LAFAYETTE, Ind. — A breakthrough discovery makes it possible for anyone to grow morel mushrooms, sometimes called sponge mushrooms, which are considered a culinary delicacy by many. U.S. Patent Number 6,907,691 B2 has been issued to Lafayette, Indiana biologist Stewart C. Miller, who has devoted 15 years to the project.

Photo of a cultivated Morel Mushroom

For centuries, morels have attracted mushroom lovers because they are delicious and fun to hunt. Yet there is a drawback: You need to know your mushrooms. Being able to grow morels in your backyard removes guesswork about whether a mushroom is safe.

“Morel Farms,” Miller’s new enterprise, is a 45-acre tract close to Lafayette that ultimately will be home to thousands of trees inoculated with the morel fungus. Currently, there are approximately 2,000 apple trees, 3,000 ash trees and 5,000 elm trees on the farm.

Miller solved the morel mushroom life cycle mystery after years of experimentation. He says, “I postulated the connection between the morel fungus and elm, apple, and ash trees in 1992. I spent several years proving my theory as to why morels are found around these dead trees.”

The discovery verifies the theory that there is a “symbiotic relationship” between the mushroom and selected host plants. “The morel fungus lives and grows inside the roots,” says Miller, who discovered this rare form of mutualism — mycorrhiza — in 1992. It took Miller ten more years to prove his discovery and ultimately photograph the hyphae of a single morel spore entering the roots of elm and ash trees. He first cultivated the elusive morels from the trees in 1999. A patent search and application that began in 2002 led to issuance of a patent on June 21, 2005.

How does the fungus develop into a morel mushroom? Miller coined the term “symbiotic disruption” to explain this event. A dying or dead tree stimulates the fungus inside the roots, causing the fungus to withdraw. Hardened nodules called “sclerotia” form below ground. With sufficient water and warmth, these sclerotia swell and, in spring, the mushroom pushes its way to the surface. The fungus and an inoculated tree may live in harmony for many years.

This past spring Miller had morels popping up in a four-year-old elm tree plantation. He has been inoculating trees with the fungus in a final cultivation experiment. Miller says, “Cultivation can become a successful enterprise for anyone who obtains a license. This year I inoculated several thousand elm tree seedlings and will sell some to interested individuals then plant the rest at Morel Farms.”

The morel mushroom harvest season is between March and June depending on climate and region. Anyone interested in raising morels can order inoculated trees at http://www.Morel-Farms.com/. Each tree ships with instructions.