Chapter 22 Lawn construction.
Upon completion of this chapter, you should be able to
* describe four methods of lawn installation
* outline the steps required for proper lawn construction
* explain how to calibrate a spreader
Selecting the Method of Lawn Installation
There are four methods that may be used to install a turfgrass planting:
* Sodding Plugging
* Sprigging and stolonizing
The method selected depends upon the species of grass, the type of landscape site, and how quickly the turf must be established.
Seeding is the most common and least expensive method of establishing a lawn. The seed can be applied by hand or with a spreader on small sites. On large sites, a cultipacker seeder (pulled by a tractor) or a hydroseeder (a spraying device that applies seed, water, fertilizer, and mulch at the same time) may be used. The hydroseeder is especially helpful for seeding sloped, uneven areas, Figure 22-1.
When a lawn is needed immediately, sodding may be selected as the method of installation. Sod is established turf that is moved from one location to another. A sod cutter is used to cut the sod into strips. These are then lifted, rolled up, and placed onto pallets for transport to the site of the new lawn, Figure 22-2A, B, and C. At the new site, the sod is unrolled onto the conditioned soil bed. The effect is that of instant lawn, Figure 22-3. Sod is produced in special nurseries where it can be grown and harvested efficiently and in large quantities. Sodding is much more costly than seeding. However, the immediacy is important to some clients, and it is necessary on sites where seed might wash away.
[FIGURE 22-1 OMITTED]
[FIGURE 22-2A OMITTED]
[FIGURE 22-2B OMITTED]
[FIGURE 22-2C OMITTED]
Plugging is a common method of installing lawns in the southern sections of the United States. Certain grasses, such as Bermuda, St. Augustine, and zoysia, are not usually reproduced from seed. Instead, they are usually placed into the new lawn as plugs of live, growing grass. Since the growing season in the southern regions is longer than elsewhere, the plugs have time to develop into a full lawn. Plugging is a time-consuming means of installing a lawn, which is its major limitation. However, plugging is necessary for many warm-season grasses that are poor seed producers. On large sites, some mechanization of the planting is possible.
[FIGURE 22-3 OMITTED]
Sprigging and Stolonizing
Like plugging, sprigging and stolonizing are more commonly used with warm-season grasses than cool-season grasses. A sprig is a piece of grass shoot. It may be a piece of stolon or rhizome or even a lateral shoot. Sprigs do not have soil attached and so are not like plugs or sod. They are planted at intervals into prepared, conditioned soil. Several bushels of sprigs are required to plant 1,000 square feet. If done by hand, the process is slow and tedious. Mechanization can lessen the time required.
Stolonizing is a form of sprigging. The sprigs are broadcast (distributed evenly) over the site and covered lightly with soil. Then they are rolled or disked. Since each sprig is not individually inserted into the soil, this method is faster.
Proper Lawn Construction
If the lawn is to be of the best quality, it must be given every possible chance for success. Proper construction of the lawn is vital. Six steps should be followed by the landscaper to assure a successful beginning for the lawn.
* Plant at the proper time of year
* Provide the proper drainage and grading
* Condition the soil properly
* Apply fresh, good-quality seed, sod, plugs, or sprigs
* Provide adequate moisture to promote rapid establishment of the lawn
* Mow the new lawn to its correct height
Time of Planting
Lawns in southern sections of the country require warm-season grasses. Such grasses grow best in day temperatures of 80 to 95 degrees F. It is most effective to plant them in the spring, just prior to the summer season. In this way, they have the opportunity to become well established before becoming dormant in the winter.
Cooler northern regions require cool-season grasses to yield the most attractive lawns. Bluegrasses and fescues germinate best when temperatures are in the range of 60 to 75 degrees F. These lawns thrive in locations where days are cool and nights are warm. The best planting time for these grasses is early fall or very early spring, prior to the ideal cool season 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 become dormant before becoming well established.
