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Phosphorus Fertilizer Law Implementation

The Washington State law limiting the use of fertilizer containing phosphorus on turf went into effect January 1, 2013.

Any fertilizer labeled for use on turf, that lists phosphorus in its guaranteed analysis, may not be applied to turf in Washington State unless it is for the purpose of establishing grass or repairing damaged grass or for use in an area where a soil test taken within three years shows the soil to be deficient in plant available phosphorus.

In addition, it cannot be displayed or sold or unless it meets one of the exemptions. If it is labeled for establishing new grass, repairing turf or for use on shrub or flowerbeds, grass grown for sod, agriculture or trees it is exempt.

“Establishing grass or repairing damaged grass” is defined as using either seeds or sod, during the growing season in which the grass is established. Over seeding, patching and other similar activities are repairing turf. 

Additional Resources

We will continue to add information about fertilizer issues in Washington. Below are links to local ordinances affecting phosphorus fertilizer. If you have additional questions please contact Washington Friends of Farms & Forests. Resources for additional information.

Whatcom County Phosphorus Fertilizer Ordinance

King County Ordinance Background Information

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