Truffles are a form of mushroom that develops underground in symbiotic association with the roots of trees. Their cultivation was made possible because of development of technology to inoculate host trees with the fungus, under controlled conditions. The use of inoculated trees to cultivate truffles was proven to be successful over the past 20 years in Europe.
There are only 3 truffle species that can be cultivated and have commercial value:
- Black winter (Perigord) Truffle
- Burgundy Truffle
- Bianchetto Truffle
The best climates for Perigord Truffles is the Mediterranean. It provides truffle with warmth, light and free draining soil with a pH of 7.9.
The Burgundy Truffle grows in coller regions in high density. A wide variety of soil types can serve them.
The Bianchetto Truffle likes sandy soil and works in a variety of climates.
To cultivate truffles, inoculated truffle trees are planted in orchards much like those for fruits and nuts, except that the crop appears below ground and is usually harvested with the help of trained dogs or pigs that can smell the truffles. Orchards should be organic and free of fertilizers, so the best truffle can be produced.
Truffles begin to appear several years (4-5 years) after the inoculated seedlings are planted and production can continue for decades. The onset and duration of production depends to some extent on the species of host tree. Yields vary dramatically: some farms produce as much as 150 pounds per acre each year while others produce little.
Because it is not possible to weed-out competing fungus species, the strategy behind truffle cultivation is to provide the truffle fungus with the conditions it needs to prevail in the competition against other fungi. This competitive advantage is given to the truffles in several ways:
- through careful site selection
- planting inoculated seedlings
- creating soil conditions better suited to truffles than other fungi.
Seedlings inoculated while they are still in the nursery give the truffles the advantage of being there first. It is more difficult for other fungi to become established on roots that are already colonized. Sometimes, it is necessary to add lime to raise the soil pH.