Section R. 285.627.2 - Storage and display conditionsRule 2.
(1) Balled stock, container-grown stock, potted stock, and nursery stock with manufactured balls shall be kept uniformly moist by surrounding or covering the root area with nontoxic, moisture-holding materials, or by irrigation sufficient to maintain the viability and vigor of the stock, and shall be kept under temperature and light intensity conditions that permit normal growth. Balled stock and stock with manufactured balls, displayed or stored on pavement or a similar moisture- impervious surface, shall be separated from that surface by at least a 4-inch layer of, or shall be surrounded by, peat, sawdust, shingletow, soil, or other similar moisture-holding material, which shall be kept moist at all times, or shall be kept under other conditions that will assure maintenance of moisture in the ball sufficient to preserve the vigor of the plant.(2) Bare-root nursery stock shall be kept under conditions of temperature and moisture that maintain viability. Moisture shall be supplied to the root system by high humidity conditions in storage or by covering the roots with soil, sawdust, peat, shingletow, or other moisture-holding material not toxic to plants, which covering shall be kept moist at all times.(3) Packaged nursery stock shall be stored and displayed under conditions that preserve the vitality of the plant and insure an adequate supply of moisture to the roots at all times.Mich. Admin. Code R. 285.627.2