Essential conditions and success factors for truffle cultivation
The truffle is a fungus that is found naturally in various regions of France and Europe. However, the cultivation of this mycorrhizal fungus faces a number of constraints. Several conditions must be met to promote its development :
- geographical location : ideally, the plot should be located on a plateau or have a slight slope. A south, south-east or south-west exposure is recommended to ensure good sunshine. The soil must be sufficiently calcareous, well drained and rich in organic matter..
- climatic conditions are also important, both for the tree and for the truffle. If the seasons should preferably be marked, the climate should not be too harsh (drought, frost...).
- the previous crop (and possible competition from other mycorrhizal fungi) also directly influence the success of a truffle project.
- The quality of the truffle plants
- The quality of the land (the aptitude of the soil for truffle growing, its physical and chemical qualities...)
- The planting method (soil preparation, protection of the plants...)
- The possibility to irrigate the truffle orchard
- The maintenance of the truffle field over time
1. Choosing truffle plants: Rely on the quality of mycorrhizal plants
As a general rule, choose tree species that are already naturally present in your area. Make a list of the hardwoods (or softwoods) already present in the woods and forests near your plots. If the white oak (Quercus pubescens) and the holm oak (Quercus ilex) remain the best truffle trees, other species are also suitable for truffle production: hazelnut, lime, hornbeam, pine, cedar, beech.
After having taken the time to select the species that will acclimatize most easily to your territory, do not neglect the quality of the plants that will make up your truffle farm. Choose plants with certified mycorrhization and produced according to rigorous methods. To increase your chances of success, choose plants with a recovery rate close to 100% (you will save yourself many disappointments a few months after their planting).
Concerning the age and size of the truffle plants, you can choose between young plants of 1, 2 or 3 years old. Just be aware that by opting for plants raised in a larger volume bucket, you optimize the recovery of your trees and their development in the years following planting. Note that a 1 year old seedling raised in a large 0.6l or 1.5l bucket will give the best results.
In the truffle industry, ROBIN® truffle plants are recognized as the best and are the only ones that combine a production method under license and control INRAE + an environmental certification MPS A. The cherry on the cake is that ROBIN truffle plants are guaranteed to recover !
2. Climate and topography favorable to the implantation of a truffle orchard
Geographical location and climate are eminently important factors for the success of a truffle orchard. Even if you have chosen the best truffle plants, if they are planted in an area where the climate is unfavorable to the development of the truffle, understand that your project is in trouble and that your future harvests will be compromised... Before starting truffle growing, it is therefore necessary to make sure that your geographical position (altitude, orientation, topography...) and the associated climate are compatible with the cultivation of at least one variety of truffle.
Ideal climate for truffle growing
Generally speaking, truffle growing requires a temperate climate. It needs a sufficient, but not excessive, alternation of seasons, during which rainfall, temperature and sunshine are well distributed.
Predilection altitude for truffle growing
Depending on local conditions, truffles can grow up to 1000 or 1100 meters, but the vast majority of truffle fields are generally located at lower altitudes, between 200 and 700 meters. Keep in mind that the higher you go, the more factors unfavorable to truffles increase (risk of long periods of frost, higher snowfall...).
Complacent topography of the truffle
Truffles thrive on plateaus and gentle slopes. Avoid shallows, valleys and dolines which are often subject to spring frosts and to important accumulations of water from runoff. These accumulations of water can be detrimental to the development of the truffle.
Perfect exposure of a truffle orchard
For Tuber melanosporum, choose a south, south-east or south-west orientation, as the sunshine must be maximum.
On the other hand, for Tuber uncinatum, the exposure is of little importance since the Burgundy truffle needs more shade.
The synthesis of the above climatic, topographical and geographical characteristics, combined with the nature of the soils, has allowed ROBIN Nurseries to establish a map of the regions of France where truffle cultivation is most opportune.
Map of areas suitable for truffle growing in France
Soil legend :
Click on the map to enlarge it
(Registered ROBIN model map, reproduction prohibited)
3. Evaluate the suitability of your soil for truffle growing
The properties of the soil (physical and chemical qualities) determine its suitability for truffle growing. Its structure, its pH, its organic matter content, its drainage capacity are all characteristics that allow you to confirm if your soil is suitable for the establishment of a truffle orchard. This analysis will guide you on the host species of truffle plants to consider but also on the most promising truffle variety according to the typology of your soil.
