Aquaponics is one of the most eco-friendly and sustainable methods of growing food.
The great thing is that it can be done even when space is limited.
In this guide, we’re going to take you from aquaponics newbie to expert.
In shot: if you want to get started with enjoyable and sustainable form of gardening, you’ll love this guide.
What is Aquaponics?
The Aquaponic Gardening Community defines aquaponics as:
…the cultivation of fish and plants together in a constructed, recirculating ecosystem utilising natural bacterial cycles to convert fish waste to plant nutrients. This is an environmentally friendly, natural food-growing method that harnesses the best attributes of aquaculture and hydroponics without the need to discard any water or filtrate or add chemical fertilizers.
Aquaponic Gardening Community, November 2010
Ultimately, aquaponics is about taking “waste” from one system and using it as a resource for another.
While it’s currently a trendy concept in the gardening and self sufficiency community, the idea is almost as old as time.
First documented by the ancient Aztecs, aquaponics is the process of creating a system that imitates nature with the aim of growing plants, fruits and vegetables.
With no weeding, watering or digging, aquaponics is a low maintenance and environmentally friendly way to grow your own food.
In fact, aquaponics is so easy that you can create a mason jar aquaponics system and grow your own plants without any complex system.
Let’s take a look at the two main concepts.
Aquaculture (the ‘aqua’ part of the system)
Aquaculture is the growing of aquatic animals and plants in fresh or salt water.
The history of aquaculture dates back as far as the ancient Chinese who would catch young fish in the wild and store them in artificial environments to grow.
Aquaculture provides the food and nutrients for our plants to grow.
Hydroponics (the ‘ponics’ part of the system)
While the majority of tomato, basil and lettuce produced around the world is grown in a hydroponic system, many people associate it with growing marijuana.
In a hydroponics system, plants are grown with no soil, using water and chemical nutrients to grow the plants.
Plants grow extremely well in a hydroponic system as the roots are constantly bathed in highly oxygenated, nutrient-rich water.
Many of the system setups in aquaponics have their roots in hydroponics.
Hydroponics is the system used to grow our plants.
What are the benefits
With both global warming and global population growth spiralling out of control, there are real pressures being placed on the World’s food supplies.
Not only are there more mouths to feed but it’s becoming harder to growth the food to feed them.
Aquaponics is a sustainable, low energy system for growing food even when space is at a premium.
With no need for soil, aquaponics systems can be setup pretty much anywhere.
What you need to start
Since you’ve got this far, I’m going to assume that you’re sold on the idea of aquaponics and can’t wait to get started.
Let’s take a look at what you need to build your own system.
We’ve split out list out into two main sections:
- Hardware – the stuff you need to build the physical structure
- Software – the fish, plants, bacteria and worms you need to grow the plants.
If you’re looking for a great recommendation on aquaponics books for setting up your own system, we recommend Aquaponics: How to Build Your Own Aquaponic System by Celine Walker.
Grow media is just a fancy way of describing what your plants grow in.
In traditional gardening, the grow media is soil while in aquaponics, most gardeners choose to use either gravel, shale or expanded clay.
The grow media in aquaponics takes all that’s good and beneficial about soil and builds on it.
- Structure and stability for the roots of our plants
- Biofilter for the solid waste
- Home for worms
- Air and water exchange
- Temperature moderation
If you choose to use a different grow media, keep in mind that:
Your media should not change the pH of your water
Marble and limestone are bad choices for a grow media as they leak our calcium carbonate into your water which can create a high pH environment.
Your media should not be organic
Over time, organics such as soild, moss and coconut coir decompose which can lead to big fluctuations in the pH level of your water and the amount of nutrients it contains.
Your media should be properly sized
The skill in choosing the right grow media material is finding something that’s the right size.
A media that’s too small or dense such as sand will soon become clogged with waste and not let enough air cycle into the water.
A media that’s too large wont provide enough structure for the plants to take hold.
The ideal size for your media is around 12-18mm in diameter.
While the media is home for your plants, the water is home to your fish.
Out of everything in your system, it’s the water that can make or break your setup.
And when it comes to water there are four things to keep in mind
Most of us aren’t lucky enough to use a water purifying system when getting started which means we need to take a few steps to make the water as pH neutral as possible.
The first step is to test your water to see what the pH level is.
While there are some affordable pH testing meters available, initially you’ll be able to get away with using these testing strips.
If your water is coming straight from the tap, there’s a good chance that your water will be around pH7 (neutral). It will however contain chlorine.
