DEPARTMENT OF AGRICULTURE AND RURAL DEVELOPMENT  
PESTICIDE AND PLANT PEST MANAGEMENT DIVISION  
REGULATION NO. 634. COMMERCIAL FERTILIZERS  
By authority conferred on the director of the department of agriculture and rural  
development by section 8516 of the natural resources and environmental protection act,  
1994 PA 451, MCL 324.8516)  
R 285.634.1 Fertilizers for agricultural crop production; specialty fertilizers  
micronutrient content.  
Rule 1. Plant nutrients in addition to nitrogen, phosphorus, and potassium when  
mentioned in any form or manner must be guaranteed. Guarantees must be made on the  
elemental basis. Sources of the elements guaranteed, and proof of availability must be  
provided to the director upon request. Except guarantees for those water-soluble nutrients  
labeled for hydroponic or continuous liquid feed programs, and guarantees for potting  
soils and lawn soils, the minimum percentages that will be accepted for registration or  
licensing, or both, are as follows:  
Element  
Percent  
1.0000  
0.5000  
1.0000  
0.0200  
0.1000  
0.0005  
0.0500  
0.1000  
0.0500  
0.0005  
0.1000  
0.0500  
Calcium (Ca)  
Magnesium (Mg)  
Sulfur (S)  
Boron (B)  
Chlorine (Cl)  
Cobalt (Co)  
Copper (Cu)  
Iron (Fe)  
Manganese (Mn)  
Molybdenum (Mo)  
Sodium (Na)  
Zinc (Zn)  
History: 1979 AC; 2022 MR 5, Eff. Mar. 14, 2022.  
R 285.634.2 Rescinded.  
History: 1979 AC; 2022 MR 5, Eff. Mar. 14, 2022.  
R 285.634.3 Placement of micronutrient guarantees on label.  
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Rule 3. Only the guarantees or claims for the plant nutrients listed in R 285.634.1 will  
be accepted. Proposed labels and directions for the use of the fertilizer must be furnished  
with the application for license or registration, or both, upon request. Any of the elements  
listed in R 285.634.1 that are guaranteed must appear in the order listed and must  
immediately follow guarantees for the primary nutrients of nitrogen, phosphorus, and  
potassium, if present.  
History: 1979 AC; 2022 MR 5, Eff. Mar. 14, 2022.  
R 285.634.4 Slowly available plant nutrients.  
Rule 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.  
History: 1979 AC.  
R 285.634.5 Specialty fertilizer labeling format.  
Rule 5. The following information, if not appearing on the face or display side of a  
container in a readable and conspicuous form, shall occupy at least the upper third of a  
side of the container and shall be considered the label:  
(a) Net weight.  
(b) Brand name and grade.  
(c) Guaranteed analysis:  
Total nitrogen (N)  
_______________%  
___________% Ammoniacal nitrogen (if claimed)  
___________% Nitrate nitrogen (if claimed)  
___________% Water insoluble nitrogen (required when  
terms described in R 285.634.4 are used)  
Available phosphoric acid (P205)  
Soluble potash (K20)  
________________%  
________________%  
Additional plant nutrients  
(d) Sources of nutrients when shown.  
(e) Potential acidity or basicity in terms of calcium carbonate equivalent per ton (if  
claimed).  
(f) Name and address of the registrant.  
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History: 1979 AC.  
R 285.634.6 Soil conditioners.  
Rule 6. A registration shall not be issued for a product that represents itself by label or  
supplemental material, leaflets, or advertising to improve the physical nature of the  
soil by altering the soil structure, by making soil nutrients more available, or otherwise  
enhancing the soil media resulting in beneficial crop response, unless the manufacturer  
or distributor of the product can provide scientifically acceptable data from  
experimentation which give reasonable assurance that such benefits as claimed can be  
expected to occur and are of definitive benefit to plant growth.  
History: 1979 AC.  
R 285.634.7 Tonnage reporting.  
Rule 7. Tonnage reports and fee payment must be on a form provided by the director of  
the department must be for the annual period of January 1 to December 31. The reports  
must cover all fertilizers, soil conditioners, and peat products sold for application in this  
state.  
History: 1979 AC; 2022 MR 5, Eff. Mar. 14, 2022.  
R 285.634.8 Rescission.  
Rule 8. Regulation No. 200, being R 285.200 of the Michigan Administrative  
Code and appearing on pages 3108 to 3111 of the 1964-65 Annual Supplements to the  
Code, is rescinded.  
History: 1979 AC.  
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