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Fertilizers promote plant growth and green lawns by helping plants meet their nutrient needs. Overuse or misuse of fertilizers can lead to excess nutrients, such as nitrates, contaminating your water supply This fact sheet provides you with information on common sense methods for using fertilizer which will help ensure that your water supply remains healthy and fertilizer free.

  1. Test your soil
    Nutrients [nitrogen (N), phosphorus (P) and potassium (K)] are applied to the land in the form of fertilizer. A soil test will determine the amount of fertilizer to apply to your landscape by testing the soil’s nutrient needs. If you use a lawn care service insist that they test your soil before any applications are made. Refer to the section on determining your soil nutrient needs .
  2. Choose the appropriate fertilizer types
    Common fertilizer is sold in a variety of concentrations of nitrogen (N), phosphorus (P) and potassium (K). Before purchasing a fertilizer product, read the label to ensure that you are buying the appropriate amounts (a soil test will help you determine which amounts are the best for your landscape).
    Fertilizer is available in slow-release or fast –release form. Fast release fertilizer releases the nitrogen almost immediately into the soil. Slow release fertilizer is a more controlled release of the nitrogen, which can reduce the chance of nutrients leaching into groundwater in areas such as sandy soils
    Adding organic matter such as composted yard trimmings and kitchen scraps to the soil improves plant growth by improving the soils ability to hold water and nutrients, stimulating the growth of beneficial microorganisms, and loosening heavy clay soils to allow better root penetration (note: this does not include animal waste). Before using compost you may want to analyze its contents.
  3. Applying the fertilizer
    Remember to always read and follow the label directions. Try not to use fertilizer on slopes or near sensitive resources. If you must use fertilizer near a water body, make sure a buffer strip of grass that has not been fertilized lies between the area of application and the water body. This will help prevent unwanted nutrients from running into the water. Apply as evenly as possible.
  4. Using a spreader
    Use a spreader that meets your needs. A rotary spreader is faster than a drop spreader. Make sure to calibrate your spreader before each use.
    • Fill the spreader on a hard surface, where any spills or excess can be swept up and reused.
    • When spreading fertilizer, close the hatch on the spreader when going over hard surfaces such as sidewalks or a driveway. Also make sure the hatch is closed when near wells and storm drains.
    • Keep track of where you have already applied fertilizer. Avoid going over the same area. This can lead to excess runoff and burned grass.
  5. Additional precautions
    • Never apply fertilizer directly to surface water.
    • Never wash fertilizer into streets or sidewalks.
    • Watch the weather! Too much rain can lead to runoff and will not have the desired affect. Fast release fertilizers should not be applied before a heavy rainfall. Any fertilizer application should be followed with watering.
    • Watch the timing of application. Do not apply fertilizer when the ground is frozen or during the very beginning of spring. Both could lead to excess run off.