Back in the day, when we decided not to follow the aquaponics idea (more about that here), we were left with the infrastructure of our aquaponics experiment, which was now freed up to be used for other things. The largest single lump of this infrastructure was the 1000 litre cattle water trough we bought to use as the fish tank part.
The obvious thing to do was to turn it into another productive fish pond/water garden to complement our bath water garden. I had to syphon the water out then with some assistance I was able to turn it through 90⁰ so its long axis faced north, and prepared it for planting
I want to grow some food in it as well as have it there to improve backyard biodiversity and provide a water source for insects and birds etc, too. A friend of mine had offered me some pickerel rush (pontederia cordata), a water plant with edible seeds and young leaf stalks, and I thought this might be a good place to try growing it. Pickerel rush also has attractive blue flowers and I considered that it would improve the look of the backyard as well.
I also wanted to grow some papyrus (Cyperus papyrus) because of its edible starchy rhizomes. It is also present in our constructed wetland, although obviously not edible from this source. For the pickerel rush and papyrus I used a punch to put some holes in large plastic pots, filled them with potting mix, planted what material I had, covered the top of the pots with gravel to keep the plants in and sank them into the water garden.
I did want to grow some water chestnuts (Eleocharis dulcis) and arrowhead (Sagittaria sagittifolia) as well, but these tend to grow around the edges of ponds and so need a shallower area to grow. My pond was 500mm deep so I needed to come up with a new ideas to grow them where I wanted to.
The idea I came up with was to get hold of some wire mesh shelving of the type used in small modular greenhouses, scavenged from the neighbours hard rubbish collection. Then bend them into shelves which would fit over the lip of the pond. I would then to get hold of some 2 litre ice cream containers and make holes in them, fill them with potting mix, add in the required water chestnut and arrowhead tubers and cover them with potting mix, finally adding gravel on top.
I would then install the shelves keeping the ice cream containers about 50mm below the waterline when the pond was full. With everything in place and the pond full, all that was required was a few goldfish to keep the mozzie larvae number down and we were ready to rock.
As winter approaches, the pickerel rush, arrowhead and water chestnuts die back, and I usually cut the dead pickerel rush foliage back. The papyrus stays green and seems to grow happily all year around.
Over the years we have found this to be a pretty and productive space, as well as a delight to watch because of the dragonflies and other flying insects which frequent it.