The importance of soil analysis
When a plot of land is selected for a future truffle plantation, it is essential to have a soil analysis done. The purpose of this analysis is to determine the species: host (tree) and especially mushrooms best suited to your land. They depend on the physical and chemical characteristics of your land, and in particular its acidity (pH), calcium content and organic matter.
To ensure the best quality production of truffle trees in France, Robin Nurseries will accompany you through a study of your plantation site carried out by the sales manager of your region. We are committed to the success of your truffle orchard. A sample of your soil is taken as soon as he visits you. As the success of a plantation depends on the choice of the soil, these samples for your future truffle orchards are sent to the Teyssier laboratory, our partner specialized in soil analysis. From the results of the soil analysis, the laboratory comments on the possibility or not to cultivate in this soil, a truffle species. ROBIN Nurseries can then advise you on the best choice of host species (oak, hazelnut, hornbeam, lime, pine, etc.) and the most suitable truffle species.
Each truffle has its own favorite soil
The black truffle (Tuber melanosporum) : It requires a calcareous soil, rich in calcium and alkaline reaction. The optimal pH is between 7.5 and 8.5 with at least 8% of total limestone. The favorable soils are generally not very deep, 15 to 40 cm, on cracked rock, of lumpy or sandy structure. They must be well balanced in mineral elements and organic matter: the carbon/nitrogen (C/N) ratio must be close to 10. Avoid compact soils with too much clay texture: 35 to 40% is the limit. The soil must be draining.
The Burgundy truffle (Tuber uncinatum) and the summer truffle (Tuber aestivum) : They require a calcareous soil: pH from 7 to 8. The organic matter content must be balanced. The C/N (carbon/nitrogen) can reach 20. The clay content cannot be much higher than for Tuber melanosporum, up to 40 to 45% maximum.
The white truffle (Tuber magnatum) : From a chemical point of view, the characteristics of Tuber magnatum soils are the same as those of Tuber melanosporum and Tuber uncinatum soils. From the physical point of view, the soils of Tuber magnatum are very particular soils (which explains the geographical location of this species). They are not superficial soils, not stony, with a sandy silty texture, very aerated, with very good drainage, remaining fresh during the driest periods of the year.
Be careful with previous crops
It is known that vine, lavender, alfalfa, sainfoin prepare the truffle field. These plants do not harbor ectomycorrhizal fungi, which considerably limits the potential of competitive mycorrhizae for the truffle. On the other hand, it is not recommended to install a truffle bed on a recent clearing (less than 5 years). The risk of contamination of the young plants by the mycorrhizal strains naturally present on the trees in place is very high, with a decrease in the chances of truffle production. It is also not recommended to plant in the middle of a wood or nearby for the same reasons.
4. Planting truffle orchards: how to proceed ?
Truffle trees generally start producing truffles 5 to 8 years after their planting. Provided, of course, that they are planted correctly and that they are effectively protected against rodents and game, and that they are maintained very regularly.
The ideal preparation consists in working the ground in full, by carrying out a ploughing at 30 cm minimum of depth, followed by a harrowing with a rotary harrow for example. For small plots: less than 2,000m2, the soil should be prepared in pots: the soil should be worked on 2m2 and 30 cm deep in the places planned for planting. If the soil is very stony, make a stone removal of the planting hole, taking care to create a volume of loose soil of about 50 liters around the plant.
Storage and preparation of truffle plants
As soon as you receive the plants, put them in an upright position and water them if necessary. Before planting, store them preferably outside on clean soil (do not store them directly on the ground), protected from frost and wind, and in the light.
Planting of truffle plants
Prepare the ground in advance and open the planting hole. Then remove the plastic envelope of the Robin Anti-Chignon® bucket before installing the rootball vertically without breaking it. Then fill the planting hole with fine soil and cover the top of the root ball with 2 cm of soil. Pack lightly, forming a basin around the plant (to collect water from watering and rain). Finally, water with a minimum of 15 liters of water per plant.
Concerning the distance and the density of plantation, it is necessary to find the good compromise between the precocity and the longevity of the production.
- For Tuber melanosporum : The recommended spacing is 4m on the line and 6m between the lines, i.e. about 400 plants per hectare. It is necessary to orient the lines NORTH ‡ SOUTH so that the sunshine also reaches both sides of the hedge. The planting in square also very interesting must be done by respecting a distance of 5m by 5m between each plant (that is 400 plants per hectare).
- In the case of Tuber uncinatum, densities of 800 plants to 1000 plants / hectare (i.e. 4x3m or 4x2,5m) are frequently adopted, because this last truffle develops preferably in fresh and shaded areas.
