Restrictions on the use and sale of fertilizer containing phosphorus
Wis. Stat. § 94.643
in effect(1) Definitions. In this section:
(a) “Fertilizer” has the meaning given in s. 94.64 (1) (e), except that “fertilizer” does not include manipulated animal or vegetable manure or finished sewage sludge product.
(ag) “Finished sewage sludge product” has the meaning given in s. 94.64 (1) (fm).
(ar) “Manipulated” means ground; pelletized; mechanically dried; packaged; supplemented with substances, including plant nutrients, that do not contain phosphorus; or otherwise treated in a manner designed to facilitate sale or distribution as a fertilizer or soil or plant additive.
(b) “Turf” means land, including residential property, golf courses, and publicly owned land, that is planted in closely mowed, managed grass, except that “turf” does not include pasture, land used to grow grass for sod, or any other land used for agricultural production.
(2) Restrictions on use.
(a) Except as provided in par. (b), no person may intentionally apply to turf fertilizer that is labeled as containing phosphorus or available phosphate.
(b)
1. Paragraph (a) does not apply to a person who applies fertilizer in order to establish grass, using seed or sod, during the growing season in which the person began establishing the grass.
2. Paragraph (a) does not apply to a person who applies fertilizer to an area if the soil in the area is deficient in phosphorus, as shown by a soil test performed no more than 36 months before the application by a laboratory.
(c) No person may apply fertilizer, manipulated animal or vegetable manure, or finished sewage sludge product to turf when the ground is frozen.
(d) No person may intentionally apply turf fertilizer, manipulated animal or vegetable manure, or finished sewage sludge product to an impervious surface. A person who accidentally applies turf fertilizer, manipulated animal or vegetable manure, or finished sewage sludge product to an impervious surface shall immediately remove it.
(3) Restriction on sale. No person may sell at retail turf fertilizer that is labeled as containing phosphorus or available phosphate if the person knows that the purchaser intends to use the fertilizer for a purpose other than one of the following:
(a) For establishing grass, using seed or sod, during the growing season in which the purchaser began establishing the grass.
(b) For application to an area if the soil in the area is deficient in phosphorus, as shown by a soil test performed no more than 36 months before the application by a laboratory.
(c) For application to pasture, land used to grow grass for sod, or any other land used for agricultural production.
(4) Restriction on display. No person who sells fertilizer at retail may display turf fertilizer that is labeled as containing phosphorus or available phosphate. A person who sells fertilizer at retail may post a sign advising customers that turf fertilizer containing phosphorus is available upon request for uses permitted by sub. (2) (b).
(5) Penalty. Any person who violates this section may be required to forfeit not more than $50 for a first violation and not less than $200 nor more than $500 for a 2nd or subsequent violation.
Source: WI Statutes (Official Site)URL: https://docs.legis.wisconsin.gov/document/statutes/94.643Fetched: 10/7/2026