The key to successful establishment of a home lawn is proper soil preparation. Without this, most lawns will eventually fail. Proper preparation of the planting site can reduce many soil drainage and aeration, pH, and fertility problems that may not become evident until after the lawn is established. Correcting these problems after the turf is established is much more difficult than preventing their occurrence through proper site preparation, because the presence of the turf can limit your efforts. Thus, this critical step in the establishment process is important to long-term success of a lawn, efforts to provide the best possible soil conditions will not be wasted.

Eliminating weeds, especially perennial grassy weeds, will reduce competition with the developing turf grasses. Herbicides are valuable for eliminating weeds prior to lawn establishment. After eliminating weeds from the site, rough grade the area to facilitate surface drainage. Generally, a 1 to 2 percent slope away from buildings is adequate. If needed clear the site of all builders debris, spilled concrete, tree roots or dead vegetation that has resulted due to spraying.

Establish levels
To aid in establishing the final levels and to ensure a consistent cover of topsoil pegs will need to be driven into the soil to indicate both the depth to which excavation needs to take place as well as to indicate the depth to which the topsoil is to be filled. Establish your levels so as avoid puddling, gradients must slope away from buildings where possible. Ensure that all excess water is dealt with on site, no water must be led to run off onto an adjoining property. Make sure there is sufficient depth below pathways, driveway edges etc if topsoil is to be brought onto site. When establishing your levels keep in mind that a layer of between 100mm to150mm of high quality topsoil is required over the clay sub-grade to produce a high quality trouble free lawn.

Excavate as required
If subterranean drainage is required or sub-irrigation systems are to be installed, this is the best time to do it. Remember, good drainage is a must if a nice lawn is desired.

If additional topsoil is needed at the planting site, incorporate it into the existing soil during rough grading. Avoid using topsoil that is not similar to the soil onsite if it is not to be spread evenly over the site, or if it is not to be worked into the surface.
Amending heavy, clay soils or light, sandy soils with generous amounts of organic matter can improve the soil's drainage, aeration, and nutrient-holding capacity. If possible, apply a 50 mm layer of manure, compost, or some other quality organic material to your soil's surface. Use only well-rotted organic matter to avoid problems with weed seeds, diseases, or other factors that can inhibit or detract from turf growth and development. For topsoils with a high clay component an application of super phosphate at the rate of 50-100 grams per square metre and gypsum at the rate of 500- 1000 grams per square metre would be beneficial. Work the topsoil to a depth of 150mm to 200mm using a rotary tiller and grade the surface. This operation will uniformly incorporate all amendments. After rotary tilling, the soil particles should be marble sized or smaller.
 If the topsoil was removed during building leaving only subsoil or bare clay as is so often the case suitable topsoil will need to be imported and the following method needs to be followed.

Prepare the sub-grade by levelling as accurately as possible as this will minimise the topsoil required and also ensure that the depth of topsoil is consistent. Leave no lumps of clay or large stones on the surface. This will ensure a consistent pleasing to look at grass cover. If the topsoil depth is allowed to vary you will end up with a lawn that grows at different rates in different areas, this will result in the lawn looking patchy because the shallow areas will hold less water and nutrients for the healthy growth of the lawn. These areas will also tend to dry out quicker, stressing the grass. Time spent at this stage to achieve a level sub grade will go a long way to improving the final quality of the lawn. Getting the levels and drainage correct at this stage will prevent may problems such as puddling with soft muddy areas developing in the lawn during wet weather or following irrigation, dry patches and differences of compaction once the topsoil has settled from occurring. In addition if the sub-grade is uneven the topsoil overlay will settle unevenly, resulting in an uneven surface. An application of super phosphate at the rate of 50-100 grams per square metre and gypsum at the rate of 500- 1000 grams per square metre applied onto the clay and tilled in before the topsoil is spread will improve the quality of the clay base, thus improving the growing conditions and therefore the quality of the lawn. In addition the sub-grade may have become compacted during building operations and rough grading, especially if the ground was wet. This compacted layer must be broken up by rotovating or by other means

The choice of the grade of topsoil to be used will be determined by the location, the gradient, the use it will be put to and whether or not it will be irrigated. Ideally under normal circumstances one would choose to use fertile well-drained loam topsoil that has a good percentage of organic matter. Avoid using poor quality soils, or soils containing a large seed bank of weed seeds
Loam soil is composed of sand, silt, clay, and organic matter (humus) in evenly mixed particles of various sizes. Its structure allows high moisture retention good air circulation as well as good drainage. Loam soils are loose and look rich. When squeezed in your fist, moist loam will form a ball, which crumbles when poked with a finger. Loam soils normally absorb water and store moisture well. Most soils of agricultural importance are some type of loam.
Under certain circumstances a sand based growing medium may be recommended.

