Shiitake mushrooms in a growing room at Phillips Mushroom Farms, one of the big mushroom producers in Kennett Square.

Shiitake mushrooms in a growing room at Phillips Mushroom Farms, one of the big mushroom producers in Kennett Square.

Shiitake mushrooms in a growing room at Phillips Mushroom Farms, one of the big mushroom producers in Kennett Square.

Shitake mushrooms in a growing room at Phillips Mushroom Farms, one of the large mushroom producers in Kennett Square, Pa.