Aquaponics farms are installations of different sizes that host aquaponics systems. This means the fish tanks and the cultivation beds where the chosen plants to grow.
The largest aquaponics farms currently available can include floors with a vertical aquaponics system that can be adapted according to the plant to be cultivated.
Plants and aquaponics
The fish and plants chosen for the aquaponics system must have similar requirements in terms of temperature and pH. In fact, there will always be compromises when it comes to the needs of fish and plants. However, the closer they are, the more successful it will be.
Some plants are suitable for any aquaponics system and are easy to grow. These include kale, Swiss chard, arugula, basil, watercress and chives. Others, however, have higher nutritional requirements and only work well in a well-established and densely populated aquaponics system. This is the case for tomatoes, peppers, cucumbers, squash, broccoli, cauliflower and cabbage. (Aquaponics, 2019)
Choosing the right culture bed
There are different cultivation beds including floating flowerbeds of the “raft” type, wick beds or media beds.
For plants such as lettuce, herbs or leafy vegetables, floating raft beds are ideal. For root vegetables, wick beds are a better choice. To grow tomatoes, peppers, beans, strawberries or most other types of multi-yielding plants, media beds are a good option. (Endless Food Systems, 2019)
Floating flowerbeds "raft" type
Floating “raft” beds are suitable for aquaponic systems.
The idea is simple:
- The plant is placed on a floating raft, usually made from large sheets of polystyrene. This is where a number of holes are cut to accommodate the plant’s roots.
- The roots are then immersed in water at all times. Dirt particles need to be removed, because dirt sticks to the plant’s white roots. This will prevent the plant’s roots from absorbing the essential oxygen and minerals they need to mature and grow.
- The advantage of this culture bed is the important oxygen supply to the roots. This is why the removal of solids is key to the success of a floating raft and why various filters are needed. (Ecofilms, 2019).
Wick beds
Wick beds are an easy-to-build vegetable growing system developed in Australia. They were essentially closed water tanks that allowed vegetables to be watered from underneath the plant’s root zone.
This is the best way to grow roots. Wick beds are not only for root crops. Effectively, they allow to grow any plant, edible or decorative, fruit trees or vegetables.
This system is fed with nutrient-rich fish water from your aquaponics system:
- Fish water is fed once a week in summer through a slotted pipe
- This allows the water to flow downwards and to “move” slowly upwards by capillary action
- And thus will allow to feed the roots of the plants from the bottom to the top
This is an ideal solution in a hot, dry environment with a lot of sandy soil, where nutrients are easily leached out. In addition, this cultivation bed has the advantage of only needing to be watered once a week in high summer and once a month in winter.
Plates-bandes médiatiques
In media beds, there are three aquaponic growing bed zones, and each zone has a different purpose and responsibilities.
The standard generally accepted for the width of a cultivation bed is 30 cm deep. This being said, some aquaponic gardeners use shallower or deeper beds. This allows the system to be more robust since the bench rarely needs to be cleaned because the depth allows for more efficient decomposition of solid waste.
Aquaponic culture bed
- The surface zone or dry zone: the light penetration zone and the dry zone are located in the first 5 centimeters of the culture bed. This dry zone reduces evaporation and prevents crown rot in the base of the plant. Keeping this area dry can also prevent the formation of algae on the surface of the medium. This will reduce humidity-related plant diseases such as powdery mildew.
- The root zone: in this second zone of around 10-15 cm, root growth and plant activity are most widespread. During the flooding and emptying cycle, the emptying part allows the water to drain completely. This allows oxygen-rich air to be distributed efficiently to everything in the area. These include plant roots, soil microbes, good bacteria and composting worms. For the flooding part of the flooding and drainage cycle, incoming water helps to spread moisture, nutrients and solid fish waste particles throughout the area. The worms in this zone are responsible for decomposing and minimising the solids, which in turn release nutrients and minerals into the system.
- Solids collection and mineralization zone: in this last zone representing the last 5 centimeters of the culture bed, solid fish waste and worm castings are collected. It is important to take into account the width of the bed, as the bed will need to be accessible from one or both sides in order to deal with it. The important thing is to have access to all areas of the crop bed.
Vertical aquaponics
What is it for?
Vertical aquaponics simply refers to an aquaponics system that rises to the top. This system grows vegetables without soil in columns above an aquarium.
It’s a water-saving, space-saving way of gardening and raising fish. It can increase growing space without the need for more floor space. What’s more, it uses a small fraction of the water needed for soil cultivation.