Applying the topsoil
Transport the soil onto the site by mechanical means or by barrow making sure to work from the furtherest point back towards the stockpile of soil so as to avoid compacting the soil. Level the site then firm down the soil either by using a light roller or by treading in by foot. It is most important to only firm the soil down and not to compact it, as this will have a negative impact on both the germination and growth of the young grass plants, as well as the rooting of sod. Rolling is done to consolidate the soil and to aid the settling process, please remember that you are not trying to make a road to drive a car on, but a seedbed to grow grass on.

Screeding
Screeding is the last step taken to level and even the surface. When pulling the screed or levelling bar along the ground, you will see soil building up along the leading edge and then again disappearing when you go over a hollow. When a little soil remains right along the leading edge without disappearing you have created a perfectly smoothed surface. Hard areas that have been exposed or have been created by the screeding process need to be cultivated then screeded again. This process may need to be repeated several times. The soil needs to be dry to screed. It is especially important to consolidate around the edges of pathways, gardens beds etc
Check that there is a loose even tilth of about 10mm- 15mm over the entire area, this is essential so as to provide the ideal conditions into which to plant the grass seed, to bed in instant lawn or to plant cores
Final screeding should be delayed until right before planting time if this is done too far in advance the soil may become crusted, this is of particular importance if the seed is to be planted by means of hydroseeding.

Careful turfgrass selection is an important first step in establishing, overseeding, or renovating a turfgrass. Many potential problems related to turf use, appearance, environment, insect or disease pests, and cultural practices can be avoided by properly choosing species and cultivars that best fit the situation in which the turfgrass will be grown. A turfgrass, when planted in areas where it is not adapted, often deteriorates or fails. The result of planting a turfgrass where it is not adapted is a poor-quality turf that requires excessive pesticide applications, fertilization, and replanting to retain a green ground cover. A high-quality turf may not be obtainable in this situation.
Following turfgrass selection, planting a lawn entails selecting the method of establishment, properly preparing the planting site, planting the turfgrass, and performing post-planting maintenance. Proper establishment is essential for long-term lawn health and attractive appearance

The final grass cover can be established in a number of ways, depending on the grass type being planted and the time of year the use the lawn is to be put to, personal preference and budget. This can be done for instance by mechanical seeding methods, by means of hydroseeding, by planting sprigs, cores, plugs, stolons or by rolling out instant turf.

Seeding
Is the most common method of establishing a lawn, which involves planting grass seed on a prepared seedbed. There are both advantages and disadvantages to seeding a lawn.

Although it appears there are fewer advantages than disadvantages to seeding a lawn, do not discount the importance of being able to select the desired species or cultivars and the fact that the turf plants develop in the environment in which they must ultimately survive. Seeding establishes a superior lawn.

Establishment by means of seeding
Providing enough seed to insure adequate coverage is important to seeding success, especially for grasses with a bunch growth habit. If the seed is applied unevenly or too little seed is applied the end result will be a patchy uneven lawn. Check edges and corners, seed may require to be hand sown on these areas.  Every seed will not produce a grass plant; a healthy, mature lawn usually averages six to eight turf plants per square inch. Different turf grasses have different seeding rates. These rates vary according to the size and weight of turfgrass seed. For instance, Poa praetense (Kentucky bluegrass) has a small seed and a high seed count per kilogram. On the other hand, Lolium perenne (perennial ryegrass) has a large seed and a lower count per kilogram. Avoid excessive seeding rates that can produce crowded, weak, unthrifty plants and increase seedling disease invasion. In addition, excessive seeding wastes seed and money.
The seed supplier will give you the correct application rate for the variety of seed supplied for you own local conditions.
After choosing the turfgrass and determining the seeding rate, be sure to distribute the seed uniformly over the planting area. Use a broadcast or drop spreader. It is advisable to apply half the seed in one direction, such as north to south, and then the other half in a different direction, such as east to west, to uniformly cover the entire area. After the seed is in place, there are two activities that are crucial to successful turf establishment. The first is making sure there is a good seed-to-soil contact. Accomplish this task by using a lawn rake to lightly mix the seed into the upper 5mm of soil. Follow the raking with a light rolling to produce a firm seedbed. A light rolling can be accomplished by using an empty water-ballast roller. Rolling not only increases seed-to-soil contact, but also firms the seedbed and slows drying of the soil.
Mulch with a thin layer of clean straw to prevent drying. Don't apply mulch heavily; you should be able to see soil beneath it. You do not have to remove the straw after the grass seed germinates. Grass seedlings will grow up through the light straw layer and gradually cover it as the straw decomposes. Raking off the straw would injure the young grass seedlings.
The second activity crucial to seed establishment success is to make sure adequate water is available throughout the germination process. At the time of planting, irrigate frequently and lightly, wetting the upper 15mm of soil. Continue watering during the period of germination. Water less frequently, but more thoroughly and deeply, as grass seedlings mature.
Average germination times vary according to the turfgrass species and the conditions under which germination takes place.
During the cooler months of the year as an aid to quicker germination a layer of frost protection or shade cloth can be laid over the site where the grass seed was planted.
This speeds up the germination process and causes the seed to germinate more consistently, it also helps to retain surface moisture longer and helps prevents rain out washing out seed on sloping ground. Remove the cloth when the young grass plants have reached between 10mm and 20mm.

