Mycologist and author Peter McCoy of RadicalMycology.com takes on the question - I'm wondering if you have any information about inoculating trees to grow truffles. I have read that hazelnuts are sometimes used in truffle production and, while there are nurseries that sell (large quantities of) inoculated trees, I can't find any information about doing it yourself. It seems like the method is to introduce some kind of inoculum into sterilised seeding media just prior to germination, but what is the inoculum? Ground up truffles? Can you grow out the inoculum prior to introducing it to the soil to expand your supply? To learn more about Peter and see all of the ASK Peter episodes visit permaculturevoices.com/peter.   Support the show at permaculturevoices.com/support.