Grading and Draining the New Lawn
Each time the rain falls or a sprinkler is turned on, water moves into the soil and across its surface. Grading (leveling land so that it slopes) directs the movement of the surface water. Drainage allows the water to move slowly down into the soil to prevent erosion or puddling.
Even lawns that seem flat must slope enough to move water off the surface and away from nearby buildings. If a slight slope does not exist naturally, it may be necessary to construct one. A fall (grade) of between 6 inches and 1 foot over a distance of 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 of water into and through the soil is important. Without a supply of water to their roots, neither grasses nor any other plants can live. Without water drainage past their roots, turf grasses and other plants can be drowned. Depending upon the soil in the particular lawn area involved, good drainage may require nothing more than mixing sand with the existing soil to allow proper water penetration. In cases where the soil is heavy with clay, a system of drainage tile may be necessary.
[FIGURE 22-4 OMITTED]
[FIGURE 22-5 OMITTED]
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 4-inch agricultural tile is normally used, placed 18 to 24 inches beneath the surface. Tile lines are spaced approximately 15 feet apart, Figure 22-4. Each of the lateral tiles runs into a larger main drainage tile, usually 6 to 8 inches in diameter. This, in turn, empties into a nearby ditch or storm sewer, Figure 22-5.
Where the soil is naturally sandy, no special consideration for drainage may be necessary.
Conditioning the Soil
Proper soil preparation requires an understanding of soil texture and soil pH.
Soil texture is the result of differing amounts of sand, silt, and clay in the composition of the soil. A soil that contains nearly equal amounts of sand, silt, and clay is called a loam soil. Loam soils are excellent for planting. Soil textures such as sandy loam, clay loam, and silty clay loam are named for the ingredient or ingredients that make up more than one-third of the composition of the soil. For example, the composition of sandy loam is more than one-third sand. Silt and clay each make up more than one-third of the composition of silty clay loam, and hence, it is less than one-third sand. In conditioning soil for lawn construction, clay, sand, silt, or humus (organic material) may be added to bring the existing soil closer to a medium-loam texture.
Soil pH is a measure of the acidity or alkalinity of soil. A pH measurement of less than 7.0 indicates increasing soil acidity. As the pH increases beyond 7.0, the soil becomes more alkaline or basic. Most turf grasses grow best in soil with a neutral pH (expressed as 7.0) to slightly acidic pH (6.5).
The measurement of soil pH is obtained from a soil test. Soil tests are usually available through county Cooperative Extension Services. Also, pH test kits can be purchased at a reasonable cost, allowing landscapers to make their own determination of pH much more quickly.
If the pH of soil is too acidic, it is usually possible to raise the pH by adding dolomitic limestone. The limestone should be applied in the spring or fall. As the following chart illustrates, the amount applied depends upon the texture of the soil and how far the natural pH is from 6.5 to 7.0.
Where it is necessary to lower the pH of the soil to attain the desired level of 6.5 to 7.0, landscapers commonly use sulfur, aluminum sulfate, or iron sulfate.
The attainment of a suitable texture and the proper pH are very important in the conditioning of lawn soil. Equally important is the removal of stones from the surface layer of the soil, the loosening of the soil to a depth of 5 or 6 inches, and the incorporation of organic matter into the soil.
Stones may be removed by hand, by rake, or by machine. If the lawn is to be smoothly surfaced, even the smallest surface stones must be discarded.
Decaying organic matter creates humus, a valuable ingredient of soil. Humus aids the soil in moisture retention. It also helps air reach the soil. Organic matter can be added to the soil during its conditioning with materials such as peat moss, well-rotted manure, compost, or digested sewage sludge. The landscaper may choose the material that is most easily available and relatively low in cost.
All necessary soil additives (pH adjusters, organic matter, sand, and fertilizers) can be worked into the soil at the same time. This is done most effectively with a garden tiller, which also loosens the soil surface and breaks the soil into small particles, Figure 22-6. Once the soil has been properly conditioned, it is ready to plant.
