PROPER LAWN CONSTRUCTION

Certain turf installations are unique. A golf green is a highly specialized use of turf that has no counterpart in landscaping. A rocky, steeply sloped highway embankment requires special techniques, too. This chapter will only deal with the installation of conventional lawn plantings such as those of the typical home or commercial business site. More specialized references are available for nontypical turfs. Six steps should be fol­lowed to ensure a beginning lawn every chance for success:

1. Plant at the proper time of year.

2. Provide the proper drainage and grading.

3. Condition the soil properly.

4. Apply fresh, vigorous seed, sod, plugs, or sprigs.

5. Provide adequate moisture to promote rapid establishment of the lawn.

6. Mow the new lawn to its correct height.

Time of Planting

Warm-season grasses grow best when the temperature is from 80° to 95° F. They are best planted in the late spring, just before the summer sea­son. In this way, they have the opportunity to become well-established before becoming dormant in the winter.

Cool-season grasses germinate best when temperatures are from 60° to 75° F. The best planting time for them is early fall or very early spring, right before the cool seasons in which they flourish. If cool-season

grasses are planted too close to the intensely hot or cold days of sum­mer and winter, they will die or go dormant before becoming well- established.

Grading and Draining the New Lawn

Each time the rain falls or an irrigation system is turned on, water moves across the surface of the soil as well as into it. Grading (altering level land so that it slopes slightly) can direct the movement of the surface water. Proper drainage permits the water to move slowly into the soil to the turf’s root system where it can be absorbed, yet pass beyond the root zone before it collects and does harm to the plants.

Even lawns that seem flat must slope enough so that water moves off the surface and away from nearby buildings. If a slight slope does not exist naturally, it may be necessary to construct one. A decline of between six inches and one foot per 100 feet is required for flat land to drain properly. Failure to grade lawns away from buildings can result in flooded cellars and basements.

Drainage is critical to the survival of the lawn, no matter what the species. Depending on the soil and site involved, good drainage may require nothing more than mixing organic matter with the existing soil. In cases in which the soil is heavy with clay, a system of drainage tile may be necessary.

If drainage tile is needed, it should be installed after the lawn’s grade has been established but before the surface soil has been conditioned. Regular four-inch agricultural tile is normally used, placed 18 to 24 inches beneath the surface. In a typical tile installation, the tile lines are spaced approximately 15 feet apart. Each of the lateral lines runs into a larger main drainage line, usually six to eight inches in diameter. This, in turn, empties into a nearby ditch or storm sewer (Figures 13-7 and 13-8).

Conditioning Soil

Suitable texture and proper pH are very important in soil that is to become a lawn. Most turfgrasses grow best in a loam or sandy loam soil with a pH that is neutral to slightly acidic (7.0 to 6.5). For a review of soil texture and pH, refer to Chapter 3.

The additives needed to improve the texture, drainage, or pH of the soil can be incorporated best with a rototiller or larger agricultural field

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figure 13-7. Drainage tile installation (drawing not to scale) (Delmar/Cengage Learning)

figure із-s. The flow of water through tile drainage system (drawing not to scale) (Delmar/Cengage Learning)

equipment (Figure 13-9). The tiller also loosens the soil surface and breaks it into smaller particles.

The tiller may do two additional things: chop up weeds growing on the site and bring rocks to the surface. Both can be bad for the new lawn. The stones mar the even texture of the lawn and, if large enough, can damage mowers and other maintenance equipment. They should be removed with a rake (hand or powered) before seeding. The weeds can cause future problems for the lawn, especially if they are noxious or other perennial types. It is best to eliminate them before installing the grass. A nonselective systemic herbicide or short-term soil sterilant can be applied. Both are expensive, widely used, and available under several brand names. Once the soil has been properly conditioned, it is ready to plant.