Section R. 285.634.4 - Slowly available plant nutrientsRule 4.
(1) A fertilizer label shall not bear a statement that connotes or implies the presence of a slowly available plant nutrient, unless the nutrient is identified.(2) When a fertilizer label implies or connotes that the nitrogen is slowly available through the use of words such as "organic," "organic nitrogen," "ureaform," "long lasting," or similar terms, the guaranteed analysis shall indicate the percentage of water insoluble nitrogen. This requirement shall not apply to manipulated animal and composted vegetable materials distributed as such and not mixed with other materials. The label shall not bear a reference to slowly available nitrogen when water insoluble nitrogen is less than 15% of the total nitrogen.(3) The term "coated--slow release" may be accepted as descriptive of products and shall be allowed on labeling when the manufacturer can provide acceptable data substantiating the claim.Mich. Admin. Code R. 285.634.4