A true vertical system will focus on growing as many plants as possible on top of each other.
The key to a successful vertical aquaponics system is to make sure there is enough space for each plant to grow and have enough light. And all of this by minimizing the spacing between plants. The advantage of vertical structures is that the plants grow efficiently on top of each other. This allows a single vertical aquaponics tower 1.5 meters high to support the same number of plants as a hydroponic system that occupies 3 meters by 1.5 meters but only operates on one level.
The vertical platforms grow the majority of the culinary herbs in the system:
- thymus
- basilic
- aneth
- cilantro
- parsley
- salvia
- stevia
- rosemary
- mint
- lots of standard greens
Principle of this aquaponics
The principle is based on the use of tubes to create many small pockets where plants can grow.
- A pump takes the water, full of nutrients, and drops it into the top of the cylindrical tubes that form the vertical aquaponic towers.
- The water slides inside the aquaponics pipes and gives the plants the nutrients they need as in traditional aquaponics.
- What’s more, air circulates through the pipes, supplying the plants with the oxygen they need directly to the roots and through the leaves. The air circulates around the tubes because the water does not completely fill the tubes.
The system is basically self-sufficient, although it does require a little water to be added from time to time. Unlike a conventional system, a vertical aquaponics system must be fitted with a filter.
This filter should be placed before the water is supplied to the plants to prevent waste from attaching to the plant roots.
Indoor aquaponics
One of the advantages of aquaponics is its versatility. That is to say, it is possible to adjust an aquaponics system as needed. If there is not enough space in the garden or no garden at all, aquaponics also allows you to grow vegetables indoors.
Since this system is flexible, it can be installed in any room of the house or in the garage.
The most important things to be considered when growing vegetables indoors are:
- Space: This is the main problem, especially when you live in a small apartment. However, an aquaponics aquarium system in a closet-style environment is ideal for gardening in city apartments because they are small, decorative and portable.
- Location: The question to ask is: where should the aquaponics system be placed in the house? If the system is installed in a small room, air must be able to circulate, so make sure you leave the door or window slightly open.
What’s more, some grow lights produce a lot of heat, so there needs to be enough space between the plants and the grow lights, especially in small, enclosed rooms. - Lighting: There will probably not be enough lighting for the windows inside. This lighting should therefore be completed with grow lights (or used entirely). Attention, the blue and red spectrum that plants absorb must be covered.
Indoor aquaponics lighting
The following lighting can be used for indoor aquaponics:
- T5 fluorescent lamps: they are low power consumers and produce little heat. However, they are not very flexible because they only reach 45 cm of the canopy. In addition, their performance decreases significantly after six months, so the bulbs must be replaced.
- High Intensity Discharge (HID) lamps: these are for the serious indoor grower and are divided into five different parts. The light produced is very efficient and the lamps can last for about a year. The disadvantage of these lamps is their high cost and high energy consumption.
- Light Emitting Diode (LED) lamps: This is one of the newest lighting technologies. They do not produce heat and consume a minimum of energy. In fact, these bulbs rarely need to be replaced. LED technology has improved and become affordable in the past few years. However, it is still not as effective as other forms of floodlighting.
Aquaponics under greenhouse
A passive solar greenhouse combined with an aquaponics system can provide efficient food production for the whole year. Passive solar greenhouses can work just about anywhere, but they are particularly well suited to challenging growing environments such as high altitude locations, extreme weather conditions, poor soils or difficult terrain.
Passive solar greenhouses with an insulated north wall and south-facing glazing are ideal for aquaponics systems. The tanks remain more stable in temperature against the north wall, the greenhouse is a warmer environment all year round and the beds are lit.
Creating an energy-efficient greenhouse by insulating it minimises temperature fluctuations. This is especially important in an aquaponic greenhouse, where you want to keep the air temperature and root temperatures stable, but also the fish tanks as well.
In cold climates, the use of hardier fish species such as perch or koi, which do not require hot water, will reduce heating costs. However, the average uninsulated, unheated greenhouse will have the same temperature inside as outside. This means that if it’s 20 degrees outside, it will be 20 degrees inside and you could have dead plants or worse, a frozen block of fish ice. Traditionally, people overcome this problem by heating the greenhouse, but this adds up to extra annual costs. In many regions, traditional greenhouses are not used during the winter because the heating costs make them prohibitive.