The water garden was a large pottery pond, half filled with soil, with a layer of water on top, and planted out with enough duck potatoes to give us all the crunchy ''almost water chestnuts'' we might want to add to stir-fried veg or to give texture to noodle dishes. The pond also grew watercress and a few flag irises for beauty.

It survived drying out in the '90s droughts - as soon as the pond filled up again the duck potatoes came to life, as did the watercress. It did not, however, survive an inquisitive wombat who climbed into the pond at 2am, thus tipping it over and breaking one side of it. She and her friends then munched their way through the duck potatoes, tramped the watercress, and all that was left when we came out the next morning was a mess.

Assuming you don't have a wombat, or if you do she is not a rampaging doormat muncher and water garden destroyer, then edible water gardens are fun, productive and far easier to grow than anyone who hasn't got one suspects.

First, find your waterproof container. An old bath or sink works well, or whatever garden ornament you decide to acquire, small or large. You can also plant out the edges of a dam, or dig a pond and use a waterproof lining.

In frost-free areas you can grow water chestnuts. In our climate, go for duck potatoes. They are very similar - small, edible, creamy tubers - but duck potatoes do need to be boiled for 20 minutes before adding to whatever dish you want them to adorn, or sliced thinly as a salad. Don't eat them raw.

Place your new water garden in a sunny spot - a paved courtyard is ideal as it will stay warmer longer over winter. Half fill the container with soil or homemade compost. Plant the tubers 5cm deep in the soil and 10cm apart then slowly and gently add water till there's about 10cm of water over the soil.

The tubers will shoot, then grow arrow-shaped leaves which are quite pretty. The now greatly multiplied tubers are ready to harvest when the stems turn yellow and begin to die back, but you can ''bandicoot'' a few before that. Leave enough tubers for more to grow when the weather warms up again. If you are growing pond crops year after year, the easiest way to feed them is to use home-made compost as a growing medium, or buy commercial aquatic plant food.

There are many other water garden edibles, like fast-growing watercress - germinate the seeds in a pot and transplant carefully - or the sacred lotus (Nelumbo nucifera) that blooms beautifully. Young leaves can be a steamed veg, and the tubers used in a stir-fry. I've never grown or used them, so have no idea how easy they are to cultivate, but as wild ones grow without human intervention, they are probably hard to kill, though our climate may be too cold for them, unless you have a particularly sunny warm spot to keep them safe.

Nor have I grown pickerel rush (Pontederia cordata) whose edible seeds are said to taste like puffed brown rice. (I have never eaten puffed brown rice either). I would have loved to grow water celery (Oenanthe javanica), a perennial bog plant that tastes strongly of celery, and makes delicious water celery and potato soup. Water celery is far easier to grow than celery - all too easy to grow. It tolerates full sun or dappled shade, multiplies fast, and can escape and become a weed, which we couldn't risk with the creek nearby. But as a backyard front yard or courtyard plant in Canberra it should be okay, assuming you aren't near one of the lakes or a stream. Keep an eye out though in case your water celery decides to invade the entire south-east region.

Whole books have been written about water edibles; many dams dug simply to grow them. The beauty of water gardens is that they are, well, beautiful. They also don't need digging, weeding, mulching or much work at all beyond keeping up the water level.

They also definitely do not need a stroppy, inquisitive but still deeply adored wombat.