Aquaponics is the combination of 2 systems, hydroponics and aquaculture. Hydroponics is the growing of a plant in a soil-less environment with added nutrients and aquaculture is the raising of fish in a domestic environment. With aquaponics, the nutrients to grow the plants comes from the fish waste which is then recirculated with the water into the grow beds feeding the plant and then giving filtered clean water back to the fish.
The Aquaponics Cycle
Fish excrete ammonia waste in the form of feces, urine and respiration from the gills. Ammonia is toxic to fish and is not available to be taken up by plants, so the ammonia needs to be converted into nitrates for the plants to use. All aquaponics system on startup needs to go through a process called cycling which is allowing for the bacteria to grow in your media. So, fish excrete ammonia into the water and the water is pumped from the fish tank into a grow bed with media, once the cycling process has taken place, the media will contain bacteria which converts the ammonia into nitrites, and convert nitrites into nitrates which is generally harmless to fish and is essential for plant growth.
How do Plants Grow in Aquaponics?
In aquaponics, there are various methods you can use for growing plants, but the most common method is a grow bed filled with media and set up as a flood and drain in which water is pumped into and then siphoned out by an auto-siphon. The plants are planted into the media and the water is then pumped into the grow bed giving the plants the nutrient-rich water which they can uptake. Once the grow bed is full of water the auto-siphon engages removing the water from the bed and returning it to the tank as clean filtered water. The siphoning of water allows the plant’s roots to get oxygen. Plants in a healthy aquaponics system grow a lot faster and generally also produce larger specimens than traditional ground planting methods. Aquaponics systems can come in various sizes and styles, from small indoor systems to large commercial setups.
What Fish can I keep in aquaponics?
There are many different varieties of freshwater fish that can be kept in aquaponics both edible and inedible. Some of the species we have grown are goldfish, koi, rainbow trout and silver perch. Some other species available in Australia are barramundi, jade perch, catfish, Murray cod and sleepy cod.
What Plants can I Grow in Aquaponics?
You can grow any plant you like in aquaponics, some plants that we have found to do very well in aquaponics have been tomatoes, cucumbers, beetroot, broccoli, lettuce, kohlrabi, celery and capsicum.
Why did we choose aquaponics?
Years ago, there was an ad for a thing called Aqauponical which was a small aquarium that had to grow a bed in the top of it. Whilst I never bought one, I liked the idea of it, then for my birthday 3 years ago my wife built me my first aquaponics system which consisted of a 400-litre fish tank with a grow bed on top. We had many struggles with the system and learnt a lot from it but were amazed at how quickly plants did grow in it. After seeing how well plants grew in this system, we decided to build a larger system.
Some of the benefits we have found with aquaponics are the low water use, the plants have a continual water and nutrient source, it’s an organic method and the speed and size in which plants grow to.