Spring has arrived in Southeast Michigan. Lawn mowers are abuzz and lawn treatment routines have begun. But before any fertilizer is applied, Michiganders should be aware of a new state law restricting the use of phosphorus on lawns, athletic fields, and golf courses.
Public Act 299, which took effect January 1, is designed to prevent excess phosphorus from entering Lake St. Clair and other waterways in Michigan. Phosphorus is the ‘P’ in N-P-K, which shoppers may see listed on the front of bags of fertilizer. This nutrient can run off lawns and sidewalks and into storm drains, which are directly connected to local surface waters.
Normally, aquatic plant growth and algal blooms are kept in check by naturally occurring, low levels of phosphorus in the water. But according to Michigan State University Extension, “Once [phosphorus] is freely available, plants can grow to excessive levels.” This chokes waterways of oxygen, which has a negative effect on water quality, fisheries, recreation, and property values, notes the Michigan Department of Agriculture and Rural Development.
Fortunately for Michigan gardeners, our lawns thrive and our gardens bloom with naturally occurring phosphorus in our soil. According to Michigan State University Turfgrass Science, “Phosphorus levels in soil are stable, and most Michigan soils have adequate phosphorus levels and therefore may not need continual applications of phosphorus.”
Exemptions in the phosphorus ban are allowed if a soil test (from this year or during the past three years) shows a lawn lacks enough phosphorus or if a homeowner is establishing new turf, whether from seed or sod. Michigan State University Extension offers soil testing and provides recommendations pinpointing a yard’s specific needs.
Other provisions in the law specify:
- Any fertilizer released onto a hard surface, such as a sidewalk or driveway, must be cleaned up promptly.
- Fertilizer cannot be applied to frozen soil or soil saturated with water.
- Applicators must maintain an application buffer from surface water (lake, river, stream) of at least 15 feet.
- A three-foot application buffer must be maintained if a spreader guard, deflector shield, or drop spreader is used.
- A 10-foot application buffer must be maintained if a continuous natural vegetative buffer separates the turf and surface water.
- Phosphorus applications for agriculture, gardens, trees, and shrubs are exempted.
Zero-phosphorous fertilizers can be identified at retail outlets by a zero for the middle number in the N-P-K ratio, which will appear on the packaging. A few organic examples are:
Ringer 0% Phosphate Lawn Restore: 10-0-6
Available at Allemon’s Landscape Center
Jonathan Green Organics Natural Beauty Fertilizer: 10-0-1
Available at DeRonne Hardware
Fertrell No Phos Custom Blend: 5-0-5
Available at Uncle Luke’s Feed Store
MSU Extension is offering a free online “webinar” regarding the new law on Wed., April 18th. The webinar, Be Phosphorus Smart: Michigan Fertilizer Law Amendments, will also be available for viewing on the website after April 18th. Visit http://www.bephosphorussmart.msu.edu/ for more information.
-Melissa Cooper Sargent
Printable pdf: New Fertilizer Law Protects Lakes