by Richard Smith
In this article, I want to talk about Aquaponics, its clever way to use natural cycles to produce food, and its inspiring potential for engaging children in learning natural sciences.
So first of all, what is Aquaponics? In Aquaponics, fish waste is used to make fertiliser instead of chemicals to feed the plants. It allows you to grow just about anything, whilst making intelligent use of natural processes. After hearing about the concept, I had been so impressed by the idea of growing food with fish waste that I was determined to try it out, even with limited physical resources.
Having been well trained in the permaculture approach to creating a new project, I was committed to planning my first aquaponic system to the finest detail. It had “been a while” since I actively applied permaculture principles. However, the planning process and thinking through the principles was a key element that made the project a success (see below). Chatting to the right people at the right time provided me with the great opportunity of installing a basic entry level system with minimal outlay. Thanks to my use of permaculture thinking, and a few lucky circumstances, I quickly found just about everything I could need: a suitable site; financial, technical and moral support; access to organic seeds and even a supply of free fish (I was suddenly plunged into the world of fish care by the kind donation of 35 mixed goldfish)!
After a lot of researching and learning, I am now managing three hobby size aquaponic systems. Some of my favourite things to grow are spinach and leafy greens these days, as well coriander and thai basil. I am getting a few meals per month from the greens, which I am very pleased with. However, my personal main purpose is to explore different systems and hone my own skills with the fish, plants and the microbes. Management is needed continually, but through the clever use of resources I only need to spend two days per week (about 6 hours in total) in managing it.
Aquaponics as a learning tool for children
Aquaponics is a great example of a permaculture system, in which different elements support each other, and food is produced in a creative, sustainable way.
However, the multiple uses of Aquaponics extend beyond physical benefits: It holds incredible potential to improve on people care and learning, namely improving children's experiences of learning about science. It was my own experience of learning so much about water chemistry as part of the process, which inspired me to the idea of promoting Aquaponics as a teaching tool in schools. It provides a fun and hands- on medium to experience science in action, as well as a great opportunity for inclusion of disenfranchised learners. It is the ideal component to place in every science classroom for the teaching of a wide range of physical, biological and chemical topics. When the tasks involved are broken down further, it comprises a wonderful set of skills related to physics, biology, chemistry, design and technology. The hardware is straightforward but demands attention in setting up. If things go wrong it provides a great problem solving exercise, and as such, a great way to learn.
|The basic aquaponic cycle|
Taking it further
For those of the readership, who may be interested in trying out this integrated approach to producing plants and fish together, there is a wealth of information on the internet, a number of books written by practising Aquaponicists, and a growing number of enthusiasts that will probably be happy to spread the word of this rewarding and addictive approach to producing food, just about anywhere with limited resources.
Book: Aquaponic Gardening: A Step-by-Step Guide to Raising Vegetables and Fish Together (by Sylvia Bernstein )
Book: Backyard Fish Farming (by Paul Bryant)
If you would like to find out more about this project, please get in touch with Richard!
APPLYING PERMACULTURE PRINCIPLES
For the purposes of this letter I’m revisiting the Permaculture Principles and exploring my own thoughts in the light of my experiences as my own AP systems have come into being.
1. Observe and Interact
Keep an eye on the livestock and remove uneaten food, check the plants for pests and diseases. Test the water quality for crucial parameters such as temperature, toxins like nitrite and ammonia and the nitrate required for plant food. Act accordingly by changing water if necessary, research and study so that the biology and chemistry of the ecosystem is understood as much as possible and harvest accordingly. Feeding the fish is great fun but if the food gets left uneaten it’ll add to waste management problems, little and often is fun with my fish as they don’t tussle too much with each other, and so on. Aquaponics is very interactive!
2. Catch and Store Energy
Use available sunlight for plant growth, to keep the water warm and possibly to run pumps. Consider a header tank to store potential energy and as a heat sink. Consider a sump tank to condition the water using biological means and provide further opportunity for production of materials. Apply insulation where appropriate. Use a polytunnel to extend the growing season. Use waste materials to create compost and use to enhance future fertility in and around the system. My own systems capitalise on indoor setting in a retail situation. Light and heat are available but there is noise and vibration which disturbs the fish during shop hours.
3. Obtain a Yield
Harvest the fish as food or breed ornamental species. Obtain a series of yields by integrating multiple species and growing food for the system within the system. Produce edible plants or those with a financial or aesthetic benefit. Remember the non-financial benefits of keeping fish and nurturing plants and the therapeutic and social aspects of horticulture. In my case I have been impressed by the range of factors needed for good management of an AP system and translated this to be the major yield for educational settings.
