The demand for “clean” food, internationally, is reportedly growing faster than any other segment in the food industry. Environmentally sensitive forms of agriculture are being restricted in Australia by, amongst other factors, the availability of cost-effective inputs for growers and understanding of alternative vegetable production techniques.

Australian vegetable growers have been very slow to experiment with biological (organic) farming systems when compared to the proportion of land converted to organic growing methods in some European countries and the USA. Farmers in these countries are responding to the consumer demand for “clean” food and/or encouragement from governments to convert land to certified organic farming methods. This is important for Australian vegetable growers, as we need to be aware of tends in our major export markets and how to produce vegetables to new standards.

Compost-tea (compost water extracts) is one exciting natural development that has been used in Europe and the USA for many years as foliar and soil sprays to effectively prevent or reduce the incidence of fungal disease in horticultural crops. The use of compost-tea has the potential to provide a cost-effective disease suppression program in vegetable (and other) crops that is both environmentally friendly and improves farm worker safety.

This project has demonstrated practical methods for producing compost-tea on farms, which is both simple and effective. Effectiveness was measure in terms of total number of aerobic bacteria per ml, in combination with a low human pathogen level in the finished compost-tea. The main limitation of farm-based production is monitoring and ensuring compost-tea quality and resulting effectiveness.

During the course of this work it became obvious that there is a lack of local information on how to grow “clean” vegetable crops in Australia. There is a need for government and grower associations to support growers in producing “clean” vegetable crops.

This project has raised several issues that need to be satisfied if Australia’s vegetable growers are to participate in the growing demand for “clean” food. Specifically these can be summarised as:

• Testing biological disease suppression systems based on using compost-tea on vegetable crops in the field
• Reviewing the packaging, storage, and transport issues the ensure the viability of compost-tea from production to farm use
• Explore ways to encourage growers to adopt biological farming techniques for the production of “clean” vegetables.

This project has been funded by Hort Innovation, using the research and development levies listed below and contributions from the Australian Government. Hort Innovation is the grower-owned, not-for-profit research and development corporation for Australian horticulture.

• Vegetable Fund