Aquaponics
Growing Aquaponics in a Greenhouse
Aquaponic technology is a self-maintaining food system that merges aquaculture; which cultivates fish, with hydroponics; which grows plants in water. I was able to view the greenhouses at the University of Hawaii and they have a wonderful operation.
Aquatic effluents (liquid waste or sewage) from the fish are discharged into the water with the build up becoming contaminated and eventually lethal for the fish. On the other hand, these effluents are actually nutrients for the plants growing in the same body of water. As the plants feed on the waste, the water is cleansed making it a fresh environment once again for the fish and maintaining water oxygenation.
Freshwater fish like tilapia, silver perch and catfish are the most popular aquatics being cultivated because they are edible and are suitable fish species for home aquaponic systems. Other types of fish like goldfish and koi can be used if there are no plans for personal consumption.
One of the benefits of using an aquaponic system is the ability to recycle the water efficiently. Normally the tank requires only 10% of the amount of water needed to grow plants in soil and a minimal amount of water to cultivate fish. The system succeeds when the aquatic environment is balanced between plant and fish, with little fluctuation in the nutrient and oxygen levels.
The body of water is self- contained and only needs replenishing due to evaporation. The aquaponic system allows the production of both plants and fish in areas where fertile soil is inadequate for farming.
To build your own aquaponic system, use the following steps as a guideline:
- Find a metal shelving unit with adjustable shelves and a 55 gallon fish tank with a water pump
- Place the fish tank at the bottom of the shelving unit. Place a large plastic,shallow container no more than two feet above the tank on one of shelves and secure it with wire. Make sure the container is clean and free from bacteria.
- Fill the plant container with perlite or fine gravel and plant the seeds.
- Add a tube to the fish tank and direct it to the planter above. The water pump will suck up the water from the tank, it will flow through the tube and empty into the plant bed. The plants will use the nutrients from the fish water, oxygenate it and the excess will drain back into the fish tank.
- Add a float valve to the fish tank to ensure the water levels are maintained.
- The greenhouse will provide adequate lighting for the plants.
About the Author
Shelley Awad Greenhouse Consultant, Shelley Awad, provides everything you need to know about greenhouses. Whether you are buying a greenhouse or you already own one, you’ll learn tips and tricks on greenhouses and how to grow year-round. Questions always welcome.
