Some time ago we posted info on one of the Primary School Integrated Gardens we built using our Earthan Beds and integrating fish to feed the soil in the beds and plants. I have now uploaded a video of the construction photos of that school garden project.
An explanation of how this garden works
We started out by setting out the garden beds and fish tank we build out of aquaplate onsite. Then the digging starts. This garden was a little more labour intensive than I would have liked but we now have a much simpler way of building these integrated aquaponic gardens.
The general idea of the layout is the centre (green tank) is a 4000 litre fish tank which runs water by gravity from the fish tank to the 12 garden beds. The smaller red rings (6) are about 1.2 m2 and the longer bean shaped cream colour beds (6) are about 6m2 each.
The water runs through the garden beds and gravity back to the fish tank. I know you are wondering how we gravity from a fish tank higher than the garden beds and then gravity feed water back from the lower garden beds to the fish tank…. I will explain that shortly.
The beds themselves are lined and plumbed (all underground) for inlet and outlet water. Then a layer of 20 to 40mm river gravel, a geo-textile fabric over the gravel, a 300mm layer of cardboard form the local supermarket, then a good garden mix soil (Pauls secret herbs and spices lol) and a final layer of good quality mulch. Took some hands and a bit of machinery to get all of that in.
Now it gets a little tricky. The fish tank has a liner inside that green aquaplate ring and it has a sump underwater in the centre. That is how we get to gravity feed. The three large pipes have pipes inside them…. and act as a level control for the tank. They are the outlet by gravity to the garden beds.
The water flows through the garden beds and back to that centre drum (sump) in the middle of the tank which is in the ground a fair way. The sump in the middle is where we pump the water back up into the fish tank and around it goes.
We attach a spray bar for some aeration across the top and connect a 12 volt inline water pump (ready for solar) to get the water moving. Great to stick with 12 volt around water, electrics and children (or adults for that matter).
There are about 200 gold fish to start out. As much as I am not the goldfish biggest fan, the kids love the colours and it gets them interested. We may change out to a native species another day…
A bit of mulch to pack around the fish tank to keep the temperature in the tank stable because the steel can get cold very quickly and heat up as we know from our tin roofs. Put up a gazebo around it with some doors to make it safe and it is ready to grow.
We kept the colours of the beds to match the “decor” of the school so it fits in really well. There are other raised garden beds around the school and this set up consistently out grows all of them. (bit of a plug there lol).
I will endeavour to do a walk through of this school garden as soon as time permits. I hope you have gained some tips for your set up, especially for using soil and reclaimed cardboard for your own integrated garden.