Aquaponics symbiotically combines hydroponics and aquaculture. Hydroponics is the cultivation of plants in nutrient-rich water without soil. Aquaculture is the farming of aquatic animals such as fish, prawns and snails in tanks.
Aquaponics is an alternative farming method for areas where protein-rich foods such as fish are scarce or poor soil quality is a problem. In this closed-loop system of farming, fish waste and ammonia excreted by the fish through their gills into the water gets pumped up to the grow bed. Here bacteria (Nitrosomonas, then Nitrobacter) oxidise ammonia into nitrite and finally into nitrate. Nitrate is an essential nutrient absorbed by the plant roots to assist with growth. We then siphon the cleaned water back into the fish tank.
Aquatic Animals
This method of farming cultivates both fresh and saltwater aquatic animals. Saltwater animals include prawns, oysters, sea urchins and pufferfish. Freshwater systems can grow carp, catfish, bass, trout, tilapia and perch. We grow koi and goldfish when the fish in the system are not for consumption.
Grow bed and Plants Cultivated
There are various growing mediums used in aquaponic systems including coco peat, sands, expanded shales, clay pebbles, rockwool and non-carbonated stones.
Saltwater aquaponics systems can grow various plants including seaweed, rice, barley and swiss chard.
The plants grown in freshwater systems include a large variety of: –
•vegetables – leaf greens, okra, tomatoes, squash, peppers and beans
•fruits – strawberries, melons and bananas
•herbs – mint, basil, parsley and sage
•flowers – roses, chrysanthemum and violas
Aquaponic systems are not limited to the varieties of plants listed above.
Benefits
This method of farming is sustainable, enables faster plant growth and uses 90% less water than traditional soil media farming. Additionally, it does not require labour intensive weeding and it allows year-round growing. Aquaponics does not require pesticides or chemicals. We control disease and pests via physical barriers and biological controls.
Drawbacks
It is important to note that a continuous and reliable supply of power and a backup generator is imperative to keep the pumps going to avoid massive loss of aquatic animals. Aquaponics is not a simple and easy system to monitor or manage. Light, air, nutrient, temperature and pH levels are all variables that must be closely monitored and adjusted.
In short, aquaponics is a very useful source of year-round edible plants and aquatic protein especially for places where water is scarce for farming or the soil quality is poor and there is low aquatic protein supply.
