Pennsylvania Fertilizer Law for Home Gardeners

Fertilizers are typically packaged with numbers that indicate the ratio of nitrogen, phosphorus, and potassium contained within (such as 10-10-10). If you have purchased lawn fertilizer in the past few years, you may have noticed that the middle number on the bag is zero, indicating that it contains no phosphorus. This is due to a turfgrass fertilizer law adopted in Pennsylvania in July 2022. The law aims to reduce harmful environmental impacts from improper fertilizer application. The overuse of phosphorus fertilizer causes one such detrimental effect. Phosphates in runoff can cause increased growth of algae and aquatic plants, eventually causing decreased oxygen in water systems—a process called eutrophication. In addition to limiting the use of phosphorus in fertilizer, the 2022 law establishes other precautions for the benefit of the environment. If you take care of a lawn, here are changes that you need to be aware of:

• Nitrogen and phosphorus fertilizers may not be applied after December 15, before March 1, or anytime when the ground is snow-covered or frozen to a depth of at least two inches.
• With some exceptions, fertilizer cannot be applied within fifteen feet of the top of a bank of a lake, pond, wetland, or flowing body of water (stream, river, or creek).
• Fertilizers cannot be applied to impervious surfaces such as driveways, sidewalks, etc. Fertilizer spills on these surfaces must be cleaned up immediately.
• Fertilizer should not be applied before a heavy rain.
• All fertilizer must be applied using appropriate equipment that is correctly calibrated.
• As mentioned above, the law states that phosphorus should be omitted from turfgrass fertilizer, except for some specific instances, such as establishing a new lawn. But even in that case, the law specifies maximum amounts of phosphorus that can be applied and maximum amounts of nitrogen (Nitrogen is limited to 0.9 pounds of total nitrogen and 0.7 pounds of available nitrogen per 1000 feet per application.) However, if you have results from a soil test kit recommending a rate above the law's maximum amounts, you may follow the test's recommendations instead.

Commercial lawn care services should be aware of the changes outlined in the law and will treat your lawn accordingly. However, you may want to ask them some questions to ensure this.

For more specific information about the law, see the Pennsylvania Department of Agriculture's fact sheet. If you need assistance determining the correct amount of fertilizer to apply to a lawn, contact your local county Garden Hotline for support!