Truffles are an ecological group of fungi that grow and mature underground in association with tree roots, nourished by the carbohydrates shared by the roots of a host tree. The truffle fungus gives different valuable nutrients back to the tree roots in exchange. The "mushrooms", or spore bearing reproductive units, are acorn to walnut to tangerine-sized balls with a tough covering that encase the maturing spores within. (Picture a chocolate ganache ball enrobed in bittersweet chocolate... the chocolate truffle!) When the truffle spores mature underground, they have evolved to emit a fragrance that will attract truffle loving creatures (including humans) and signal that the mushroom is ready to eat. Once carried away and consumed, the spores are digested unscathed, thereby effectively ensuring it's survival in a new forest location.
About Truffles
Truffle fungi, aside from their edibility status, are important in the forest ecosystem. These are an important food sources world-wide for all kinds of mycophagist mammals (squirrels, flying squirrels, mice and others). While there are well over 140 species of truffles, only a handful are recognized as culinary fungi with significant market value, but that number is growing as truffles are better understood and researched in the USA.
Edible (and coveted) Truffle Species
The most coveted of truffles have traditionally been the White (Alba) truffle and the Black truffle (aka Perigord Truffle), famously grown or collected in Europe and exported to the USA. Recent advancements in the mushroom sciences have brought truffle cultivation to new heights in North America where now different Tuber species are being evaluated for cultivation. Each species has its own flavor signature and cultivation specifics. While certain regions of the USA have established truffle orchards including the above varieties, growers are testing other species to expand their offerings and success rate. One of the most common successfully cultivated truffles with a track record is the Burgundy Truffle, grown from the eastern seaboard through the Midwest wherever Oak and American Hazelnuts can thrive.
Truffle Cultivation
Truffles are grown in an orchard setting, much like fruit or nut trees. Site selection is critical to the success of the orchard. Truffle trees do best when planted into converted agricultural land as the soil is rich in bacteria (rather than forest fungi) which will not compete with the establishing truffle fungus. The soil needs to be well-drained and above pH 7.0, preferably pH 7.5. PH levels can be adjusted with the addition of lime and worked in as the orchard soil is plowed. If sod is being broken for the orchard, after plowing, the soil will need to be disked to prepare and level the planting site. The site should receive at least 6 hours of direct sunlight per day.
If you are just planting a few trees, it is still a good idea to know your soil pH and adjust it accordingly!
How many truffle trees to plant?
Because of the complicated mating nature of the truffle fungus, it is best to plant a variety of tree species, and more than one of each. We offer our trees in 2 tree species, Burr Oak and American Hazelnut, to increase your chances of success. We recommend planting the Burgundy Truffle (Tuber aestivum) which is adapted to our North American climate and can be harvested in the fall. These should be planted approximately 11 ft apart, kept weed free, and mulched with gravel if possible (not wood chips!) . By the time truffles begin to produce, there will be adequate shade cast by your collective planting.
Growing Truffle trees is not for the impatient. A orchard will take upwards of 5 years to produce.
Site Selection:
- Select an area that is not deeply forested
- Can be maintained free of weeds
- Cage the trees if browsing deer and rabbits is a problem
- Can be watered if necessary
- Lining a driveway is often a good choice because the you will see the trees frequently and be reminded to tend them. Also the neutral gravelly nature of such areas is great for the trees and fungus.
FIGURE 1
An established truffle orchard. Typically orchards take 5 years to start producing.
FIGURE 2
We found this Deer Truffle, Elaphomyces granulata, in a moss covered Norway Spruce forest in Sweden. We found these because they were dug up by wild pigs.
FIGURE 3
This specimen also has a common parasite growing on it, the Golden Thread cordyceps, which will eventually make way up and just above the soil surface to sporulate. The Deer truffle is not edible to us but it is to dozens of forest creatures!
Truffle Harvest
Truffles should only be harvested when they are dead ripe, like a peach. Fortunately, many critters will also smell them and you will notice by their activity that ripening might be occurring. For people that have a dog, you can train your dog to sniff out ripe truffles for you! While there are certain truffle dog breeds, any dog with a good nose can be trained with truffle oil in a scent-and-reward technique. This of course is harder with just a few trees and your dog may lose interest if truffles are slow in coming, so you have to keep at it!
Establishing a truffle orchard requires a great deal of research and preparation, not to mention acquisition of truffle-infected tree seedlings. Truffle cultivation is not for those people in a hurry. Depending on truffle orchard management, initial crops generally appear in five years however once producing, truffle trees will continue to produce for decades. Plus, you get a few beautiful trees and Hazelnut shrubs, important species for the food forest regardless of the truffle crop.
If you are interested in a larger scale orchard planting, contact us and we can put you in touch with the appropriate guidance.
What to Expect When Ordered
Our truffle seedlings are six to eight months in the making and are produced by a leading truffle seedling producer in the United States. They are sold in sets of four consisting of two each of Burr oak (Quercus macrocarpa) and American Hazel (Corylus americana). (Sorry, no substitutions!) The seedlings are inoculated with the Burgundy Truffle (Tuber aestivum) which is well suited to northern climates. Seedlings are guaranteed to have an established culture of the Burgundy truffle on their roots. Be aware that you are purchasing an inoculated seedling which may range in height from 4 to 8 inches. Seedlings are shipped in March and should be planted as soon as possible after they are received. If this is not possible seedlings may be stored refrigerated but the root ball must be kept moist and never allowed to dry out. You will be notified via email that seedlings have arrived and also when they are being shipped to you.
Why four seedling? Four is the minimum amount of seedlings that will give you the best chance of successful truffle cultivation. It all boils down to fungal sex(!). Different mating types are required to produce a fertile underground conk and chances for this to happen increase with more seedlings per given area.