- For Tuber aestivum : we will plant at a density of 400 to 500 plants/ha (5x5 to 5x4 m) as for Tuber melanosporum.
- For Tuber magnatum : the distances of plantation are identical to those of Tuber melanosporum, that is 400 plants/ha (4x6m, or 5x5m).
Once your plants are in place, you can mulch them. The use of mulch avoids the tedious chore of weeding at the foot of the plants for the first two years and reduces water evaporation (which helps maintain moisture at the roots of your young plants). There are various types, the most effective are the biodegradable mulching slabs of agglomerated cork (Robin cork slabs of 70 cm in diameter). For all large-scale plantings, 80 micron plastic mulch can be used, to be unrolled in strips. This will simplify maintenance for the future. This mulch should be removed between 3 and 4 years after planting.
Protection of your young truffle plants
The installation of individual protection nets against rodents is essential. To protect the young plants against game, you must choose a climatic mesh protection (or windbreak mesh). In addition to protection against game, it will act as a shade during hot weather and as a windbreak during cold and windy periods that dry out the plants. We recommend you to choose a protection of height H60cm and diameter 20 cm against rabbits or hares, and H120cm and diameter 30 cm against roe deer.
Against wild boars, at the moment, the most effective protection, the least expensive and quickest to install remains the electric fence.
NB : ROBIN TRUFFIERS are guaranteed to recover at 80%, and this guarantee is increased to 100% for plants protected by a windbreak sheath and a ROBIN cork slab type mulch. (See conditions of application in our current catalog).
5. Care of a truffle field : What to do ?
Once your truffle plants have been carefully planted, mulched and protected, it is the continuous maintenance of your truffle field that will determine its evolution. Irrigation, soil work and pruning of the plants are all operations to be repeated regularly throughout the first years of your truffle orchard.
It is essential during the first two years, to ensure the recovery of the plants, with a micro-sprinkler (never with a drip) or manually by bringing 15 liters of water / plant after planting and during periods of drought. To limit watering during the three years following the planting, it is really advised to install a mulch at the foot of the young truffle plants. ROBIN cork tiles are recommended.
- Between the 2nd and 5th year, watering is only necessary in case of drought, and the frequency will be adapted to the climatic conditions and the type of soil.
- From the 5th year on, watering will be aimed at satisfying the water needs of the truffles. It must always be adapted to each type of soil and to the rainfall. On average, it is recommended to water about every 3 weeks.
Keep in mind that a badly conducted irrigation is more harmful than no irrigation.
Soil work is necessary to obtain a quality plantation and an early production. It is essential to start working the soil at the foot of the trees from the first year of planting on 1 to 2 m2 and 15 to 20 cm deep, if no mulch has been laid and from the third or fourth year after removing the mulch.
Tillage creates favorable water conditions and guarantees a supply of organic matter that promotes intense biological activity in the soil. Finally, this work allows the aeration of the soil.
On the other hand, working the soil with a cutting tool also has a very important effect on the root system. By working the soil we also perform a root pruning, and this pruning has the effect of stimulating the growth and development of the root system and thus maintain the development of mycorrhizae which develop essentially on the juvenile roots. Ideally, the soil should be worked manually with a hoe or a pickaxe. In the case of planting on a large surface, mechanical work should be carried out with a griffon, a vibro-cultivator or a harrow over a minimum depth of 15 to 25 cm depending on the depth of the soil. It is advisable to work once a year, at the beginning of spring at the end of March and beginning of April.
Truffle tree pruning
Pruning ensures correct sunlight and stimulation of the root system. The trunk should be cleared to a maximum of 50 to 70 cm to allow for good sunlight. Note that plantations that are not irrigated benefit from not being pruned too much, at the bottom in order to keep a little freshness, thanks to the shading. It is advisable to thin out the inner branches of the crown, when it becomes too dense, in order to limit the risks of diseases and parasites. It is also recommended to prune the branches laterally and in height in order to limit the development of the crown in diameter and thus to favour the sunshine at the foot of the trees.
This type of pruning is only recommended for Tuber melanosporum. And it should be done progressively from the 2nd or 3rd year after planting according to the growth of the truffle plants.
The ascospores that are present in truffles seem to have an important role in the sexual reproduction cycle of truffles. For all species of truffles, a contribution of ascospores or reseeding of the truffle fields can be recommended in order to promote production. On the other hand, it is necessary to use only quality inoculum produced from truffles controlled morphologically and by a second DNA control.
These inoculations can be either in full around the tree, or localized in trenches or in the form of truffle traps.
