Growing truffles is far from an exact science, but they are cultivated in quite large quantities. They grow in symbiosis with plant roots. They are called mycorrhizal fungi, and they mainly grow on the roots of oak trees. These can be injected with the spores of the truffle and planted out in scruffy plantations where the soil is poor, dry, meagre and calcareous. Because of climate change, these plantations may now need automatic watering systems.
It is usually possible to buy bunches of inoculated oak, evergreen oak or hazel saplings at the truffle markets to establish your own plantation. You may have to enclose it with electric deer fencing, as much to protect the ground against human, as faunal, incursion. There have been a number of cases of truffle-rustling in recent years – in one an intruder was shot dead: and serve him right, say the truffle growers.