As part of our garden project we are building an aquaponics system to grow fresh food in a self-contained soil-less system. Aquaponics is a combination of aquaculture and hydroponics where the waste products produced by the fish in a tank are converted by bacteria into nutrients that plants grown in soil-less beds can use. We hope to raise rainbow trout and barramundi within our system dependant on the time of the year.The Plan
A plan was drawn up in late 2008 by Mr Burns and based on this plan the school purchased a 5000 litre fish tank, 6 grow beds, a sump and two pumps.
The plan includes a decking walkway that covers all the pipework and doubles as a viewing platform for the smaller children within the school.
photo to come photo to come photo to come thumbnail of plan thumbnail of plan drown by students February, 2009
Hardwood timber was cut to size, planed using hand planes to remove sharp edges and drilled with a brace and bit to make benches for our grow bed.
These will be bolted onto four limestone blocks to raise them further off the ground and allow the water from within the beds to drain into the sump via gravity.
The timber was coated with a sealer to help protect it from the elements and some more timber was cut to size for use as a support posts for the tank lid.
thumbnail of planing timber thumbnails of drilling holes thumbnail of trial fitted bench with grow bed students planing Student aquaponics based work Student aquaponics based work
photo to come thumbnail of painting timber thumbnail of painting timber thumbnail of posts The area that was identified for the aquaponics system was grassed area that was not used. The grass was cut using a turf cutter before being rolled upand relayed in an area that needed it. After this a bobcat came in and removed some more soil and levelled the whole area ready for us to start construction.
thumbnail of rolling up cut grass thumbnail of rolling up cut grass thumbnail of relaying grass April,2009
During Kitchen Garden class some of the students dug a hole for the sump to go into before the deck could be built After that Mr Burns' Math group attached the decking stirrups to the bearers that support the decking before moving it into place. Once in place we used measuring tapes and spirit levels to make sure it was in the right spot and level.
Then Mr Burns and some parents poured concrete into the holes around the stirrups. After the deck frame was all in place the pipework for the system had to be made up and attached to the frame before some year 6 students layed the decking with Mr Burns.
As soon as the decking was secure some of the grow beds were put into place over the holiday period, the tanks were filled and the pumps turned on so that the water could start to cycle in readiness for the fish. 14 Koi were added to the sump to help with getting the sytem ready for the 100 trout that were due on the 1st of May. Seeds and some seedlings were planted into the grow beds so they would be growing when the trout arive.
Students putting down decking Measuring space between the bearers Putting down the decking May,2009
Once we arrived back at school after the holidays we helped commission some more grow beds and planted more seeds into them before our trout arrived at the end of the first week. During Kitchen Garden Class we have been putting the final touches on the system, planting more seeds and testing the water quality. Each day we feed the trout at recess and lunch as well as during Kitchen Garden Class. Feeding is enjoyed by students across the school as the trout are very lively and jump up out of the water flashing their colourful rainbow colouring. Our koi are much more quiet and don't usually feed while people are watching.
In all we will have six grow beds filled with three different grow medias, expanded clay, crushed rock (blue metal) and washed gravel. This means we will be able to undertake science experiments to see whether there is any difference between the three types.
Overview picture showing grow beds in place close up of seeds sprouting in hydroton Getting there Sprouting seeds Our trout
picture of trout feeding picture of kids filling grow beds with stone Feeding trout Filling grow beds Overview
