Aquaponics is an exceptionally sustainable method for cultivating crops that integrates both aquaculture and hydroponics into a single system. After installation, there is minimal need for maintenance or labor.
In aquaponics, the idea is that the plants are nourished by the waste created by the fish, while at the same time, the plants purify the water for the fish, resulting in an uninterrupted loop.
The foundation of this system relies completely on the nitrogen cycle. The bacteria transform ammonia, a waste product produced by the fish, into nitrates. Subsequently, a pump transfers the nitrates-rich water to the grow bed that hosts the plants. The plants extract the nitrogen from the water, which nourishes them and purifies the water, resulting in its suitability to be circulated back into the fish tank.
The process recurs continuously, as the fish nourish the bacteria, the bacteria decompose the fish excrement and nourish the plants, and the plants purify the water for the fish to inhabit. It is straightforward!
Why Grow Food This Way?
- Aquaponics uses less water than any other gardening—up to one-tenth of the amount used in traditional soil-based gardening.
- Aquaponics requires less time than regular fishkeeping because plants do some of the cleaning work for you.
- Growing with aquaponics is completely organic. You simply can’t use any harsh chemicals, because they will be fatal for the fish.
- Aquaponics grow beds are usually waist high, reducing the strain on your back while you tend to your plants.
- The amount of time needed to grow with aquaponics versus other forms of food gardening is much less.
- Food can be grown anywhere: indoors, outdoors, in greenhouses, even in your bedroom!
- Systems can be adapted to your needs—small enough to feed a couple or large enough to feed a community.
Aquaponics Design: Which System is Best?
There exist various techniques for constructing an aquaponics system. Among them, the most popular three approaches are:
Setting up a Deep Water Culture system.
The raft-based growing method, also called the deep water culture system, entails utilizing a floating foam raft widely employed in massive industrial setups. This approach enables the plant roots to descend into the water and directly absorb nutrients from the channel through which it runs. The water source is acquired from the tank that houses the fish, filtered to eliminate any solid waste prior to use.
Setting up a Nutrient Film Technique System
By utilizing a slim cylindrical tube, such as PVC, that contains perforations on the top, water is removed from the fish tank. The roots are then placed through the holes to absorb nutrients from the water. This arrangement is ideal for constrained spaces since it can be installed on walls or suspended from overhead. As it can be arranged in either a vertical or horizontal orientation, it is particularly advantageous for crops that do not need additional structural support during growth, such as greens with leaves.
Setting up a media bed.
A particular medium, like clay pebbles, is utilized to cultivate plants in this setup, where the media bed is positioned either above or beside the fish tank. The water from the tank is pumped and filtered by passing through the media bed, which permits the plants to acquire the nutrients. Afterwards, the water is directed back to the fish tank.
In this article, we’ll be highlighting the technique that is most commonly used by home growers, which also happens to be the easiest.
DIY Aquaponics in Five Easy Steps
Here’s how to set up an aquaponics system that will allow you to grow your own food at home using the media bed system.
Step One: Put Your Fish Tank Together
Similar to maintaining fish, it is imperative that you consider all the precautions of fishkeeping. The size of your tank will depend on the species of fish you choose, as your fish will demand a specific amount of space.
If you select a sufficiently large tank, using a standard acrylic aquarium might suffice or be repurposed. Nevertheless, the majority of individuals opt for using opaque-sided food-grade containers or large barrels.
To prepare the tank for your plants, treat the water to remove chlorine and leave it to cycle for roughly 4-6 weeks before introducing any fish. This will allow ample time for bacteria growth, which is essential for breaking down ammonia and nitrites into nitrates that serve as nutrients for your plants.
Ensure that a pump is included in the system to enable the movement of water from the tank to the grow bed and vice versa.
Step Two: Build Your Media Bed
The media bed has the option of being constructed either adjacent to the fish tank or elevated above it.
The flood table, also referred to as the media bed, will serve as the enclosure for the plants’ growth. It can either be a sturdy plastic tray or a wooden pallet container, and should be placed on a robust stand that can handle its weight.