Don’t worry, removing chlorine is as simple as filling your tank, turning on the pump and letting the water cycle through your system for a couple of days.
You’ll also benefit from putting more air into the water which speeds up the removal through a process known as “off-gassing”.
If you want to get a bit fancier you can use a dechlorinating filter and fit it directly on your garden hose removing the need to cycle the water for a few days.
The temperature of your water will be depend on the type of fush you use.
We’ll go into more detail about choosing the right fish below but the general rule of thumb is choose fish that do well in your climate.
Water heaters are a nessecity for most of us to help ensure that a constant temperature is maintained regardless of the season.
Keeping your water oxygenated is a crucial part of your setup.
Measured in parts per million (ppm), oxygen is critical for the health of your plants, worms, bacteria and fish.
The more oxygen that’s in your water the better the your system will be.
Water oxygen levels can be affected by:
- Temperature – colder water holds much more oxygen than warmer water
- Altitude – Oxygen is more easily disolved into water at low altitude
- Salinity – More salt in the water decreases the amount of oxygen that can be dissolved.
pH is measured on a scale of 0 to 14, with 0 being the most acidic and 14 being the most alkeline.
Water is neutral with a pH of 7.
With a number of variables in your system that are all capable of changing the pH of your water, you should aim to keep the water pH consistently between 6.8 and 7.
This helps plants, worms, bacteria and fish all thrive within your system.
Fish are the heart and soul of your aquaponics system.
All they ask is that we keep their water clean, warm and neutral and that we feed them.
In return they give our plants the food and nutrients they need to grow while also providing a little joy to our hobby.
Unlike the goldfish that you might have kept as a child, aquaponic fish are much easier to keep as the water is naturally filtered and disease is much less common.
The biggest descision you’ll need to make is which fish you choose.
In North American and Europe there are four popular choices:
- Tilapia – the most commonly used fish in aquaponics, tilapia like warm water but don’t have high oxygen requirements. If you’re interested in harvesting the fish they typically reach maturity after 9-12 months and taste good!
- Goldfish – if you’re not interested in eating your fish then opt for goldfish. They are tough as old boots and thrive in a wide veriety of environments.
- Catfish – easy to raise, grows quick and tastes great.
- Koi – Koi add a bit of beauty to your system and once mature can be sold off for some added income.
Being the amazing system that it is, the vast majority of plants thrive in an aquaponics system.
The only known exceptions are those plants that prefer acidic sould such as chrysanthemums and those the prefer basic soild (above 7.0).
While you certainly can grow subterranean plants or root vegetables they often look a little “off” as they have a tougher time expanding when in gravel.
That said, salad, fruits, herbs and even trees all grow fantastically well and are ideal for beginners.
Bacteria & Worms
If fish provide your plants with food, it’s the bacteria and worms that help give them live.
Once your system has been fully cycled and the fish have been introduced, you should add a hand full of composting worms as they’ll help to break down the wate products within your system.
Inside your grow beds, the bacteria and worms work to convert the fish waste into michelline star quality plant food.
A good aquaponics gardener focuses just as much on bacterial health as he or she does on the water or their fish.
Without a healthy colony of bacteria, plants would be left without food and fish would be left to die in their own toxic waste.
While thousands of different types of bacteria will call your system home, there are two that are the real super stars of the show:
Nitrosomonas and Nitrospira.
These two bacteria belong to a family of bacteria called “nitrifying bacteria”.
When you being cycling your system it’s these two bacteria that you’re looking to attract.
One of the most important things that you can do is “cycle” your system.
Cycling is the process of kick-starting the nitrogen cycle so the bacteria start converting ammonia and nitrites into food that your plants can consume.
Your system is fully cycled when there is no, or almost no measurable ammonia or nitrates present.
There are two ways to start cycling:
- Add ammonia yourself
- Let the fish naturally add the amonia for you.
Ammonia is toxic to fish and getting the right amount for your tank size can be a headache.
Typically the cycling process takes four to six weeks but it’s important that during this phase you take samples to know how close to completion your water is.
During the monitoring process you need to keep an eye on nitrite, nitrate and ammonia levels to ensure that they stay within a safe range.
Once you see ammonia and nitrite concentrations have reached around 0.5 parts per million or lower, your system will be fully cycled and aquaponics can begin.
If you’ve opted to manually introduce ammonia then at this stage you know your water is safe to add fish.
API FRESHWATER MASTER TEST KIT 800
The Bottom Line
So there you have it – you’re now ready to start building your first aquaponics system.