4. Apply Self-regulation and Accept Feedback
Learn from mistakes and continue to study as this beneficial technology becomes more widespread. Be ready to accept personal limitations and adapt to changes as the ecosystem system matures. The principles of aquaponics are straightforward but the application within a given set of circumstances is likely to be an on-going process that will evolve and change.
5. Use and Value Renewable Resources and Services
Grow food within the system and continue to look for ways to take advantage of solar power, heat from bacterial activity and gravity driven water power. Consider how other disciplines or traditions can inform current practices. For example, use biodynamic techniques to enrich the water before adding to other plantings. Use hydroponics to optimise use of the water from the fish tanks for growing tomatoes or other favourite crops.
6. Produce no Waste
Use all possible outputs from the system. If nitrate, or ammonia, rich water needs to be replaced, this can be used to water houseplants or other productive plants. Dead fish can be used as nitrogen rich fertiliser or as feed for invertebrates. Recirculate and recondition water by oxygenation and circulation. Waste plant material can be fed into a wormery.
7. Design from Patterns to Details
The nitrogen cycle comprises the flow of resources for both the assimilation and break down of the component species involved in this small ecosysytem. Aquaponics, though this term is recent, began by using pond water to irrigate crops and has developed into a range of applications of this basic principle. Start with an outline and progress from there. AP systems, just like a healthy aquarium, take time to mature as the bacteria develop and the nitrogen cycle becomes established. Inevitably this will require a response from the human components of the system and the details will naturally appear from the general principles. This is an on-going learning process. Variations on the theme have informed our understanding of some of the beneficial aspects of growing food on chinampas in South America and organic rice paddies in Java.
8. Integrate rather than Segregate
Consider the needs of the fish, the bacteria and the plants. Innovations may allow greater integration to take place between needs and opportunities to produce in accordance with these needs: we could grow duckweed and worms to feed the fish; use the water to feed further plants outside the AP system; allow outside factors to have a beneficial influence like situation in a sunny or cool location; use local resources including people and share the skills and yields that this benefit may spread.
9. Use Small and Slow Solutions
This is absolutely crucial when working with livestock. Await feedback before making further changes if adjusting pH and adjust water quality gradually and avoid stressing the fish. What many people fail to appreciate when new to fish keeping is how susceptible they are to stress. They are sensitive to light and vibration. Fish live in an environment where they are weightless and are rarely subjected to any physical contact until predated. Shadows alert them to the presence of a predator and often provoke an urge to escape. A slow evolution when meeting problems may allow a good fit to circumstances, if it doesn’t work it can be changed until it does and remains sustainable.
10. Use and Value Diversity
Within aquaponics there are an unlimited number of ways to achieve a healthy ecosystem. Ideas from hydroponics, aquaculture and hydrology have provided a wide range of systems that deliver yields of various products. Watercress grows well using nutrient film techniques (NFT), Lettuces are produced using Deep Water Culture (DWC) and this can be integrated with tropical fish production. An open mind and curiosity is a great asset. There are perhaps many refinements to AP systems that may come from presently unconnected disciplines. Environmental enrichment may be provided by the interaction between different species within the ecosystem.
11. Use Edges and Value the Marginal
Consider the edge effect at the margins of the basic components: the plants/fish interface involves the movement of water and it’s an opportunity for oxygenation and production of sound. (Water features are popular partly because of their soothing sounds). As the water moves between the fish and the bacteria in some designs, using a biological filter box or sump tank for instance, there’s a further opportunity to remove solid waste for use as plant food or to feed invertebrates.
Aquaponics itself is on the edge between aquatic environment/aquaria/aquaculture and hydroponics/ horticulture/organic food and the scope for combining beneficial elements of these diverse topics seems endless and potentially rewarding.
12. Creatively Use and Respond to Change
Aquaponic systems take time to establish and continually evolve. There seem to be innovative ideas popping up in every conversation with fellow growers and aquarists. Living things are constantly changing and in this case they are simply “harvested” at a certain point in that process of change. In the UK climate we have a fairly predictable seasonal pattern that may reduce productivity in winter. This provides downtime for planned maintenance, disease and pest control or maybe just a break and opportunity to make changes to the design and function of the system.
About the author: Richard is a member of the Permaculture Association, a former teacher at Warwickshire College of Agriculture and volunteer at the Heritage Seed Library based at Garden Organic, Ryton. He also works part-time at the local CSA and grows leafy greens and herbs in his aquaponics systems. In an attempt to propagate aquaponic know-how he has promoted and recently installed a custom built system in a local primary school for growing veggies for after-school cookery classes. Richard is happy to answer basic questions related to aquaponics and is open to offers of work related to permaculture and sustainable food production in order to raise funding for further projects. If you want to get in touch with him, please click here.