By Guy Ehydro
An Introduction to Aquaponic Gardening
The Aquaponic Method is one of the few true Hydro-Organic options and the best for a gardener interested in balanced ecosystems. You are probably familiar with the concept, having seen rafts of floating lilies or hyacinth living happily on the surface of a pond. In these ponds a balance exists between the fish and plants and that’s what the Aquaponic method mimics.
The fish waste will build up and bacteria breaks the matter down into soluble elements. As this progresses the water becomes increasingly toxic. That’s where the plant’s come in. By consuming the nitrogen and other elements for growth above the surface they filter the water and help keep it healthy for the fish to live in.
The best way to describe Aquaponics is as a symbiotic relationship; the fusion of aquaculture and hydroponics.
The fish produce waste high in nitrogen so nitrogen loving plants such as kale, lettuce, spinach and kitchen herbs are great choices when starting your own aquaponic garden. Fruiting and flowering plants have a much higher nutrient need and more varied requirements as they bloom, so these plants haven’t been found to be the most ideal in these conditions. Building a floating raft for your outdoor pond can be a fun project that adds beauty and value to your outdoor landscape.
Once the seeds or cuttings are selected they should be started in rockwool. Rockwool is a spun molten rock that contains only 5% actual material, the rest is air. It is one of the mediums of choice in food production. Seed starts should be done in a separate propagation tray. After sprouting, wait till the roots are visible on the bottom, then move them into the system. Potted plants can be put in the system as well as long as the roots are rinsed clean of soil and put in expanded clay. Plants should be in pots in Hydrocorn. Plastic pots and fabric pots are great. A pump is crucial for getting the water to the plants. When selecting a water pump, make sure it is large enough to flood the tray quickly. For example, a 396 gallon per hour pump would be suitable for a 2’x4’ tray. A restrictor valve should be placed inline for maximum control. The pump is plugged into a timer to manage the frequency of waterings. A timer will be necessary with young plants, but larger plants maybe able to handle a constant flow of water. This may take some experimentation. There needs to be enough water in the reservoir for it to be able to flood the tray without draining the fishes habitat. But make sure the reservoir is always below the tray. A decent air pump is key for aerating the reservoir primarily because the fish need oxygen to live. When drilling out the tray, make sure the outlets are larger in diameter than the input bulkhead. Hose water is best(tap water that has not gone thru a water softener). RO and distilled water cause problems. Due to their lack of ions, the ph can fluctuate suddenly and kill the fish. A good ph for aquaponics is right around 7. Run the system for a day before adding any fish. Start with one goldfish, if he survives…proceed.
Do not fill the whole tray with medium, it will cause lots of problems. Fish tanks work great as a reservoir. But make sure the reservoir is always below the tray. a ph tester is good to have.
Growing Power in Chicago is a great resource with lots of you tube videos online.
To get started you will need:
- A reservoir – This will be your fish habitat and feeding tank for your plants. Plastic hydroponic reservoirs or fish tanks will work great. . Make sure there is adequate water in the reservoir for it to be able to flood the tray without draining the fishes habitat. Botanicare makes high quality reservoirs that will last for years.
- A flood tray – This is where the plants are watered. Either by a drip line(1/2 inch or larger) or by a pump in the reservoir “flooding” the tray(ebb and flow). The frequency that the plants get watered relates to the size and type off plants in the system.
- A water pump – Be sure to pay attention to the stats on the pump’s box. Every pump has a max fill height and output speed(gph). Small systems can can be operated with lower cost pumps, but larger systems will need magnetic drive pumps.
- An air pump – This will keep the oxygen levels high, in term keeping the fish and the plants happy. A larger air pump can be split up with a manifold or several smaller pumps can be used. Airstones and airline are sold separately.
- Tubing(water/air), fittings, airstones – The fittings you will need are bulkheads, risers and screens.
- Fish – Goldfish work well.