Planting the Lawn
Seed. Seed is applied to the prepared soil in a manner that will distribute it evenly. Otherwise, a patchy lawn develops. When applied with a spreader or cultipacker seeder, the seed may be mixed with a carrier material such as sand or topsoil to assure even spreading. The seed or seed/ carrier mix is divided into two equal amounts. One part is sown across the lawn in one direction. The other half is then sown across the lawn at a 90-degree angle to the first half, Figure 22-7.
[FIGURE 22-6 OMITTED]
[FIGURE 22-7 OMITTED]
Placing a light mulch of weed-free straw over the seed helps retain moisture. It also helps to prevent the seed from washing away during watering or rainfall. On a slope that has not been hydro-seeded, it is wise to apply erosion netting over the mulched seed to reduce the possibility of the seed washing away, Figure 22-8.
Sod. Sod must be installed as soon after it has been cut as possible. If not, the live grass will be damaged as a result of the excessive temperatures that build up within the rolled or folded strips of sod. Permitting the sod to dry out while awaiting installation can also damage the grass and result in a weak, unsatisfactory lawn.
The soil should be moist before beginning installation of the sod. The individual strips are then laid into place much as a jigsaw puzzle is assembled. The sod should not be stretched to fit, as it will only shrink back later, leaving gaps in the lawn surface. Instead, each strip should be fitted carefully and tightly against the other strips. Using a flat tamper or roller, the sod should be tamped gently to assure that all parts are touching the soil.
[FIGURE 22-8 OMITTED]
Plugs. Plugs are small squares, rectangles, or circles of sod, cut about 2 inches thick. Their installation is similar to that of groundcovers. They are set into the conditioned soil at regular intervals (12 to 18 inches), in staggered rows to maximize coverage. The top of each plug should be level with the surface of the conditioned soil. The soil should be moist but not wet at the time of installation. This prevents some of the plugs from drying out while others are still being installed.
Sprigs. Sprigs are planted 2 to 3 inches deep in rows 8 to 12 inches apart. In hand installations, rows are not drawn. Instead, the sprigs are distributed as evenly as possible over the prepared soil surface and pushed down into the soil with a stick. As described earlier, stolonizing uses a top-dressing of soil over the sprigs and eliminates the need for individual insertion. The soil should be moist, but not overly wet, when planting begins. If the lawn area is large, planted areas should be mulched and lightly rolled as the installation progresses. Waiting until the entire installation has been completed could result in drying out of the sprigs.
The Importance of Watering. Water is essential to the growth of all plants. As long as grass is dormant in the seed, it needs no water. However, once planted and watered, the seed swells and germinates. At that point, an uninterrupted water supply is very important. The soil surface must not be allowed to dry until the grass is about 2 inches tall. Watering several times a day, every day for a month, may be necessary.
Caution should be taken to keep the new seedlings moist without saturating the soil. Too much moisture can encourage disease development. The use of a lawn sprinkler is a much better method than simply turning a garden hose onto the new grass. With a sprinkler, the water can be applied slowly and evenly.
The First Mowing. The first mowing of a new lawn is an important one. The objective is to encourage horizontal branching of the new grass plants as quickly as possible. This creates a thick (dense) lawn. The first mowing should occur when the new grass has reached a height of 2 1/2 to 3 inches. It should be cut back to a height of 1 1/4 to 1 1/2 inches. Thereafter, different species require differing mowing heights for proper maintenance. For the first mowing, it is a good practice to collect and remove the grass clippings. After that, clipping removal is usually unnecessary unless the grass has grown so tall between mowings that clumps of grass are visible on the lawn. Grasses used for soil stabilization do not require mowing.
Calibrating a Spreader
Two types of spreaders are used to apply seed, fertilizer, and other granular materials to lawns. These are the rotary spreader and the drop spreader. The rotary type dispenses the material from a closed hamper onto a rotating plate. It is then propelled outward in a semicircular pattern. The drop spreader dispenses the material through holes in the bottom of the hamper as it is pushed across the lawn, Figure 22-7. In both types, the amount of material applied is controlled by the size of the holes through which the material passes, and by the speed of application. Therefore, the spreader must be calibrated to dispense the material at the rate desired. For materials that are applied often and by the same person, the spreader need only be calibrated once, with the proper setting noted on the control for future reference. Different materials usually require different calibrations, even when the rate of application is the same.
