While fall is a busy time of year, be sure to set aside some time for your lawn. Good lawn care practices in the fall help maintain a healthy, vigorous lawn and can revive a declining lawn. Important fall chores include mowing, fertilization, weed control, and aerification.
Continue to mow the lawn until the grass stops growing. Kentucky bluegrass and other cool-season grasses usually stop growing in early November in Iowa. Mow bluegrass lawns at a height of 2 1/2 to 3 inches in the fall. When mowing, never remove more than 1/3 of the total leaf surface at any one time. For example, if your mowing height is 3 inches, mow the grass when it reaches a height of 4 1/2 inches.
Fall is the most important time to fertilize the lawn. Best results are typically achieved by fertilizing once in the spring and twice in the fall. Fall applications can be made in September and early November. September fertilization promotes a moderate rate of shoot growth and helps to thicken the turf. An application in early November (at the time of the last mowing) promotes root growth and early green up next spring. Apply 1 pound of actual nitrogen per 1,000 square feet in both September and early November.
Broadleaf Weed Control
Perennial broadleaf weeds, such as dandelion and plantain, can be controlled with the application of broadleaf herbicides from mid-September to early November. Most broadleaf herbicide products contain a mixture of 2 or all of the following chemicals: 2,4-D, MCPP, and dicamba. Fall applications of broadleaf herbicides are more effective and safer than those made in spring or summer. In preparation for winter, perennial weeds translocate carbohydrates (foods) down to their roots in the fall. Broadleaf herbicides applied from mid-September to early November will also be translocated to the weed's roots, resulting in excellent control. With gardening activities winding down in the fall, the risk of herbicide injury to vegetable and flower gardens, fruits, and ornamentals is also reduced. Broadleaf herbicides can be applied as liquids or granules. Before applying any pesticide, carefully read and follow label directions.
Lawns established on clay soils and those subject to heavy foot traffic would benefit from core aerification. Aerification relieves soil compaction, improves air and water movement into the soil, and helps reduce thatch accumulation. Aerifiy lawns in September with a machine that has hollow metal tubes or tines. These tubes or tines remove plugs of soil from the ground. Avoid spike-type devices that simply punch holes in the turf. For maximum benefit, the core aerifier should penetrate the soil to a depth of 2 to 3 inches. When finished, there should be approximately 20 to 40 holes per square foot. For the do-it-yourselfer, aerifying machines are often available at rental agencies. Aerification services are also available from most professional lawn care companies. After aerificaton, break up the soil cores by mowing or raking.
Fall is an important time in regards to the health and appearance of your lawn. Good cultural practices at this time of year help insure an attractive, healthy lawn.
This article originally appeared in the August 9, 2002 issue, p. 109.