Growing Truffles - Australian Truffle Industry Association

Growing Truffles

Growing truffles can be for simple personal pleasure or for profit at a larger scale.
ATIA has a vast range of members, comprising some of Australia’s largest commercial farms down to bespoke or boutique hobby truffières.

Truffles in Australia

Truffles are successfully grown in many regions of Australia providing the critical elements of climate and soil are suitable.

Australia is now the fourth largest producer globally, behind Spain, France, and Italy.

Cultivating truffles is reasonably complex and successful production requires a complete understanding of truffle biology, farm establishment, maintenance, and efficient management.

This knowledge requirement should not be seen as a barrier however, as all necessary skills and processes may be learned over time.

When considering joining the industry, it is important to understand from the outset that truffle production, like many other agricultural crops, requires substantial capital to set up a farm well and is definitely a long-term investment, taking at least 4 to 5 years for first truffles to form, several years (approx. 10 to 11) to reach ‘break even’ and even longer (12 -14 years) to achieve commercial yields.

Truffles

A truffle is the highly aromatic, subterranean, fruit of specialised fungi growing on the roots of specific host trees. Truffle fungi establish a relationship with a host tree, known as a mycorrhizal symbiosis. The fungi live externally on and around fine tree roots and develop a vast network of mycelium in the soil, formed by microscopic filaments called hyphae.

Active mycelium searches for and returns nutrients and enhanced water intake to the tree. In return the tree provides the fungus with sugars and starches from the process of photosynthesis. The fruit body (truffle) is formed when compatible mycelium mating types fuse under the right conditions, and depending on the species, this may occur in spring, summer, and autumn.

The French Black Truffle, Tuber melanosporum, is the most studied and farmed species in Europe, Australia, USA, New Zealand, Chile, South Africa, and other locations around the globe. When fully ripe, the French Black truffle has an intense, pungent aroma and earthy flavour. Its exterior (peridium) is dark and rough, and the interior (gleba) is dark in colour with creamy white veins.

This truffle is endemic to specific parts of Europe generally growing between elevations of 100-1000m (300-3600 feet).

Typical climate zones are Mediterranean, Oceanic and Continental.

Natural habitats are deep, well-draining, stony, calcareous, high pH (7.5-8.3) soils, on warm, exposed sites.

When growing this species in other parts of the world, such as the southern hemisphere, farmers generally need to modify soils, applying what has been learned from scientific studies of natural truffle grounds, field research and the ecology of the truffle.

Site Selection

Site selection is extremely important, involving a complex range of considerations including climate, soil suitability, water resources, topography, large vehicle access and existing vegetation among other things.

Professional site analysis is generally advisable to determine site suitability before investing in a project.

There are specific parameters for the ideal climate range. In general, warm summers and cold winters with preferably, some incidence of frost is preferable. Natural rainfall should be in the range of 600-700mm plus annually.

Rainfall distribution should be reasonably even throughout the year, preferably avoiding very wet winter environments.

A good water supply is essential for irrigations during warmer months. Water must be good quality with relatively low salinity readings. Storage may be a dam or large tanks.

Supply may also be water harvested from infrastructure roofing, a bore or licensed access to a creek or river.

Truffle Soils

Truffle soils need to be extremely friable and well-structured with a broad range of particle sizes. Loamy soils with reasonable even percentages of sand, silt and clay are best. Soils with clay contents higher than 35% are generally not suitable.

The pH of the soil should be in the range of 7.5 – 8.3. This means that most soils in Australian conditions are augmented with substantial amounts of lime and perhaps dolomite in modifying the soil environment for truffle production.

Soil analysis is an essential part of site selection and should be carried out early in the process, as part of ‘proving’ suitability of the site. Samples taken are sent to a laboratory for specific testing.

An agronomist specialising in truffle culture then provides soil adjustment recommendations.

Soil Preparation and Fencing

This may be extensive depending on soil type, compaction issues and recommendations made for pH and structural adjustments.

General treatments include deep ripping to open up compacted soils, spreading and combining of recommended lime, dolomite, and other soil additives. Improved soils are generally left a minimum 9 months for adjustment, prior to planting trees.

Fencing may be required to keep out unwanted animals. Animals grazing the plantation area will damage trees and re-compact soils, therefore fencing must be adequately designed to cope with the prevailing animal issues in the area.

Inoculated Host Trees

Host tree selection decisions will be based on farm management advice and the local environment.

The three main host trees used today for inoculation with French Black truffle are:

French Oak, Holly Oak: Quercus ilex

English Oak: Quercus robur fastigiata (upright species)

European hazelnut: Corylus avellana

It is critical to source the highest quality inoculated host trees produced by specialist nurseries. It doesn’t matter how well you prepare the soil and farm in general, if you don’t start with the highest quality trees, your results may be unreliable.

Industry tree certification programs such as the AVSTEP are based on independent analysis of inoculated trees.

Irrigation

Truffle farms require an extensive irrigation system providing adequate water to each tree when required. Plantations are irrigated through the warmer months, when truffles are developing rapidly, on a semi regular basis.

Moisture monitoring equipment assists in growers determining when irrigations should occur.

Planting Trees

Planting is preferably carried out in autumn in most environments, however, may also be spring, particularly in areas with extremely harsh winters.

Insulated tree guards are installed at the time of planting and used for first 2 years, protecting young trees from small grazing animals, wind, herbicides, and excessive heat.

Young trees are protected from competition and excessive soil moisture evaporation in the first few by the use of weed mat systems.

Research shows that protecting young trees in this way further enhances mycorrhizal development in the soil profile.

Ongoing maintenance required includes annual pruning, pest, disease and weed control as required, summer irrigation, general repairs, and mowing grass inter-rows.

Harvest, Handling and Packaging

Harvest period is Australia begins in mid-June for the French Black Truffle, with truffles gradually ripening throughout the balance of the winter season. Production begins slowly, generally in year 4-5, gradually increasing each year, potentially reaching commercial quantities by year 12-14.

Farmers harvest on a weekly or bi-weekly basis depending on maturity, productivity, and the size of the farm. Farmers systematically search row by row, with dogs trained to locate truffles by scent.

Freshly harvested truffles are placed in refrigeration until processed, ideally within 24 hours. Truffles are washed, dried then inspected for imperfections such as insect damage and bacterial rot.

Grading criteria includes aromatics, shape, size, and extent of any damage if any.

When fully ripe, truffles have a very short shelf life of 12-14 days at best, with an ideal consumption window of 8-10 days. Some aroma and weight is incrementally lost each day once a truffle is removed from the soil.

As aromatics diminish, so may the experience for the consumer, hence ideally, freshly harvested truffles need to be cleaned, graded, packed (in a cold chain system) and posted/delivered to their destination within 48 hours.

Marketing Truffles

People are often attracted to the notion of truffle growing due to the prices per kilo reported by media during the harvest season. Media tend to only report retail pricing which is the highest level.

This retail market is, however, saturated in Australia, as is the wholesale market, which is priced at approximately half the retail price.

New industry entrants should factor in that the bulk of their truffles will need to be sold through truffle export specialists. This pricing represents the lowest return to the grower, however, this market is where the industry will continue to grow.

There are numerous factors to consider when aspiring to grow truffles on a commercial basis, including site suitability, farm establishment costs, current industry sales mechanisms, pricing, and potential return on the investment.

It is imperative to carry out due diligence when assessing the merits of your proposed project. It is advisable to understand all financial, lifestyle and maintenance commitment considerations prior to embarking on farm development.

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