markedly better feed conversion ratio than any other farmed livestock.|
|Obtain a yield||Aquaponics is an intensive form of food production and can be very high yielding.|
|Apply self-regulation and accept feedback||The ecosystem that exists within aquaponics is very much self-regulating. As more nutrients enter the system, bacteria and other organisms like fungi and worms naturally colonise to process the additional nutrients.|
|Use and value renewable resources and services||This is a definite point of contention and the outcome really depends on the system itself i.e. has renewable energy been used to power the pump; has the system been built from recycled materials; has a low impact grow media been used & does the system try to minimise its electricity use. The super-efficient use of water and nutrients in aquaponics needs also to be recognised here.|
|Produce no waste||The inherent closed loop nature of aquaponics means that it is free from any wastes and is a big thumbs up here.|
|Design from patterns to detail||Aquaponics has helped to identify a number of shortcomings in our current food system and it offers people an opportunity to do something about it if they so choose.|
|Integrate rather than segregate||Aquaponics is a great example of a working ecosystem. You feed the fish, the fish produce wastes, bacteria convert these wastes into food for the plants, the plants take up the available nutrients thus cleaning the water for the fish.|
|Use small and slow solutions||What is remarkable about aquaponics is its uptake by the home gardener. The slow but steady growth that has occurred in the backyard farming setting is allowing this technology to mature at a safe and sustainable rate.|
|Use and value diversity||Aquaponics thrives on diversity. The greater the number of fish and plants in the system the more resilient it will become. Diversity in organisms like bacteria, fungi and worms will also create a healthier system.|
|Use edges and value the marginal||Aquaponics is definitely an outlier. Only recently have people really started to experiment with different growing techniques and technologies. I believe that it is important to continue developing knowledge in this area as it just may be a critical part of the overall food system into the future.|
|Creatively use and respond to change||I believe aquaponics is still very much in its infancy and that we are about to see an explosion of creativity in this space as people begin to reinvent and redesign aquaponics as an urban farming practice.|
Some ideas for those at home who want to further close the loop:
Build your own system from recycled materials; There is enough wood in a single double pallet to build a 300 plus litre aquaponics system. All you need to do is find a second hand pallet, salvage the wood and build a rectangular frame that will house both your fish and grow bed (fish tank can be made using a pond liner & grow bed can be made using a hydroponic grow tray). Another great idea is to use recycled corrugated iron as a wall material! I managed to do a proof of concept for our kits in just a single afternoon.
Make your own fish food; Not only does making your own food give you control over what goes into it but by creating a fish food that is designed specifically to feed your plants rather than your fish it will inevitably boost the macro and micro nutrients in your system, thus ensuring good vegetable production.
Grow your own fish food; Duckweed, black soldier fly larvae (warmer climates) and any green leafy veggies will all provide you with a food source that can help to supplement or replace commercial feed altogether.
Reduce your power inputs; Run an intermittent flood and drain system rather than continuous ebb and flow system. This can be set up on a timer to run only 15 minutes of the hour and can reduce your power input by almost ¾.
Reduce the depth of your grow bed; Rather than going 300mm deep with your grow bed, try a much shallower bed of say 100mm. Not only will your system be more compact, lightweight and easier to transport but it will also reduce the embodied energy of your system.
Use low input additives; rely on egg shells, banana peels and other natural products to correct deficiencies in your system. Egg shells will boost the calcium in your system and banana peels will boost your potassium.
Choose a hardy fish species; In terms of fish species I advocate strongly for the use of Silver Perch throughout the cooler states and Jade Perch for the warmer States. This is due to their wide tolerances to swings in water quality and the fact that they do well in tank culture.
Thanks for reading!
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You might also want to check out fish options at Milkwood.net
All photos supplied by Rob Armstrong or sourced from foodqube
- Aquaponics is Not Suitable for All Crops. ...
- Cost of Electricity. ...
- Set Up Costs. ...
- Expensive to Upscale. ...
- Needs Technical Knowledge. ...
- Not A Lot of Fish. ...
- One Part Fails, It All Fails. ...
Aquaponics combines aquaculture (fish, prawn, snails) with hydroponics (the cultivation of plants in water), which creates a self-sustainable system capable of producing food. For the system to work, nitrifying bacteria must be added to the fish's water.
