The ideal soil conditions for truffle production are friable, free-draining and warm soils. The soil should not be prone to waterlogging, have a variety of particle sizes and a high calcium content.

Truffles grow best on flat to rolling whenua (less than 15° slope), and access to the truffles for harvest needs to be carefully considered.

Truffles need a moderately deep soil of at least 100cm to grow well. Truffles grow on the shallow roots of the host tree and access the mycorrhiza fungi, nutrients, and water they need in the upper soil layers.

Truffle trees generally do best in soils that are low in available minerals and especially in phosphorous. This is because the lack of nutrients in the soil stimulates the symbiosis with the truffle mycorrhiza. This means that the truffle solubilises phosphorous from mineral phosphate in the soil along with other nutrients and provides these nutrients to the tree roots. pH is very important and needs to be in the range of 5.8 - 8.5. For example, the Périgord black truffle (Tuber melanosporum) (Tuber borchii) has a pH requirement of greater than 7.5 with the optimum being 7.9. Bianchetto truffles can grow in a wider pH range of greater than 6 to less than 8.5.

Read more about selecting a suitable location for growing an edible mycorrhizal mushroom.

In Aotearoa, truffles require at least 2000 annual sunshine hours. They need winter temperatures averaging 1-8°C to trigger fruiting, and temperatures within 16 - 22°C during the December - February period for ideal growing conditions.

Truffles need regular rainfall of 800-1500 mm per annum spread over the entire season (if there is no irrigation). Too much rain will lead to rot and too little rain (especially over summer) affects the production of the truffles the following season.

The installation of an irrigation system before planting might be a consideration if your annual rainfall is not consistent across the entire year (less than 700 mm).

If you're thinking about growing truffles on your whenua, check the rainfall and rain intensity in your region. The distribution of rainfall events is very important while your truffles are growing.

See NIWA for more information.

Truffles are not a short-term, quick-return crop, meaning they require a significant amount of planning and a long period of time to establish before any returns are possible.

When planning to plant truffles, you will need to consider your geographic location and the types of truffle-innoculated plants suited to this location. Different varieties of truffles will grow better in the North Island than the South Island due to temperatures. Soil PH levels are also a major influencing factor on which type of plant is best suited. It is highly recommended that you seek professional advice on what types of truffle suit your whenua, talk to NZ Truffles.

NZ Truffles

Truffles are planted in either autumn or spring into well-cultivated ground that has not been over-fertilised.

Truffle inoculated host plant seedings must be ordered in advance from a nursery specialising in this area of horticulture.

You will need to think about your soil pH when you are first planting your host trees (e.g. oak trees). For example, soil pH can be modified using high rates of lime.

Planting density will be influenced by the species of the host tree, the local climate, and your intended pruning and management routine.

Truffle-inoculated host trees will grow for more than 5 years before they may start producing truffles. Once the trees start producing truffles, they can produce for many years. Some trees though may never produce truffles.

Harvesting truffles is done by hand between June and August. A specially trained dog is used to help locate the truffles in the ground. Once the dog has indicated where a truffle is, it is gently removed from the ground by hand. Truffles can be at a depth of up to 30cm underground.

Harvesting should be done at least weekly.

After harvesting the truffles, they must be distributed to the market (either domestic or export) as soon as possible due to their limited shelf-life.

After harvesting your truffles, the storage of your crop is very important. This ensures your crop can get to international and domestic markets in the best possible quality.

A truffle loses weight and aroma every day post-harvest. They should be stored in a chiller almost immediately after they come out of the ground, and shipped to the purchaser as soon as possible to ensure they reach the consumer in the best possible condition.

Truffles can be affected by competition from surrounding incompatible trees for the soil ectomychorrhizal fungi. They can also be troubled by small animals like rabbits eating the young shoots and plants. You will need to consider using pest management methods, such as:

• counting the number and species of pests weekly
• monitoring trees to assess plant health
• removal of competing trees
• targeted use of pest control measures.

