Home-grown vegetables in a self-sufficient system? Aquaponics!

Read time: 5 mins

Have you ever wanted to grow vegetables/herbs in your home without needing to add fertilizers? Then the answer is aquaponics! I discovered this cool little set-up while having a coffee in my local organic co-op. Being a lover of both plants and fish, I was immediately drawn to the fish tank situated under a vegetable bed in the corner of this quaint café . After inquiring with the shopowner, he informed me it was an aquaponics set-up. Immediately smitten, the DIY-er in me jumped for joy and as soon as returning home I started researching everything on how to begin my own.

So what is it?

Aquaponics is a marriage between aquaculture and hydroponics. Aquaculture is the raising of fish in operations called fish farms, wherein fish are reared in large containers, ponds, or tanks. Hydroponics involves growing plants without soil. Alternatively, plants are grown in a nutrient solution in a growing bed with an artificial medium to keep the roots in place.

Separately, aquaculture and hydroponics have some negative aspects. For example, in aquaculture, excess nutrients need to be continuously removed and replaced with fresh clean water. Additionally, ammonia from leftover fish food as well as waste quickly rise to deadly levels in closed fish tanks and need to be closely monitored. Furthermore, in hydroponic systems, large amounts of nutrients need to be added to the medium in order to ensure plant growth. However, when used in combination these negative aspects are largely cancelled out. In aquaponics, reduced water and nutrients are needed to produce plants. More importantly, crops can be grown in places where agriculture would normally be limited or nearly impossible.

Overall, the idea of aquaponics is to create a system that is as self-sustaining as possible while cutting out the need for additional fertilizers. Plants grown in the vegetable bed essentially receive nutrients from the wastewater in the fish tank and in turn biofiltrate the water for the fish. The goal of this method is to integrate production systems and cut out the need for additional chemicals. Since this system is also nearly self-sufficient, it can be set-up anywhere and minimal maintenance is needed.

 

How do I set one up?

The set-up is simple and requires materials you can easily find at your local hardware store!

You’ll need:

  • Fish tank (3-20 gallon), glass or plastic

  • Gravel (2.5 lbs/5 gallons)

  • Water pump (3-4 watt pump cabale of lifting 18”-54” at 30-100/gal/hour)

  • Air stone (1”-3”)

  • Air pump (sized for number of gallons of fish tank)

  • Plastic tubing (3 ft.)

  • Grow bed (3”-8” deep)

  • Growing medium (Soil, gravel, perlite, etc.)

  • pH test kit

  • Fish and Plants

  • Drill with ¼” or 3/16” bit and ½” bit

  • Shelving

  • Electrical tape

To begin, rinse the gravel thoroughly in a bucket to get rid of any residue and cover the bottom of the tank. Next, drill 1/8” or 3/16” holes in the bottom of the grow bed every 2 square inches for water to drain into the tank. Drill a single 1/2” hole for the tubing of the water pump to pass through on one side of the growing bed. Then, place the water pump in the fish tank and set the grow bed on top of your tank (or use a shelving unit). Feed the tube through the 1/2” hole in the growing bed leaving enough tubing to extend 3/4” of the height of the bed. Loop this extra length of tubing around the inside of the growing bed, cut off any excess tubing and seal it with electrical tape. The next step is to put growing medium in the growing bed to just under the top of the tube. Punch holes every 2” in the tubing that loops around the growing bed and cover it with another 1-2” of growing medium.

Next on to the tank! Fill the dish tank with water, set up the water pump, and test the flow of water from the grow bed to the tank. Connect the air pump to the set-up with air tubing, place the air stone in the tank, and plug in the air pump. It is important to check the pH of the tank, as fish are very sensitive to changes. The ideal pH of your tank water should be around 7, if too high or low add a pH “up” or “down” product. Before adding fish, allow the water to sit for a full day in order for extra chlorine to dissipate. Stock the tank with fish. Hardy, coldwater species such as goldfish, guppies, and angelfish are among the best choices. As a rule of thumb, you should have no more than 1/2" of fish per gallon of water. Finally wait approximately four weeks before adding plants to the system as this allows adequate nutrient build-up in the growing medium.

Et voila! Now you can raise vegetables and herbs while enjoying the sight of your new fishy friends. Minimal maintenance and no fertilizer needed

 

REFERENCES:

Blidariu F and Grozea A. 2011. Increasing the Economical Efficiency and Sustainability of Indoor Fish Farming by Means of Aquaponics. Animal Science and Biotechnologies, 44(2):1-8.

Graber A and Junge R. 2009. Aquaponics Systems: Nutrient recycling from fish wastewater by vegetable production. Desalination, 246:147-156.

 

 

 

 

 

 

 

 

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