Sod

Sod is the upper layer of turf that is harvested for transplanting. Turf consists of a variable thickness of a soil medium that supports a community of turfgrasses. Sod is typically made with grasses that spread laterally through the soil and form a dense mat. In British and Australian English, sod is more commonly known as turf and the term "sod" is mainly used in agriculture.

Sod is used to establish lawns or other greenways in spaces like golf courses or sports stadiums. Typically, after construction or other landscape disruption, builders, owners, and landscape specialists place sod to establish a grass cover.

Sod is grown on specialized farms; the grass is grown for 12 to 18 months before the sod is cut from the top layer of the soil and prepared for transportation. Sod is often cut in either squares or rolls, making it easier to transport and distribute. Different species of grass are grown in different geographic regions because of the differing climatic conditions. More recently, some producers have developed turf mixes that include wildflowers and other native plants.

Sod is used around the world for lawns, golf courses, and sports stadiums. In residential construction, it is sold to landscapers, home builders, and home owners, who use it to quickly establish a lawn and avoid soil erosion. Sod can be used to repair small, dead or damaged areas of lawn, golf course, or athletic field, and is used as a quicker alternative to re-growing from seed. Sod is also effective in increasing cooling, improving air and water quality, and assisting in flood prevention by draining water.

Scandinavia has a long history of employing sod roofing, and a traditional house type is the Icelandic turf house.

In the United States, following the passage of the Homestead Act by Congress in 1862, settlers in the Great Plains used sod bricks to build sod houses. This was effective because prairie sod of the Great Plains was dense and difficult to cut, and was nicknamed "Nebraska marble". Blacksmith John Deere made his fortune when he became the first to make a plow that could reliably cut prairie sod.

Different types of grass are used for sod installation.

Sod is grown on specialist farms, usually within 100 miles (160 km) of the target market. This minimizes both the cost of transportation and the risk of damage to the product. Sod-producing farms may have many varieties of grass growing in one location to best suit the consumer's use and preference. Sod is usually harvested 10 to 18 months after planting, depending on the growing climate. During cultivation, it undergoes fertilization, frequent mowing, watering, and in some cases, vacuuming to remove the clippings. It is harvested using specialized equipment that precisely cuts it to standardized sizes. Sod is typically harvested in small, square or rolled rectangular slabs, or 4-foot (1.2 m) wide rolls.