It is sustainable and generally environment-friendly because it doesn't require acres of land and wasteful irrigation. Despite this, many people practicing a vegan lifestyle would question the welfare of the fish and believe that aquaponics is not as cruelty-free as it may appear on the surface.
Plus, aquaponics systems are beneficial because they don't harbor soil pests, therefore no pesticides are necessary. Plants Grow Faster – Because plants have access to nutrients 24 hours a day, they grow faster. For example, the aquaponic system speeds up the growth of lettuce from two months to one month.
Some of the ones to avoid growing hydroponically are root vegetables such as turnips, onions, garlic, carrots, and rutabaga. Typically, these species will need plenty of soil for their roots to spread out in search of nutrients and moisture.
This is a common question that circulates in forums, and for good reason. Aquaponics is a more environmentally sustainable method of growing than conventional agriculture, but if it's not financially sustainable as well, it is not a viable venture for most growers.
Aquaponics doesn't require fertilizer or added nutrients to be sustainable. Aquaponics is a closed system by nature whereby the fish and vegetation rely on each other for the necessary nutrients to thrive. The only addition to the environment is quality food for the fish.
Tilapia is one of the best fish to raise in aquaponics because they are hardy and can adapt to their environment and withstand less than ideal water conditions. They are resistant to many pathogens and parasites and in handling stress.
Aquaponics is a sustainable method of raising both fish and vegetables. It is popular with individuals, entrepreneurs, educators, missions and governments. Furthermore, with this type of indoor farming, you grow substantially more food with less water, land and labor than traditional agriculture.
It helps provide food, shelter, energy, and other resources sustainably. Integrating aquaponics into your permaculture system is something permaculture farmers can do to boost sustainability. It provides another food source and feeds into the closed-loop system of permaculture.
A properly designed and maintained aquaponic system should not produce any foul smells. When growing fish, you can expect a slight odor, but it should not be offensive.
- Plants Are Dying. ...
- Too Many Fish in the Tank. ...
- Pest Problems. ...
- Algae Growth. ...
- Dead Fish. ...
- Water Temperature. ...
- Contaminated Water. ...
- Plant Nutrient Deficiency.
Aquaponic vegetables are often much tastier than the same vegetables grown in soil. Vegetables grown aquaponically are organic and healthy with no chemicals or man-made fertilizers fed to them, which enables them to taste even better than ordinary vegetables.
Therefore, as the experiments of this study resulted in a good amount of P O5, the nutrient solution derived from human urine can facilitate the growth of greener and tougher plants compared to planting in inorganic hydroponic systems. Still, such an amount is suitable for hydroponics.
The usual period for growth is around two months but with the aquaponics system, it typically takes only one month. In some tests, vegetables and herbs have grown even up to four times faster with an aquaponics system compared to a hydroponics system.
Broccoli has a huge array of health benefits, making it a good choice for your aquaponics system; although maybe not for your first attempt at growing anything. In fact, broccoli demands a lot of nutrients, making it a moderately difficult plant to grow.
Lettuce grows so fast in aquaponics that it can be harvested in as short as two weeks or when you notice the heads and leaves are large enough for consumption. It is recommended to harvest early in the morning while the leaves are crisp and moist.
Which is more profitable? Since overall yield is higher in Aquaponics, therefore it is the most profitable technique of soil-less agriculture. Which one is more commercially viable? Definitely, aquaponics are more commercially viable than aeroponics and hydroponics as it gives both plant and fish yields.
5 lakh to Rs. 15 lakh. While the cost of setting up such a farm is higher than conventional farming that the operational cost is much less because there is no need for fertilizers.
Backyard or DIY Aquaponics Systems
If your goal is to produce enough crops and fish for your family, a small scale aquaponics system in your backyard is worth the investment. The requirements for a domestic aquaponics system is not as expensive as the commercial ones.
The most important ingredients in your Aquaponics system are nitrogen, phosphorus, potassium, calcium sulfur, and magnesium. Your plants will also need trace amounts of boron, copper, chloride, zinc, molybdenum, iron and manganese.
Many aquaponics growers widely use lava rock as grow media because they are lightweight and have plenty of surface area. Lava rocks are typically pH neutral, porous, and provide good drainage and aeration to the system.
By developing aquaponic systems in which wastes from fish and crustacean farms can grow edible seaweeds on substrates that can be grazed by estuarine mullet or rabbit fish – each of which can be fed to more valuable species.
