University of Maryland Extension

Fertilizing - Lawns

typical front lawn   lawnmower on front lawn       

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Fertilizer is essential for maintaining healthy, relatively weed and disease free grass. Timing, type, and amount of fertilizer play important roles in properly managing your lawn and helping to be responsible for protecting our natural resources. Our information is based on University research and can differ from commercially available recommendations.  The purpose of lawn fertilization is to provide nutrients to encourage healthy active turf growth and to help overcome stressors such as drought, weeds, and grubs, etc.

Since the Maryland Lawn Fertilizer Law passed in 2011, which also applies to commercial lawn businesses, we are reminded not to overfertilize. The law addresses nitrogen and phosphorus applications only because they have a negative impact on water quality in our streams, rivers and the Bay. 

  • Late summer into the fall is the recommended time to apply fertilizer to cool-season grass like tall fescue. Zoysia is fertilized in the late spring into summer. See (PDF) HG 112 Turfgrass Maintenance Calendars for Maryland for additional information.
  • Excessive nitrogen applications in spring and summer increases disease problems and reduces stress tolerance.
  • Use a lawn spreader to apply fertilizer, never by hand. Most brand name fertilizers will list the proper setting to apply the correct amount of nitrogen to your lawn. 
  • Knowing the size of your lawn helps to determine how much fertilizer to buy. Bags typically cover 5,000, 10,000 or 15,000 square feet. See (PDF) HG 306 How to Measure Your Yard. 
  • Perform a soil test to check phosphorus levels and pH. For other tips see (PDF) "How to Fertilize Your Lawn Responsibly". 
  • Lawn fertilizers now sold in the state are formulated to comply with lawn fertilizer law. Lawn maintenance fertilizers have zero phosphorus in them and contain at least 20% slow-release nitrogen. Specialty products containing phosphorus are still available and may be used when a soil test indicates the need for phosphorus or when a homeowner or business is establishing, repairing or patching a lawn.
  • Follow University of Maryland Extension lawn fertilizer schedule for timing and amount of nitrogen. 
  • Sweep or blow fertilizer and lawn clippings that landed on hard surfaces back into grassy areas. 

Resources:

(PDF) HG 112 - Turfgrass Maintenance Calendars for Maryland Lawns
(PDF) MDA 15.06 - How to Choose a Lawn Care Service
(PDF) MDA 15.07.14 - Maryland's Lawn Fertilizer Law
(PDF) MDA 15.01.13 Fertilizer Use Act of 2011

Video:
How to Fertilize your Lawn and Protect the Chesapeake Bay

 

 

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