Fertilizer Changes

When you buy lawn fertilizer this spring, you will notice that the turf fertilizer products sold at retail will no longer contain phosphorus or P.

Beginning April 1, 2010, new state regulations restrict the use, sale and display of turf fertilizer that is labeled as containing phosphorus or available phosphate. This type of fertilizer cannot be applied to lawns or turf in Wisconsin unless the fertilizer application qualifies under certain exemptions. Homeowners, renters and others who do their own lawn care will have to follow the new law. In addition, there are restrictions that professional lawn and landscape businesses must follow as well as sales and product display requirements for businesses that sell lawn or turf fertilizer.

Background

Phosphorus is an essential plant nutrient. Plants only absorb the amount of phosphorus they can use.
Extra phosphorus can wash into lakes, rivers and streams which can lead to algae blooms and declining water
quality. The law’s intent is to provide protection to Wisconsin’s water resources from phosphorus run-off.
Reading a Fertilizer Label Fertilizer labels carry a series of three numbers that indicate the amount of
total nitrogen (N), available phosphate (P) and soluble potash (K) in the package, also referred to as N-P-K.
In the picture, the product contains 24 percent nitrogen, 0 percent phosphate and 12 percent potash.
Fertilizers that also contain pesticides, sometimes called “weed and feed,” will also carry the three numbers for
nitrogen, phosphate and potash.

How to read the Label

Use Restrictions Under the new law, turf fertilizer that is labeled as containing phosphorus or available phosphate cannot be applied to residential lawns. There are some exceptions to this.

• New Lawns: Fertilizer labeled as containing phosphorus or available phosphate can be used for new lawns (seed or sod) during the growing season in which the grass is established.
• Phosphorus Deficient: Fertilizer that is labeled as containing phosphorus or available phosphate can be used if the soil is deficient in phosphorus, as shown by a soil test performed no more 36 months (three years) before the fertilizer is applied. The soil test must be performed by a soil testing laboratory.
• Non-turf Use: Fertilizer labeled as containing phosphorus or available phosphate can be applied to pastures, land used to grow grass for sod or any other land used for agricultural production or for home gardens.

Purchasing Turf Fertilizer with Phosphorus

Fertilizer retailers cannot display turf fertilizer that is labeled as containing phosphorus or available phosphate. However, retailers can post a sign indicating if fertilizer containing
phosphorus is available for purchase. If you need to purchase fertilizer because of one the exceptions listed
above, you should ask your retailer if fertilizer with phosphorus is available.