University of Maryland Extension

September Lawn Tips

lawn that has gone dormant

(More tips from HGIC)

  • The dormancy (browning) of cool-season grasses is a natural response that helps turfgrass survive drought and heat. Grasses that go dormant will usually green-up and grow vigorously again in the fall. If you have areas of your lawn that haven’t greened up yet you should consider reseeding them now.
  • If needed, this is the ideal time to begin a total lawn renovation project. Total renovation is best if your lawn is always failing due to poor soil, has over 50% weeds or is mostly dead. See our lawn renovation publication,  (PDF) HG 102 Lawn Establishment, Renovation, and Overseeding.
  • Whether renovating or just over-seeding, the seedbed should be raked vigorously with a metal rake to loosen the soil and promote good seed to soil contact. If your entire lawn is compacted, machine aerating will help improve seeding, water, and fertilizer penetration. Watch our turf establishment video for more information.
  • After seeding, the area should be lightly covered with straw and watered twice each day until the seeds germinate. As the grass grows and the roots develop you can allow the surface to dry out but the root zone needs to be kept moist.
  • The recommended grass for this region is the turf-type tall fescue varieties. If starting from scratch the lawn should be seeded at 8-10 lbs. per 1,000 sq. ft. If overseeding the seeding rate is half this amount. Fescue seed should germinate in about two weeks.
  • If broadleaf weeds are a problem, you can apply a liquid broadleaf weed killer after the newly seeded grass has been mowed at least 3 times or according to label directions.
  • It is too late to control crabgrass. Next spring prevent a crabgrass infestation by treating your lawn with a pre-emergent herbicide. However, improving the thickness of the lawn now by over-seeding, proper fertilization, and maintaining proper mower height, will greatly reduce crabgrass invading the lawn next summer.
  • Control broadleaf weeds like ground ivy, plantain, dandelion, and clover by using a combination broadleaf herbicide containing 2,4-D, MCPP, Dicamba or triclopyr.
  • Winter annual weeds like hairy bittercress, henbit and chickweed can be controlled now using a preemergent herbicide, labeled for broadleaf weeds, around the 1st-2nd week in September. But remember, you cannot apply a preemergent and sow grass seed at the same time.
  • Control perennial weeds like bermudagrass and nimblewill, in your lawn with spot treatments of glyphosate herbicide at least a week prior to renovation. Use this product with care; it will kill any part of the lawn that it is sprayed upon. Overseed with turf type tall fescue as recommended.
  • This is a good time to have your soil tested. Read (PDF) HG110 Selecting and Using a Soil Testing Lab and watch our video on how to take a soil test.
  • Cool season grasses, bluegrass and fescue should be fertilized in September and October with 0.9 lb. of nitrogen per 1,000 square feet. A single application cannot exceed 0.9 lb. of total nitrogen per 1,000 sq. feet and 0.7 lb. of soluble nitrogen per 1,000 square feet. Read (PDF) HG 112  Turfgrass Maintenance Calendars.
  • An important reason to test your soil is to determine if you need to apply lime. Soils with a low pH  benefit from the addition of limestone. The amount to apply will be indicated by soil test results.
  • If it is necessary to apply lime, spread it after all fertilizer has been applied and before the ground freezes. Refer to our website for information on getting your soil tested.
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