After setting up the media bed, you must pour your preferred media into it. Clay pebbles are a reliable option as they do not alter the water’s pH level and have high moisture retention capacity. Thus, they are a favored choice for home aquaponics.
At the start, maintain a 1:1 ratio between the fish tank and the grow bed sizes to ensure equal volume.
Step Three: Add the Fish
You can add the fish to your tank after it has cycled correctly.
In an aquaponics system, there are various types of fish that are suitable. Some popular options are:
- Tilapia – the easiest fish to grow, simple to care for, and hardy to disease
- Goldfish – produce a lot of waste, so ideal for this setup
- Koi – They grow large and have a high resale value
- Pacu – for those looking for a fancier fish
- Any ornamental fish (guppies, tetras, mollies, etc.)
There are a handful of options that are not as commonly selected, such as:
- Carp – reproduce well and are easy to grow
- Silver perch – a fast-growing school fish that likes high densities
- Catfish – Don’t have scales so handling needs to be kept to a minimum
- Barramundi – the prince of fish in the aquaponics world
Step Four: Add the Plants
In aquaponics systems, leafy plants generally thrive better. Nevertheless, if there is a sufficient fish population, the cultivation of fruit-bearing plants such as peppers and tomatoes is also possible.
Below is a compilation of plants that are simple to cultivate in your system:
- Basil
- Kale
- Lettuce
- Mint
- Watercress
If you have a well-established setup with a heavily stocked tank, it is possible that you could also successfully cultivate these plants.
- Beans
- Cabbage
- Cauliflower
- Cucumbers
- Squash
- Tomatoes
- Peas
- Peppers
- Strawberries
A head start for your plants can be achieved by planting seedlings. Ensure that their roots are carefully placed in the pebbles, allowing them to reach deep down and absorb necessary nutrients from the water as it flows through.
Step Five: Maintain Your System
It is quite effortless to keep up with this arrangement.
In order to keep your fish healthy, it is important to provide them with a high-quality diet. Although a basic flake food is sufficient, it is also okay to offer them a special treat from time to time. However, it is crucial to avoid introducing any diseases into the tank, which is why we discourage the use of live food for your fish.
Limit the amount of food given to your fish to what they can consume within five minutes, feeding them two to three times a day.
It’s important to regularly check the pH, ammonia, nitrite, and nitrate levels of the tank water, preferably every week or two. The ideal scenario is that ammonia and nitrite levels should be undetectable, while the nitrites should remain low indicating that the plants are functioning well.
Maintaining a neutral pH level between 6.8 – 7.0 is recommended to provide an ideal environment for the fish, plants, and bacteria.
After the initial cycle is complete, aquaponics systems usually require buffering because they will fall below a pH level of 7.0. To elevate the pH, tank owners can use calcium hydroxide and potassium carbonate alternatively in a powdered formulation.
Use your usual gardening methods to take care of the plants and you will notice that there are fewer weeds growing.
How To Build An Aquaponic Pond System
Our outdoor spaces are decreasing in size and becoming more eco-friendly, and as a result, we are requiring a greater amount of functionality from them.
Integrating an aquaponic system to an already existing pond is a hassle-free process that can enhance the aesthetics of your outdoor environment.
Install the system
All that is required to transform a simple backyard pond into an aquaponic system, which can support the growth of both edible fish and greens, is the construction of a raised planter referred to as a grow bed, and the connection of a few pipes.
Gravel is added to the grow bed and then planted before being filled with pond water that is pumped in and drained back into the pond.
The gravel serves as a large biofilter by hosting natural bacteria that decompose water waste, allowing the filtered water to return to the pond.
The bacterial presence in pond water provides the necessary nutrients for the thriving of edible plants.
By selecting edible fish for your pond rather than ornamental ones such as koi, you will not only be able to collect vegetables.
If a pond has a depth greater than 600mm and a volume exceeding 2000L, it is possible to transform it into an aquaponic system that can accommodate consumable fish varieties like silver perch or barramundi.
TIP: Ensure you select fish that are suitable for your local climate.
