Plants and Aquaponics

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Fish and plants are the main components of the aquaponics system. The growbed media provide the environment for the conversion of the ammonia produced by the fish, into nitrates that the plants need to grow. Your family consumes some of the plants, while some can be used to feed chickens or even back to the fish. The fish produced fertiliser can produce enough food to make a huge reduction in your weekly grocery bill.

So what plants can I grow successfully? The question ‘what doesn’t grow well’ will provide a much shorter list. The only plants in this latter list are those who do not like a pH much above or below a neutral 7.0, such as acid liking blueberries and azaleas, and alkaline preferring plants such as chrysanthemums, calendula, an zinneas.

Root crops will grow very well, but you may not recognise the final shapes, because it finds it difficult to expand in the growbed media.

Apart from these few exceptions, anything that can grown in soil can grow in aquaponics successfully. I am successfully growing rhubarb, strawberries, leeks, beetroot, salad greens, lettuce, cabbage, cauliflower, beans, tomatoes, coriander, parsley, kale, spinach, silver beet and more. I am limited by my seed library and food requirements.

I have broadcast beetroot, salad greens and lettuce seeds and they are successfully growing. I’ve had trouble with bean seeds rotting as they are too wet, so I’ve resorted to germinating on wet paper towel and then transplanting. This also works well for peas, melons and cucumbers. I like them to grow where I want them, not where they germinate, as placement is very important. I put the seeds on wet paper towelling, and place into a ziplock bag, checking them daily. Once the root is about 25mm, I gently plant them into the growbed media, with the root in wetting zone.

I have also bought seedlings and, after carefully washing the seed raising mix from the roots, planted them into the wetting zone of the growbed media.

In the future, I am planning to start seeds in vermiculite or worm castings or even grow plugs to reduce the costs of the plants. Some plants like bamboo and some natives that I grow in soil, can be very successfully started from cuttings inserted into the growbed media. With cuttings, do not use rooting hormones as it can affect the fish in the system.

Aquaponic Rules of Thumb

  • Avoid plants that prefer acidic or alkaline soil conditions.
  • Plants for aquaponics can be started in the same way for soil based gardening.

If the plants are looking unhealthy after a few months:

  • check your pH balance
  • insects
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