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 selected for the aquaponics system should have similar temperature and pH requirements. Indeed, there will always be trade-offs when it comes to the needs of fish and plants. However, the closer they get, the more success there 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 greens, floating “raft” type 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 flowerbeds are a good option. (Endless Food Systems, 2019)
Floating flowerbeds "raft" type
Floating flowerbeds of the “raft” type are suitable for aquaponic systems.
The idea is simple:
- The plant is placed on a floating raft, usually made of large polystyrene sheets. This is where a number of pits are cut to accommodate the roots of the plants.
- Then the roots are immersed in water all the time. Dirt particles must be removed because dirt adheres to the white roots of the plant. This will prevent the plant’s roots from absorbing essential oxygen and minerals that will allow them to mature and grow.
- The advantage of this culture bed is the significant oxygen supply to the roots. That is why the key to the success of a floating raft is to remove the solids and why various filters are needed. (Ecofilms, 2019).
Wick beds are an easy to build vegetable growing system that was developed in Australia. They were mainly closed water reservoirs allowing to water the vegetables from under the root zone of the plant.
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
It is the best solution in a hot and dry environment with a lot of sandy soil where nutrients are easily leached out. Moreover, this culture bed has the advantage of requiring watering only once a week in summer and once a month in winter.
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 about 10-15 cm, root growth and plant activity are most prevalent. During the flood and drain cycle, the drain section allows the water to drain completely. This allows efficient distribution of oxygen-rich air to anything in the area. These include plant roots, soil microbes, good bacteria and composting worms. For the inundation portion of the flooding and drainage cycle, the incoming water helps spread moisture, nutrients, and incoming solid fish waste particles throughout this area. The worms in this area are responsible for decomposing and minimizing 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.
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 is a space-saving, water-efficient way to cultivate and raise fish. It can increase the cultivation space without needing more floor space. In addition, it uses a small fraction of the water needed to grow the soil.
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:
- 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.
- In addition, the oxygen is supplied to the plants through the pipes and directly to the roots as well as through the leaves. The air flows around the tubes because the water does not completely fill the tubes.
The system is basically self-sufficient even if it sometimes requires the addition of a little water from time to time. Unlike a conventional system, a vertical aquaponics system must be equipped 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.
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 is where to place the aquaponics system in the house? If the system is installed in a small room, air must be able to circulate, so be sure to leave the door or window slightly open.
Also, some grow lights produce a lot of heat, so there should be enough space between the plants and the grow lights, especially in small closed 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 year round and the beds are lit.
Create an efficient greenhouse by insulating it to reduce 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 environments, 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. Conventionally, people overcome this problem by warming the greenhouse, but this is an additional annual cost that adds up. In many areas, traditional greenhouses are not used during the winter because heating costs make them prohibitive.