New Zealand Truffle Association

The New Zealand Truffle Association is the representative body for New Zealand truffle growers. Members of this group pay a voluntary annual membership fee to fund collective research into market access, and product development and share knowledge.

Several hundred truffle growers are operating across New Zealand, and around 20 sell their products commercially.

New Zealand Truffle Association

New Zealand Truffle Co-operative

Formed in 2022 by the New Zealand Truffle Association, the New Zealand Truffle Co-operative allows the growers to pool their resources. A key objective is to grow the export markets for New Zealand truffles.

New Zealand Truffle Co-operative

Export market

The global demand for truffles exceeds supply due to diminishing annual volumes from traditional European truffle-producing regions. Truffles are a valuable and sought-after culinary delicacy used in high-end restaurants around the world. In 2022, New Zealand truffles were primarily exported to Japan and Australia, where they reached an average value of $1,674/kg. The total export volume in 2022 was 0.023 tonnes, and there is significant potential to grow exports by selling high-quality, New Zealand-produced truffles to counter-seasonal Northern Hemisphere markets.

New Zealand Horticulture Export authority

Scale

Truffles can return a profit from a small or large-scale enterprise. Most New Zealand truffle farms are small to medium-sized plantings of 0.5 to 2 ha. A significant percentage of these have yet to produce truffles. Turning a profit from producing truffles depends on several factors, like:

• your location - access to the market (truffles have a very short shelf-life), or infrastructure
• your production practices
• the market demand and access to the market, as well as truffle export specialists, and the ability to leverage New Zealand’s strong global reputation as a supplier with proven provenance
• your operational efficiencies - larger farms may benefit from economies of scale because they can spread capital and overhead costs over a larger area.

Equipment and infrastructure

Truffles require significant investment in the development of an orchard comprising truffle-inoculated host trees like English Oak, as well as tools and infrastructure, including:

• host trees sourced from specialist nurseries (and truffle inoculum)
• weed matting
• tree guards
• pruning tools
• mower
• tractors and other field machinery
• fencing
• cool store and cold chain system for shipping
• truffle dog
• transport (truffles have a very short shelf life (up to 14 days post-harvest)
• and extensive irrigation systems.

Contractors could be used to provide some of these services if you are farming on a smaller scale.

After harvesting your crop, you'll need to keep them cool and ship them (using a cold chain system) within 48 hours of harvest.

Jobs and people

Professional site analysis is required because getting the right combination of climate, soil, water availability, and topography will make or break your venture. You will need advice from an agronomist specialising in truffle culture.

Your people and labour requirements are seasonal, based on key milestones, like planting and harvesting. The specialists will help you with:

• managing the crop cycle,
• pest management techniques,
• harvesting and,
• post-harvest management.

When truffles are mature (from June), harvest needs to occur on a weekly or bi-weekly basis depending on maturity, productivity, and the size of the farm. Farmers usually work with a dog trained to locate truffles by scent.

Case study - Bay of Plenty truffle farm (truffière)

Here is an example of a truffle farm in the Bay of Plenty, growing intensively managed Perigord truffles, let's imagine it had 10 hectares of truffles grown last year.

It yielded 400 kilograms of truffles, bringing in a revenue of $788,000.

It had $100,000 in expenses, and the farm made a profit of $688,000.

It took 9 years for truffle production to reach 40 kilograms per hectare per year.

Operational costs

Orchard maintenance (pruning and soil maintenance) will be ongoing and estimated to be around $1,200 per hectare per year. Costs for contracting expert advice, and labour involved in the harvesting season varies from $10,000-$30,000 per year according to the size of the orchard and individual circumstances.

Set-up costs per hectare for growing truffles range between $35,000 and $70,000 This depends on factors, like:

• scale of the operation
• inhouse expertise and contracted expertise
• specific farming practices
• regional and locational factors
• market conditions.

After orchard establishment, labour costs will be low. Some other examples of costs that you'll need to consider are:

• fertilisers
• pesticides and herbicides
• permits, licenses, or certifications
• compliance with regulations and food safety standards.

