Mich. Comp. Laws § 333.29305

Sec. 305. (1) A grower shall post signage in a conspicuous location at each boundary line of each location where industrial hemp is grown. The signage must include all of the following: (a) The statement, "Industrial Hemp Registered with the Michigan Department of Agriculture and Rural Development". (b) The grower's name. (c) The grower's registration number. (2) The signage described under subsection (1) must meet all of the following requirements: (a) Be a minimum of 8 inches by 10 inches. (b) Use print that is clearly legible and not smaller than 3/8 inch tall. (c) Be made of weather-resistant material.