It is also one of the best choices for edible aquaponics fish since it is delicious, and it can be prepared in several ways. It is high in protein, and it grows quickly despite poor water quality. Some of the other advantages of tilapia are its ability to reproduce quickly and its omnivorous diet.
Strawberries are among the best plants to grow in aquaponics systems because they are easy to grow and take only a small space to grow and grow larger and juicier, and taste better.
Some of the simplest things to do within this list are to insulate tanks, growbeds and pipes in colder climates so that the water heat is not easily escaping. We often hear people say that they want to bury their tanks in the ground in order to use the ground as additional insulation and thermal mass.
Since aquaponics doesn't employ the use of soil, most of the nutrients that the plants need come from the fish waste that is converted by bacteria into nitrates. In cases where plant deficiencies occur, organic fertilizers such as bone meal and banana peels are used as supplementary nutrient sources.
To get started with aquaponics, a grower must understand the essential components of aquaponics systems. These include the three main components: fish, plants, and bacteria, and the secondary components, which include the fish tank, grow bed, pumps, and plumbing.
Low Water Usage: One of the significant benefits of aquaponic growing is minimal water is wasted compared to the traditional growing method, like soil gardening. Although the name implies 'water,' aquaponics uses approximately 90% less water than conventional agriculture.
- Observe and Interact with Nature. ...
- Catch and Store Energy. ...
- Obtain a Yield. ...
- Apply Self Regulation and Accept Feedback. ...
- Use and Value Renewable Resources. ...
- Produce No Waste. ...
- Design From Patterns to Details. ...
- Integrate Rather Than Segregate.
Aquaponics involves growing fishes and plants together within the same environment, which is considered to be a sustainable process. On the other hand, hydroponics is a gardening method that allows for plants to be grown without the use of soil.
However, the ammonia in aquaponics systems can be removed by the nitrifying bacteria that converts ammonia into nitrites and then into nitrates by nitrification. Nitrification performs optimally when the dissolved oxygen levels are high, and the organic matter (produced by uneaten fish food and other wastes) is low.
Growing Time: How Long Do Tomatoes Take? Generally speaking, aquaponic tomatoes grow about twice as fast as soil-grown tomatoes. That means they grow to full size in as little as four weeks. Outside of aquaponic systems, they take around six to eight weeks to reach the same level of maturity.
Your aquaponic system is lacking the nitrifying bacteria that converts ammonia into nitrate. You should consider adding nitrifying bacteria to your system by: watering plants with water collected from a nearby pond, which will naturally contain the necessary bacteria, or by buying bacteria.
Should you pee in your aquaponics system? - YouTube
Do Aquaponics Fish Need Light? Fish do not need sunlight or other forms of light to survive in an aquaponics system. However, adding light to your fish tank may improve fish health and egg production, as most fish require light and dark periods. Fish are healthier if they get daily exposure to sunlight.
Interplanting Garlic, Chilli, Chive, Mustard and Onions in your aquaponics will most likely help repel fungus and pests. If aphid infestation occurs, you can also use the fruits to make a spray, but use sparingly and be careful not to get this in the aquarium water.
First, Hydroponic environments are often warm and humid, just the kind of conditions tomatoes like. They produce lots of big, juicy tomatoes… which means more water and cellulose, and less flavor per bite.
Growing Beans and Tomatoes in Aquaponics - YouTube
An aquaponics system can grow almost any plant. However, the popular choices for medicinal herbs grown in aquaponics are Basil, watercress coriander, sage, lemongrass, parsley, chives, thyme, oregano, mint, chamomile, rosemary, and more.
As a general rule, it is recommended that the fish tank volume should be equal to the grow bed volume, which makes the grow bed to fish tank ratio approximately equal to 1:1. The most directly related factor in the fish to plant ratio is the feeding rate.
Water filters are not necessary for an aquaponics system. However, adding a filter may improve the health of your fish and plants.
The most common algae that causes problems in aquaponics are the green algae. Algae can cloud up the water in your aquaponics system, foul pipes, and pumps and can cause oxygen depletion and pH swings.
Aquaponics Don't Rely on Artificial Fertilizers
The fertilizers used in agricultural produce is not only hazardous for the environment but also costly for farmers. However, in aquaculture, the reduced use of fertilizers safeguards the environment and promotes less use of herbicides and pesticides.