Sod is mature lawn that has been carefully and professionally cultivated; cut into thick squares or rolls with the underlying soil and roots, and shipped to a nursery or job site to be laid down for an "instant new lawn."
Once sod has been cut it is best to plant it within 24 hours. If working with a distributor you can order the sod ahead of time to be delivered on a certain day. If buying from a nursery make sure the pallets are not yellowed and that the sod looks moist and fresh. It will wilt and die quickly in hot weather, but will last a little longer in cool climates. If you cannot plant the sod immediately store the pallets in shade and keep them moist.
The cost of growing sod is appreciable. It takes up to 2 years for the grass to mature, during which time it must be cared for, fed, watered, and kept free from disease. It then needs to be cut, placed on pallets, and transported. For this reason a sod lawn costs about 20 times more than growing a lawn yourself from seed, usually anywhere from 14 - 60 cents per square foot (929 sq. cm). This assumes you will perform the preparation yourself.
To prepare for a sod lawn, old lawn and weeds must first be removed. The earth should be tilled 4 - 6 inches in depth (10 - 15 cm). If an irrigation system is to be installed, it is done at this time. If you want to add organic compounds or fertilizers to the soil, a second pass with the rototiller will work these in. Rake the surface to remove all roots, rocks and any hard clumps of soil. Make sure the ground is level so that water doesn't pool in any area of the yard. You can now roll the soil to firm up the surface. Make sure the soil is dry when you roll it and that the roller is not too heavy or the dirt will compact. When finished, the final grade should be about 1 inch (2.5 cm) below any bordering pavement such as patios, sidewalks or walkways. The soil attached to the sod blanket will fill this gap.
Speak to your sod producer or nursery about choosing the right sod for your needs. For example, some lawns tolerate wear from children and pets better than others. Your climate is also a major factor as is the composition of your soil. Loam is the best type of soil for lawn in general, but many people have sandy soil or heavy clay. Your sod provider can provide expert help. You can also have your soil tested for pH and composition if you aren't sure what type of soil you have.
Sod is heavy and laying it can be hard work. If you do opt to lay it yourself, the squares are placed side-by-side, seams butted up against one another tightly without overlapping. The longest straight line along a boundary should be laid first. If you don't have a boundary you can use a string line to make sure you lay the lawn straight. After laying 150 square feet (14 square meters) or so, water it lightly to keep it wet. Do this as you go along. Do not wait until the entire lawn is laid. As you lay the adjacent row the seams should be staggered, as if laying bricks. Sod can be cut to fit around trees or borders.
Once the lawn has been laid, use the roller on it to establish uniform pressure against the underlying ground. Avoid an excessively heavy roller as it might leave roller tracks.
The most important thing you can do for your new lawn while it is establishing itself in your yard is to water it daily for the first 7-10 days. It needs to be kept moist. If the climate is hot you may need to water it twice a day. After it establishes itself, normal watering is fine. People, pets and children should avoid walking on it as much as possible until it has a chance to take root.