Make sure to use only contact products. Do not use any systemic products! Against powdery mildew: Bordeaux mixture or sulfur can be used alternately every 15 days between April and June. Contact insecticide only in curative if necessary.
6. The truffle harvest: When and how to proceed ?
The appearance of the "burned areas" can occur from the 3rd or 4th year, and the production can start under the first trees between the 5th and 8th year for Tuber melanosporum, and between 6 and 10 years for Tuber uncinatum. It will depend on the maintenance, the watering and the ground.
Known as "hypogees", truffles develop underground. Their search, called "cavage", is therefore delicate. The nose of a trained dog, or even the observation of specific flies, can help you find them more easily, but the dog remains the surest way to look for truffles.
The harvest period depends on the variety of truffles produced. The Burgundy and white truffles mature in autumn, the black truffle is harvested in winter, while the summer truffle, as its name suggests, is harvested in the summer months, between June and August.
7. What about the yield and profitability of a truffle farm ?
Investing in truffle farming can be an attractive choice for good asset management. It is a profitable, sustainable and environmentally friendly investment. Indeed, on average, a truffle tree starts to produce around 5 to 8 years depending on the species, the planting density and the maintenance given to the orchard. During the 12th year, the indicative production per hectare can vary from 20kg to 90kg, in the case of Tuber melanosporum.
French truffle production has dropped dramatically over 100 years. It went from more than 1000 tons at the beginning of the 20th century, to an average of 30 tons per year between 1990 and 2000. Since the 1990's, more than 90% of the French truffle production comes from truffle trees planted with controlled mycorrhization, many of which are ROBIN TRUFFLE PLANTS.
10 questions/answers concerning truffle farming
The truffle is a fungus that grows in calcareous soil with a high PH (>7-7.5) that is perfectly draining and not too clayey. Before starting a truffle orchard project, we strongly advise you to do a soil analysis to check if your land is suitable for truffle growing.
The golden rule is to copy nature. Indeed, we advise you to choose a species of tree adapted to your region, that is to say a species that grows naturally in your geographical area and especially avoid choosing a species that is not naturally present in the surroundings, near the future plantation.
ROBIN® truffle plants are produced in ANTI-CHIGNON® buckets of 4 different volumes (from 0.4 to 3 liters). In a larger volume bucket, the root development will be more important as well as the number of root apices. The number of spores will also be greater and the plant itself will have a development proportional to the volume of the cup. A ROBIN® truffle seedling raised in a larger cup will therefore have a better potential.
We offer four different truffle species. The choice of the truffle variety best adapted to your project must be made according to the characteristics of your land and the climatic conditions of your region.
No, it is not recommended! Each variety of truffle has its own requirements, the soil favorable to one species (for example Tuber uncinatum) is not necessarily favorable to the White Truffle. If you wish to plant truffle plants mycorrhized with different species of truffles, you must keep a minimum distance of 15 to 20 meters between your two plantations.
You can keep your truffle plants for several days or even weeks before planting them, as they are delivered in their ROBIN ANTI-CHIGNON® cups which preserve the freshness of the root system. But you will have to take some precautions: Water them regularly every 2 to 3 days while waiting for planting and keep them outside, protected from frost and wind.
We formally advise against planting young plants mycorhized with truffles in an existing wood; the roots of the young plants will have a very high risk of being colonized by mycorrhizae already installed on the roots of the trees that make up your forest and will hinder the development of the truffle mycorrhizae present on the young truffle plants that you will have planted; if you wish to plant a truffle orchard, it must be done on a piece of land where there are no ectomycorrhizae trees.
Hoe and weed 2 to 3 times per spring and summer to prevent the young TRUFFIER ROBIN® plants from being invaded by weeds around the plants and to loosen the soil. Concerning irrigation, we recommend watering at planting and then once every 2 to 3 weeks in the absence of rain, from May to September with a contribution of 15 to 20 liters per plant to ensure the good recovery of the plants. The following years, it is necessary to continue the watering preferably with a system of micro-sprinkling on 2m² around each plant. Never use drip irrigation.
We do not recommend adding organic matter, mulch or any other material without first analyzing the soil. Only this analysis will be able to highlight possible deficiencies that should then be covered.
Truffle plants can be found and purchased in specialized nurseries such as ROBIN Nurseries. If you live near our sales points (department of 04 and 05), do not hesitate to visit us, you will benefit from precious advices before starting. Otherwise, you can buy your truffle plants directly online, via this website. They will be delivered to your home !