Hydroponic trials at the University of Technology, Sydney (UTS), are helping to turn two native plants, formerly the preserve of a few gourmet restaurants and specialty food distributors, into fast growing, reliable and consumer-friendly farm crops.

Horticulture researcher Ms Amani Ahmed, from the UTS Department of Environmental Sciences, has just harvested her first trial crop which proved warrigal greens, a leafy spinach-like vegetable, to be a suitable native plant for large scale hydroponic production.

Ms Ahmed says despite the immense popularity of the idea of bush food, it remains peculiarly unknown to the average Australian diet.

"People immediately assume it's witchetty grubs, kangaroo and survival food," she said. "They don't realise the variety of edible plants Australia has to offer."

Ms Ahmed's breakthrough hydroponic technique will help commercial growers produce crops of sufficient quantity and quality to make them a viable, and novel, product option for major supermarket chains.

"We use hydroponics to produce faster growing, grit free crops of a more consistent quality," Ms Ahmed explained." We also have better control of the nutrients and can produce differing qualities of the same plant by varying the nutrient intake. This way we can select the techniques which will be best for commercial cultivation."

"Warrigal greens have compounds in the leaves - oxalate, nitrate and saponin - which prevent them from being eaten fresh, so they have to be blanched in boiling water first," Ms Ahmed said. "What we are trialling is the reduction of oxalate levels in the plants by controlling the nutrient intake."

Ms Ahmed found that in the first trials of the warrigal greens, based on taste qualities, using the hydroponic technique reduced the oxalate levels enough for the warrigal greens to be eaten without blanching.

Bush tomatoes are at present sold in dried and in powdered form and used as flavouring. Ms Ahmed is looking at identifying the best methods for producing commercial plants - both from seed and tissue culture.

"While a germination study is testing the response of seeds to varying conditions, tissue culture trials are aiming to produce a consistent and viable variety of tomato," she said. "We take a sample from a plant which we prefer for its taste and quality and clone it."

Ms Ahmed said other native plant species now are being cultivated, including a coastal plant, (known as "pigface"), with a red fruit described as a "salty strawberry".

"There are thousands of edible Australian plants," Ms Ahmed said. "Native celery, for instance, would be well suited to hydroponic culture. It's a wild form of the celery we eat now, but it has celery flavoured leaves instead of a stalk. Wild celery could be used in salad mixes or as a seasoning. There are also nuts, herbs and spices currently available commercially."