The object of calibration is to measure the amount of material applied to an area of 100 square feet. A paved area such as a driveway or parking lot is an excellent calibration site. Afterwards, the seed or other material can be swept up easily for future use. Covering the area with plastic is also helpful in recollecting the material.
The spreader should be filled with exactly 5 pounds of the material being applied. Selection of a spreader setting near the center of the range is a good point at which to begin.
The material is applied by walking at a normal pace in a straight line. The spreader is shut off while it is being turned around. Each strip should slightly overlap the previous one. When an area of 100 square feet has been covered once, the spreader is shut off. The material remaining in the spreader is then emptied out and weighed. By subtracting the new weight from the original weight, the quantity of material applied per 100 square feet is determined. The spreader can then be adjusted to increase or reduce the rate of application.
Briefly answer each of the following questions.
1. How does the cost of sodding compare to that of seeding?
2. Which method has a more immediate effect, seeding or sodding?
3. Which lawns are commonly started by plugging, sprigging, and stolonizing?
4. Which method of lawn installation and establishment requires the most time?
5. At what time of year should warm-season grasses be planted?
6. At what time of year should cool-season grasses be planted?
7. At what time of year should bluegrasses and fescues be planted? Why?
8. Why is it important that soil drain properly?
9. What size of agricultural drainage tile is recommended for lawn use, and how is it spaced?
10. Define soil texture.
11. What type of soil is considered ideal for planting?
12. Explain soil pH.
13. What is a neutral pH level?
14. If soil pH is raised, does the soil become more acidic or more alkaline?
15. If a sandy soil has a pH of 5.0, how many pounds of dolomitic limestone per 1,000 square feet are needed to raise the pH level to that required for a lawn?
16. If the soil mentioned in question 15 covers a lawn area of 3,000 square feet, how much limestone should the landscaper purchase?
17. What are the water requirements of a new lawn?
18. At what height should a lawn mower be set for the first mowing of a new lawn?
19. What is meant by the calibration of a spreader?
20. How is a spreader calibrated?
1. Invite a Cooperative Extension Service agent to visit the class for a discussion of soil testing. Ask the agent to demonstrate how a soil sample is collected and to explain how landscapers in the state can arrange to have soil tested.
2. Obtain several inexpensive pH testing kits. Bring in soil samples from gardens for testing.
3. Construct a lawn. If materials for proper lawn construction are available at the school, install a new lawn there. If budget restrictions prevent this, volunteer as a class to work for a nearby park, institution, or property owner in return for equipment and materials for the project.
4. Visit a sod farm if one is located in the area.
5. Borrow several spreaders for calibration. (Families of students might be one source.) If there is no budget for seed, substitute sand for demonstration purposes.
Jack E. Ingels
State University of New York
College of Agriculture and Technology
Cobleskill, New York
Amount of Dolomitic Limestone Applied Per 1,000 Square Feet of Lawn Soil Texture Natural Soil Sandy Loam Clay or Silt pH 4.0 90 lb. 172 lb. 217 lb. pH 4.5 82 lb. 157 lb. 202 lb. pH 5.0 67 lb. 127 lb. 150 lb. pH 5.5 52 lb. 97 lb. 120 lb. pH 6.0 20 lb. 35 lb. 60 lb. pH 6.5-7.0 None needed None needed None needed
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||SECTION 2 Landscape Contracting|
|Author:||Ingels, Jack E.|
|Publication:||Landscaping Principles and Practices, 6th ed.|
|Date:||Jan 1, 2004|
|Previous Article:||Chapter 21 Selecting the proper grass.|
|Next Article:||Chapter 23 Landscape irrigation.|