The idea of growing mushrooms itself is not that strange. Edible fungi are a staple ingredient in cuisines around the globe. Though perhaps not as widely used in the U.S. as in other parts of the world, mushrooms are relatively common in American cooking. The unusual aspect of mushrooms — especially some gourmet varieties — is the way they are grown.
Today, the practice of placing mushroom spawn inside of logs or bales of hay is not as common as it once was. However, some species, especially the highly valued shitakke mushroom, are still often grown this way, especially on organic farms. Commercial fungiculture often takes place in climate- and humidity-controlled rooms where the mushrooms are grown in trays under ideal conditions. The substrates used can include straw, corncobs, coffee grounds or ground nut shells.