Posted: August 18, 2011
By John C. Harper II, Professor Emeritus of Agronomy
Revised by Peter J. Landschoot, Associate Professor of Turfgrass Science
The first step in lawn renovation is to correct the primary cause of turf deterioration. Such things as drought, excessive shade, tree root competition, poor drainage, soil compaction, inadequate fertility, acid soils, weed or insect infestation, disease, thatch build-up, improper mowing, poorly-adapted grass species and cultivars, and others may contribute to poor turf. Most of these problems can be corrected by renovation, proper turfgrass selection, and improved maintenance practices.
Shade problems may require removal of some trees, pruning, and planting turfgrass species that are adapted to shaded conditions.
Poor drainage can often be corrected by breaking-up compacted soil or through installation of drainage tile. Where surface drainage is insufficient, the site may have to be re-graded so that water is removed from the site.
Soil fertility and acidity can be determined if inadequate fertility or acid soils are limiting turf growth by testing the soil. Soil testing services are available at a nominal fee from the cooperative extension office in your county.
Thatch is a tightly intermingled layer of partially decomposed grass stems and roots which develops beneath the actively growing green vegetation and above the soil surface. Thatch decreases the vigor of turfgrasses by restricting the movement of water, fertilizers, and pesticides into the soil.
Mowing most lawns at two inches or above and on a regular basis as long as the grass is growing is recommended. No more than one third of the total leaf surface should be removed at a given mowing. All mowing equipment needs to be sharpened and adjusted periodically.
Species and management is perhaps the most common causes of lawn deterioration.
Weed Control. As a general guide, if only easy-to-kill broadleaf weeds such as dandelion or plantain are present, 2,4-D may be applied and the seeding may be done in two weeks. A combination of 2,4-D, MCPP, and dicamba is recommended if the weed population contains many different weed species or hard-to-kill weeds such as knotweed, clover, or ground ivy. A six week waiting period will be required following use of this herbicide combination. These steps should be followed in sequence as one continuous operation.
- Mow. Mow area closely (approximately ¾ inch) and remove all clippings, leaves, and other debris by sweeping or raking.
- Thatch. Thatch is best removed with dethatching equipment with vertically rotating blades or aeration equipment. Dethatch only during periods of cool weather and adequate moisture. Thatch should not be removed during periods of high temperatures, drought, or during late fall when winter desiccation may occur.
- Cultivation. Mechanical aerating machines which remove plugs of soil from the turf area are used to alleviate soil compaction and to prepare a partial seedbed. Aeration should consist of a minimum of eight to ten times over the area.
- Lime and Fertilizer. Lime should be applied in accordance with a soil test.
- Drag. Following cultivation, lime and fertilizer application, drag the area with a large door mat or section of chain link fence.
- Seedbed preparation. Repeat the cultivation operation to further prepare the seedbed for seeding.
- Seeding. A turf type disk seeder is the best tool for seeding. When no disk type seeder is available, uniformly broadcast the seed over the area. The total seed quantity should be divided into two equal lots, sowing one lot in one direction and the second at right angles to the first. Good quality seed of permanent species adapted to the environmental and use conditions should be used.
- Drag. Following seeding, drag the area again to work the seed into the seedbed and to cover the seed with a light layer of soil.
- Roll. The seed should be firmed into the soil by light rolling.
- Mulch. Where there is little existing grass, a very light application of straw mulch may be applied to retain moisture and to promote germination. The mulch should not be too heavy to smother or completely shut off light to the existing grass.
Water. The seeded area should be kept moist until the seed has germinated and the seedling plants have become well established.