Minnesota has recently passed a law that restricts the use of lawn fertilizers containing phosphorus, the primary nutrient that turns lakes green with algae. Excess algae and weed growth is a major problem in many Minnesota lakes and waterways. Too much algae lowers oxygen levels and darkens the water, causing a devastating effect on fish populations. While phosphorus is necessary to grow healthy lawns, soils already have an adequate amount in many parts of Minnesota. In these instances, adding more phosphorus in fertilizer is not needed and will not benefit lawns. Healthy lawns can be maintained with phosphorus-free fertilizers. As of January 1, 2004, fertilizers containing phosphorus cannot be used on lawns in the Twin Cities metro area (Anoka, Carver, Dakota, Hennepin, Ramsey, Scott and Washington counties). Greater Minnesota is restricted to lawn fertilizers with three-percent or less phosphate content. On any bag or box of fertilizer, there is a string of three numbers. The middle number indicates phosphorus content and should read “0” in the Twin Cities seven county metropolitan area, and “3” or less in Greater Minnesota. There is currently a bill being considered at the legislature that, if passed, will require that only phosphorus free fertilizer be used on lawns across the state. Fertilizers containing phosphorus may be used on lawns if a soil test indicates that it is needed or if you are establishing a new lawn. These restrictions apply only to lawn fertilizer and do not apply to fertilizers used for agricultural crops, flower and vegetable gardening, or by trained staff on golf courses. Fertilizers, leaves, grass clippings, eroded soil and animal waste are all sources of phosphorus. When they are swept or washed into the nearest street or storm-drain, they end up in local lakes or rivers. Minnesotan’s can do their part to protect water quality by following Minnesota’s new phosphorus lawn fertilizer law; keeping leaves and lawn clippings out of gutters, streets and ditches; cleaning lawn and garden equipment on the grass, not on hard surfaces; and never washing or blowing soil or grass clippings into the street. Other practical tips to protect Minnesota’s lakes and streams include: o Pick up pet waste promptly. Pet waste can contain harmful bacteria as well as nutrients. Never drop pet waste in the streets or ditches. o Control soil erosion around the house. When left bare, soil is easily washed away with rain, carrying phosphorus with it. o If you accidentally spill or spread fertilizer on a hard surface, clean it up immediately. For more information on lawn care and the new phosphorus lawn fertilizer law go to the MDA home page at www.mda.state.mn.us, click on water and land, then lawn care and water quality, scroll down to the sections on phosphorus.
