A lawn is a cultivated, mowed field planted with grass and sometimes clover and other plants. Lawns are typically planted near homes, often as part of gardens. The purpose of a lawn is to create a comfortable space upon which games can be played, picnics held, and any other social events happen. Typical middle-class homes in North America and the United Kingdom commonly have lawns surrounded by a hedge or fence.
Lawns are also a common feature of public parks and the playing surface for most outdoor sports including golf, tennis, football, soccer, bowling, and others. In sports venues, the term lawn is usually replaced by turf or green.
Homeowners wishing a more lush and green lawn sometimes attempt to "roll the lawn," by pushing weights around the lawn area, either mechanically with a lawn roller or by hand. This is a process that can have the opposite effect unless the lawn, or a part of it, is only recently established from seed. Rolling an established lawn can simply compact the soil. This has the combined effect of removing air pockets necessary for aeration , preventing water from seeping into the soil, and generally prohibits external nutrients from reaching the roots - overall resulting in an unhealthy lawn. Rolling a lawn can help when soil is very loose, or turves have been recently laid, or when new grass seedlings are sprouting. Rolling new seedlings encourages them to spread out and grow in a flatter, wider habit. An alternative is to use a core aerator or lawn scarifier (also called lawn aerator scarifier) to improve lawn health. On the other hand, some choose to over sand their lawn, which can result in a more even growth of grass.
Lawns are sometimes criticized by environmentalists for several reasons:
- Many lawns tend to be composed of a single species of plant which reduces biodiversity, especially if the lawn covers a large area.
- Lawns are sometimes cared for using pesticides and other chemicals.
- Lawns are usually composed primarily of plants not local to the area which can decrease local biodiversity.
- Maintaining a green lawn often requires large amounts of water. The use of such large amounts on plants that are often unsuited for their environment puts a strain on water supplies in arid areas, requiring larger more environmentally invasive water supply systems.
However, using ecological techniques, the impact of lawns can sometimes be reduced. Such methods include the use of local grasses, using only organic fertilizers, and introducing a variety of plants to the lawn. In highly arid areas, some people are shifting to stone gardens.
The history of lawns is rather poorly known, according to "The Lawn Expert" (D G Hessayon ISBN 0903505487). In the days before lawnmowers, maintaining a lawn would have been almost impossible, yet there is no historical record of how this might be done.
Lawns do not necessarily have to be composed of grass. Other possible plants are camomile and thyme.