The fish and plant growing system aquaponics makes it possible to grow food at home. If you lower the price for the work, then growing food at home is not economically viable, because the system requires regular maintenance.
How would it sound to raise your own rainbow trout at home? It would be possible with the help of the rotational cultivation system, which has already been used in food production in the ancient Aztec Empire.
Aquaponics refers to a system where a pump transports the water in the aquarium through a biofilter to the plants that utilize the excrement of the fish. The water cleaned of nutrients is transferred back to be used by the fish.
There are completely ready-made circular growing systems for consumers, but it is also possible to build aquaponics yourself. However, rotational farming requires a lot of maintenance. Because of the hours of work involved, growing fish and vegetables using aquaponics at home is not economically viable.
Instead, it’s a fun hobby that allows you to produce local food and observe the ecosystem up close.
Food for a larger group?
– In that case, the small group should carefully calculate the return according to the annual fish catch, because it can be more difficult to earn a profit from salads and vegetables.
However, if you optimize the equipment for vegetables instead of fish, more profit can be accumulated from vegetables, adds Pulkkinen.
– If, for example, fish costs €15–20/kg in the store and the device produces 5–10 kg of vegetables at the same rate, then at current prices, cucumber and tomato are placed in the \”same box\” with fish.
However, with a small amount of feed, you can get a lot of food for the whole group. For example, one kilogram of feed produces one kilogram of fish and up to ten kilograms of vegetables, reveals Pulkkinen.
An environmental permit is not needed right away
Legislation does not set obstacles for small-scale fish farming with an aquaponics system.
– You could grow up to 2,000 kilos of fish a year without an environmental permit. Catches larger than this already require a permit, explains Pulkkinen.
The need for an environmental permit would hardly be a problem for a small group wanting food from aquaponics. The housing company might more likely want to produce a few tens or hundreds of kilos of fish a year, Pulkkinen thinks.
It would be particularly important to pay attention to where the water would be brought into the selected system and where the exit water would end up, reminds Pulkkinen.
Self-grown crabs for lunch
Aquaponics systems can be found for many purposes. In simplified terms, it is a combined aquarium and plant growth medium with LED lighting.
The Internet is full of different systems and they make it easy to start a home hobby. If it’s handy, you can tinker with the system yourself.
– The system makes it possible to produce a wide variety of food at home. In the aquarium, you can grow freshwater aquatic organisms, i.e. fish, crabs and even mussels. In addition to useful plants, various decorative plants can be grown in the growing medium, says Kotiranta.
A mussel transported from one’s own living room to the kitchen has a significantly smaller ecological footprint than comparisons imported from abroad.
What if you built aquaponics yourself?
The price of an aquaponics system depends a lot on what kind of materials the system is made of. Kotiranta has even made calculations for the home version of aquaponics.
– If you build a 500-liter fish tank, and a 2 m² growing area for plants, the material costs are 1,000–2,500 euros.
The initial investments also require fry and seedlings. These costs a total of one hundred euros. Feed for the fish would cost 50 euros a year.
On the other hand, plants do not need to be given nutrients. On the other hand, biological pest control and water conditioners tax the wallet by more than a hundred euros. Water costs about 10 euros per year.
It is recommended to reserve 50 euros annually for spare parts. The electricity bill would be on top of that, Kotiranta lists.
– In the first year, the harvest is mainly from vegetables because, for example, rainbow trout are edible size only after a year.
A 500-liter system could yield 10–15 kilos of fish annually.
– If you compare it to the cheapest food products available in stores, aquaponics food is not cheap, says Kotiranta.
According to him, the value of the system is that you get home-grown food. It also improves the understanding of how ecosystems work.
Fish and plants need constant care
Although maintaining aquaponics at home may sound easy, it requires constant supervision. The acidity of the water and different amounts of nutrients should be monitored.
There are three different groups of organisms in the system, each of which has its own needs related to water quality. For the ecosystem to function, the needs of these groups must be taken into account, says Lukesta Pulkkinen.
– There has to be a balance between the optimal conditions for fish, plants and bacteria on the gravel bed so that everyone can do well enough.
For example, fish create various compounds in the water, which plants may not have time to consume. Then, for example, too much metal or nitrate can accumulate in the aquarium water, says Pulkkinen.
In order to prevent accumulations, the different concentrations of the water must be monitored and, if necessary, the water must be diluted so that the fish can survive there.
Aquaponics expert Jaakko Kotiranta reminds that, if necessary, micronutrients can be added to the plants so that their growth would be optimal. The crop must also be harvested regularly, so that new growth is created.
When properly maintained, aquaponics will produce crops and fish year after year after the first year’s start-up phase.