An Aquaponics Open Home

People living sustainably all over Australia obligingly opened their homes to the public on Sunday 12th September for Sustainable House Day.

Wendy & Len and their aquaponics system

Len and Wendy from 35 Sperring Street in Manunda, Cairns are passionate about growing their own organic nutritious food, thereby cutting out ‘food miles’ and having easy access to fresh organic produce.

Len in front of his 3 fish tanks

They grow about 60% of their food on their small 1/4 acre residential property using the technique of Aquaponics; breeding freshwater fish for eating in tanks and cycling and filtering the water through grow beds to utilise the fish excrement as a precious plant fertliser.

Using mostly recycled materials, Len has built this self-sustaining aquaponics system himself, and over the last 14 months has put around 60 Barramundi on the dinner table.

110 Jade Perch

In the shade and coolness of his converted garden shed, Len is fattening 150 fish, 110 of which are Jade Perch and 40 Barramundi. He feeds them a main of pellets with a side salad of fresh duckweed and azolla and for desert- worms and soldier fly larvae from his worm farm and compost.

The water and fish nutrients are cycled through the grow beds

Quincan, a volcanic substrate perfect for aquaponics and sourced locally

The water and waste from the bottom of the fish tanks is gravity fed to the nearby grow beds that are filled with quincan a local volcanic substrate that allows for free drainage and supplements the lush healthy looking veggies with trace elements. The grow beds work on a flood and drain system using a bell siphon. The water and fish nutrients enter the grow beds and is circulated amongst the plant roots. Once the water reaches a certain level it is drained down the bell siphon and pumped back into the fish tanks. The whole process of feeding and filling the beds takes 30 minutes and there is a minimal loss of water through evaporation.

A granadilla vine climbing out of the aquaponics grow beds

The imagination is not limited when it comes to what plants you can grow in an Aquaponics system. Some of the more interesting plants in the grow beds were Papaya, elephant ear which has edible leaves, watercress in its’ element and a large climbing granadilla. Very importantly they are grown organically without the use of chemical fertilisers, pesticides or fungicides as they would kill the fish! If a caterpillar or insect is spotted chomping on a leaf it is picked off and fed to the fish. If there is sign of fungal disease or any other pests, homemade organic preparations of milk, basil, garlic, chilli and molasses are used.

Aquaponics is an efficient sustainable food growing system and can be set up in the smallest of urban spaces. The hard work is in the initial setup but once it is up and running it is self sustaining with minimum input from you just a bit of maintenance and fish feeding.

If you have any questions about aquaponics please ask on the For Greenies Forum under the Aquaponics section.

2 Responses

  • julie
    July 30, 2011 at 3:49 pm

    do you have some recipes for jade perch and silver perch, we have an aqua ponics system as well. Thanks julie.

  • Bay
    March 14, 2011 at 1:57 pm

    This is great. By the way, do you need to filter the water from the fish tank before passing it through the plant substrate? Thank you and all my best.

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