Costs to consider

There are some costs you will need to consider, and these will change with the amount produced. Here are some examples:

Yield (and time to profit)

It takes at least 4 to 5 years for the first truffles to form, approximately 10 to 11 years to reach ‘break-even’ and even longer (12 -14 years) to achieve commercial yields. The volume of truffles produced by individual trees is highly variable. While maximum production of truffles is typically 2-4 kilograms per hectare until year 6, it may increase to 40 kilograms per hectare during years 7-12.

Truffles can offer significant returns from $3000 to $5000 per kilogram.

Here is the pricing schedule for retail sales of truffles from the winter 2023 harvesting season as supplied by the New Zealand Truffle Co-operative:

NZTC Indicative Pricing For 2023 (NZD/g excl GST)

New Zealand Truffle Co-operative

Maximising the amount of good quality truffles produced will increase the profits you earn.

Revenue

Truffle production is an emerging industry in New Zealand and there is scarce data to support a business case. Returns from truffle farming are influenced by a variety of factors, including:

• market conditions
• yield
• quality
• production costs
• pricing strategies
• events beyond your control, for example weather conditions or market fluctuations.

Things we can do to create better returns include:

• efficient practices to maximise yield and production.
• market demand and pricing
• quality and grading
• Cost management
• Storage and post-harvest handling
• Value-added opportunities

To help you make informed decisions and maximise returns, it's important for you to:

• stay informed about market trends through research.
• maintain good relationships with buyers and truffle export specialists
• regularly assess your farm's production and financial performance through tracking costs.

Operating profit

To estimate your operating profit, you'll need to look at the amount of money generated from selling your truffles, minus your production costs. Some factors may affect your revenue and influence your farm's operating profit. These include:

• farm size or the size of your truffle growing area
• yield - the quantity of truffles sold
• market conditions and fluctuations
• production costs and efficient farming practices
• pricing strategies
• weather conditions.

You will need to consider your production costs, which can include:

• labour
• orchard and soil maintenance costs
• fertilisers
• irrigation
• pest and disease management
• machinery maintenance
• storage
• packaging
• marketing costs.

These costs can be affected by having efficient farming practices and effective cost management.

Each farm will have factors specific to them and different market dynamics. Keeping accurate records of your production and financial records can help you see where improvements could be made and increase your operating profit.

Most of the truffles produced in New Zealand are sold domestically. Aotearoa exports very small volumes of truffles to 4 markets including Japan, Australia, the Pacific Islands, and Fiji. The authorities can provide information on what's needed to export truffles, including:

• procedures
• documentation
• fees or licences
• packaging standards
• biosecurity requirements.

To export truffles, you need to follow legislative requirements, including:

• you must be members of the NZ Truffle Association to obtain and retain an export licence. Export licences must be obtained from the Horticultural Export Authority (HEA). The HEA website provides all the relevant information and forms required to obtain an export licence, or to apply for an exemption.
• meeting export requirements, like documentation and packaging standards
• ensuring food is grown so it can be sold under the Food Act 2014
• meeting regulations around risks to freshwater.

Horticultural Export Authority

You must comply with National Programme 1 requirements under the Food Act 2014. This includes:

• following safe food practices, like checking for pests and using clean water
• registering your business with either your local council or MPI
• getting your business verified.

Learn more about National Programme 1.

You will need a freshwater farm plan, either now or by 2025 if your whenua will have:

• 20 hectares or more of arable and/or pastoral use, or
• 5 hectares or more of horticultural use, or
• 20 hectares or more of combined uses.

These plans identify actions to manage and mitigate risks of on-farm activity to freshwater. They must be certified and audited, then recertified every 5 years.

Learn more about freshwater farm plans.

Some additional certifications and registrations may make your truffles more appealing to buyers.

You can choose to get certified with New Zealand Good Agricultural Practice (NZGAP) for a yearly fee. Some retailers and wholesalers only take crops from an NZGAP-certified supply channel.

Learn more about NZGAP.