Where Do Truffles Grow?

“Well, if Albion is a pig,” replied this recent college graduate with a degree in biology, “his truffles are probably of the mushroom variety.”

I had no idea.

What are truffles?

While truffles certainly come in the rich, delicious chocolate variety, they’re also a type of underground fungus, or mushroom — equally rich-tasting and delightful, but much more of the savory persuasion.

Hundreds of varieties of the mushrooms exist. The edible species are highly prized as a culinary delicacy, and they are used in Middle Eastern, French, Spanish, Italian and Greek cooking. They grow wild in the forests of Europe, North Africa, the Middle East and North America.

European white truffles (Tuber magnatum) can cost as much as $3,600 a pound — making them ounce for ounce the most expensive food in the world. Since most folks can’t afford to buy truffles by the pound, they buy Black Diamonds, a small packet of shavings from French Black Perigord Truffles (Tuber melanosporum) that sell for a few hundred dollars. The native truffles that grow in the Pacific Northwest of the United States are not the same as European truffles, nor do they command the same high price.

So, why would the diet of the rich and famous interest you? Because farmers in North America are finding that they, too, can grow — and sell for a profit — European truffles.

David Cassford wanted to do something with his 11 acres besides mow it. As a native to the Isle of Wight, he has a particular fondness for the filbert (hazel) nut. Thinking he might like to plant a grove of filbert trees, he researched them online — and discovered truffles.

Where do truffles grow?

Truffles grow in a symbiotic (give-and-take) relationship on the roots of trees — particularly filbert (hazelnut) and certain species of oak trees.

“When the trees are dormant in the winter,” says Cassford, “the truffles take their nutrition from them. When the trees wake up in the spring, they take nutrition from the truffles.” Truffles are thus harvested, using trained dogs to sniff them out, in the winter months before the trees begin to feed on them.

Any dog can be trained to harvest truffles. “They are trained much like drug dogs or currency dogs,” says Pat Martin, president of the North American Truffle Growers Association, and co-owner with her husband, John, of Virginia Truffles in Rixeyville, Virgina. The Martins use two Labrador retrievers at their truffiere, Le Clos de la Rabasse. Although the Lagotto Romagnolo, from Italy, is bred specifically for truffle harvesting, Martin said that any breed that likes food rewards will work. In the world of truffles, the dog training is the easy part.

Preparing the site for your truffiere requires the most labor. Remove all trees, stumps and root systems from previous growth, then test your soil. Since truffles require a soil pH of 8 to 8.3, United States growers must apply agricultural lime before planting.

“Send your soil samples to A&L Laboratories in Memphis, Tennessee for testing,” says Martin. They might be the only lab outside of France that will test your soil according to truffle growing standards and for the micronutrients needed specifically for this crop.

Once your soil is prepared, consider irrigation. Maturing trees require about an inch of water a week. When growing truffles, you do not plant one or two trees; you plant one or two acres of trees. If watering the trees proves too labor-intensive, you will likely abandon your orchard and your investment.

Truffles also need four well-defined seasons. According to Franklin Garland, owner of Garland Truffles in Hillsborough, North Carolina, they grow best in a temperate climate without extreme temperature variations. Snow is good because it insulates the ground and keeps the truffles warm. But freezing temperatures of around 20 degrees and below for more than several days will damage them and decrease their value. And since you harvest them during the winter, you will not be able to dig them up if the ground freezes. Garland says the mid-Atlantic region is best. In the United States, black Perigord truffles and Burgundy truffles (Tuber uncinatum) are currently being produced in North and South Carolina, Tennessee and Virginia. Other farms in West Virginia, Maryland and Delaware are close to harvesting.

If your property is surrounded by mature, native hardwoods, experts recommend you leave a 30-to-40-foot buffer between the existing forest and your plantings. The European truffieres do this to keep competing fungi in the forest from taking hold in their truffle trees. Since growers in the U.S. must amend the soil to sustain the truffles, however, it’s questionable whether the competing fungi can successfully establish themselves in the new environment. Martin’s daughter, Olivia Taylor, a graduate student of mycology, is writing her thesis on this very question. Until her findings are published, though, it is better to be safe than sorry, and build the recommended buffer zone.

