Fertilizing Your Lawn

Premise: A healthy dense lawn helps prevent pollution from reaching Maryland's streams and rivers and the Chesapeake Bay. Proper lawn feeding and a maintenance program are essential in reducing and preventing water pollution.


Fertilizers provide the nutrients for the maintenance of a healthy lawn. One should use only the minimum amount of fertilizer to achieve a healthy lawn. Too much fertilizer applied at the wrong time can harm your lawn as well as pollute the watershed. Plus, excess fertilizer causes rapid lush growth that is more susceptible to disease and more attractive to pests.

Major nutrients of fertilizers (e.g., 10-6-4 which numbers as listed on fertilizer bags represent the percentage of the major nutrients) essential to plant health and their function:

  • Nitrogen (N - first number 10) - promotes overall grass shoot growth
  • Phosphorous (P - second number 6) - promotes root growth
  • Potassium (K - third number 4) - aids in grass withstanding stress, e.g., drought

Timing of Fertilization

  • Cool season grasses such as tall and fine fescues, bluegrass, and rye grass are best fertilized in late summer and early fall
  • Warm season grasses such as zoysia and Bermuda grass are best fertilized in June and July

Rate of Application - minimal amounts of fertilizer need for maintaining a healthy lawn

  • Tall fescue, bluegrass, and ryegrass - 1 lb. nitrogen per 1,000 sq. ft in September followed by a second pound of nitrogen in October. (Note: A fertilizer listed as containing 10% nitrogen as in above illustration is equivalent to providing 1 lb. nitrogen.)
  • Fine fescues -1 lb. nitrogen per 1,000 sq. ft. in October
    • Optional - Apply an additional 1/2 to 1 lb. nitrogen per 1,000 sq ft. in May or early June if considered necessary.
  • Warm season grasses - 1/2 to 1 lb. nitrogen per 1,000 sq. ft. in July (zoysia grass) or August (Bermuda grass).

Other Factors Contributing to a Healthy Lawn

  • Use grass seed that is suited for Maryland and for the situation - Tall fescues are best for sun to partial shade; fine fescues, such as creeping red fescue, are appropriate for shady areas. Zoysia grass and Bermuda grass do well in the sun.*
  • Do a soil analysis every 3 to 5 years to check pH (should range from 6.0 to 6.5) and fertility. This analysis can be done through the University of Maryland for $5.00. Call MD Farm & Home, 301-342-2507, for a soil sampling kit. Also, a simple consumer-intended pH testing kit is available at the garden center.**
  • Mow tall and fine fescues at 2 1/2 to 3 1/2 inch height; bluegrass and ryegrass at 2 to 3 inches, and zoysia grass or Bermuda grass at 1/2 to 1 inch. It is best to remove no more than 1/2 inch of the blade each time you mow. Proper mowing height can reduce weed problems by 50 to 80 percent by shading out weed seeds.
  • For established lawns, water only as needed. It is preferable to water early in the morning to a depth of 4 to 6 inches - check depth by plunging a screwdriver into the ground. Frequent and shallow watering can damage the lawn. It is normal for lawns, especially those composed of bluegrass, to go dormant, i.e., turn brown, during dry periods. It generally resurrects itself with the rains.

*Stadler Nursery carries Class Act grass seed which is a blend of tall fescues recommended for use in Maryland, for sunny to partial shade areas. For the shady lawn, Stadler offers creeping red fescue, a fine fescue grass seed, also recommend for the Maryland areas.

** Stadler Nursery carries Rapidtest pH soil test kit.

For more information, see Fact Sheet 702, "Lawns and the Chesapeake Bay," available from Maryland Farm and Home, 301-342-2507, which is apart of the Maryland Extension Service.

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