Soil incompatibility sometimes develops when sod is grown on soil that is different from that of the lawn area. Soil incompatibility can result in poorly rooted sod that has little tolerance to environmental or pest stresses. Thus, in many situations, the advantages of seeding may outweigh the advantages of sodding.

If possible, choose sod grown on soils similar to the soils of the planting site or the sod may not "knit" to the soil properly and will gradually decline due to shallow rooting. Be sure to select fresh, healthy sod from a reputable dealer, and plant immediately after purchase. Look for sod with a thin soil layer as it will root faster and be easier to install due to its lighter weight.
Plant sod in a brick like pattern with sod edges tightly butting up to one another. Do not stretch sod it will shrink as it dries allowing weed invasion between pieces. On slopes it may be necessary to use small wooden pegs to help keep sod in place until it roots. Under good conditions sod will begin to root within 14 days. Avoid planting sod on excessively dry soils.
Using a lightweight roller, roll sod immediately after laying to insure close soil contact. Initially irrigate heavily to make sure water penetrates beneath the freshly installed sod and wets the soil. Until sod is established, continue to irrigate frequently, making sure soil is dampened to encourage root development.

Watering
Water the lawn to keep it damp at all times, without flooding or puddling. This may require many waterings per day, the soil used and the weather conditions prevailing at the time of establishment will determine how often it needs watering.
Once the seed has germinated, do not stop watering, however the frequency and amount of watering needs to be reduced. This is also the secret to success with instant lawn, it must be kept constantly damp until the turf has rooted, there after the frequency of watering can be slowly reduced.
Do not stop watering the grass before it has reached the mowing stage, as it is still juvenile and very water dependent. Gradually reduce the water applied until one reaches the stage where only enough water is supplied to meet the minimum needs of the lawn. Do not let the lawn dry out completely as it will cause considerable damage to the lawn at this stage.

Mowing
Do not mow while the new grass is wet.  It can be detrimental to the development of the new lawn grass to let it grow too long before the first mowing, on the other hand it will be very detrimental to cut the grass too short at this stage.
The first mowing should be done when the grass is between 60mm to 75 mm long. Mow to a height of 50 mm for the first 3 to 4 mowings thereafter the mowing height can be gradually lowered to a mowing height of between 35mm and 45 mm. Never remove more than one third of the leaf at any one time for example if the grass is 75mm do not mow lower than 50mm.

Under certain circumstances where a lawn has been managed incorrectly over a period of time, it can become compacted uneven and overrun with weeds making the lawn unsightly, at times the only solution is to remove the grass cover and start again.

If the preparation work was done correctly and high quality topsoil was used in the first instance and if no problems have developed as regards drainage. Spray out and kill all existing vegetation using a herbicide containing Glyphosate for example Roundup. (Note some plants such as white clover are very resistant to Glyphosate, good results have been achieved by adding Tordon Gold to the mixture)  It will usually take several weeks for the vegetation to die. It will take longer during the colder months than in the warmer months. Spreading 50mm well rotted compost over the entire area, in most cases lime would be needed to be applied. Some additional topsoil may need to be brought onto the site if the surface has subsided. Apply fertiliser and gypsum as required.
Cultivate using a mechanical cultivator or rotary hoe. Level with a screed or levelling bar. Level the site and re-seed.

Whether you establish a lawn by seed, hydroseeding, sod, or plugs, sprigs of stolons, the preparation steps are the same. Perennial weeds should be eliminated, the area should be graded, the soil should be amended and smoothed, and the best available turfgrass should be chosen for your specific needs. Then the guidelines for seeding and sodding should be followed. The final requirement is to provide adequate moisture for good establishment of the turfgrass. By establishing a healthy, vigorous turf on a properly prepared site, you will be well on your way to having an attractive lawn.