If there’s so much money to be made, why aren’t more homesteaders growing truffles? It ultimately comes down to what Garland calls the “human factor.” Since it takes six to eight years to harvest a marketable crop, most folks give up. While you are not reaping the fruit of your labor, your orchard still requires maintenance. Garland used the tomato plant to explain. “You can plant one tomato plant, no problem. You plant 10 plants, no problem. But when you plant 500 tomato plants, it gets difficult. You can’t plant and come back three months later expecting to find tomatoes. There won’t be any. There’ll be weeds.” A lot of folks start off gung-ho building a truffiere, and then fail to maintain it. In fact, according to Garland, 50 percent of truffle orchard failures are abandoned because the person didn’t have the patience or the energy necessary for the long haul.

Another consideration is that while you maintain the health of the trees above the ground, you cannot see what is growing below the surface. In fact, you don’t even know if the inoculation of the tree roots with the truffle spores actually took. However, a few tell-tale signs will give one hope. Truffles emit volatile organic compounds that act as an herbicide and kill the vegetation at the base of the tree. This area is called a brule — the French word for burned. Another sign is the growth of moss, and a third, for black truffles, is the presence of puffballs. If you see no signs, all is not necessarily lost — a window of opportunity exists to reinoculate the trees, and amend the soil nutrients, between the sixth and eighth years.

Since truffles grow in a symbiotic relationship with trees, the grower not only needs to think of the safety of his truffles, but the trees as well. The Martins have been able to protect their trees from pest and disease damage using preventative and natural methods. A fence keeps out deer, which will eat young trees, and skunks, possums and raccoons, which will dig around the roots.

“The oaks are hardy enough to resist,” says Martin, “but the filbert trees are now subject to the Eastern Filbert Blight.” There is no treatment for this blight, and according to Martin, once one tree gets it, it will wipe out an entire orchard — a major investment of time and money.

Planting a truffle orchard is not cheap. Cassford’s soil required an application of 20 tons of lime. He also installed an irrigation system and purchased 500 trees at $24 each. The initial investment for 1 acre cost him around $25,000. But Cassford is a hard worker. He tends his trees like they are his babies. And in five more years, he expects to harvest enough truffles to pay for this investment. After that, it’s all profit.

If you make it to harvest, selling is not a problem. The market for truffles is hungry. A farmer with a 1/2-acre orchard can make it with only one to two restaurant clients. Brokers that specialize in fine food products or mushrooms buy truffles; and if you live near a high-end farmers’ market, you could sell them by the ounce. Martin said you can vacuum seal them, pack on ice, and ship next-day air anywhere in the country. Restaurants would buy from you before they’d pay the freight on European shipments.

If you cannot market your own crop, Garland will buy them for $500 a pound. The cheapest he has seen truffles was $300 a pound in 1979. But for the last five years (ones of recession) the price has remained stable at $800 a pound.

The newest contender in the alternative farming arena, truffles have not yet won widespread trust. Those who have cast their lots, however, have confidence in what they are doing. “We firmly believe we will be successful, or we wouldn’t be doing ­­it,” says Martin.

“Yeah, just don’t bet the farm on it,” counters her daughter Taylor, with a wink and a chuckle.

As for Cassford, the hard work is behind him. All he needs is time, and a dog.

Resources for Growing Truffles

Want to start a truffle orchard while you still have a spring in your step? Here are a few resources to help you out.

The North American Truffle Growers’ Association is a non-profit organization established for the support and education of truffle growers in North America. Members include truffle growers in Tennessee, Virginia, North and South Carolina, Iowa, Kentucky, Arkansas, Idaho and Oregon. For more information, visit The North American Truffle Growers’ Association.

Garland Truffles of Hillsborough, North Carolina, has been in business since 1979. The company sells inoculated trees, educational materials, and supplies for the truffle grower. Its staff also hosts tours of the facilities, complete with truffle tastings by appointment. For more information about truffle growing or the company’s products, visit Garland Truffles.

In 2007, John and Pat Martin founded Virginia Truffles in Rixeyville, Virginia. They sell inoculated trees from their nursery and offer consultations for the beginning truffle grower. For information about establishing a truffiere and more, visit Virginia Truffles.

Located in Napa, California, the American Truffle Co. hosts the annual Napa Truffle Festival. The company also provides seedlings inoculated with either black Perigord or Burgundy truffle spores and the education necessary for a beginning farmer to succeed in truffle cultivation, all in a partnership arrangement. For more information, or to read archived issues of the company’s newsletters, visit American Truffle Co.

Carol J. Alexander writes about truffles and other alternative farming practices from her home in the Shenandoah Valley of Virginia.