Criticisms of Lawns

A number of criticisms of lawns are based on environmental grounds:

• Many lawns are composed of a single species of plant, or of very few species, which reduces biodiversity, especially if the lawn covers a large area. In addition, they may be composed primarily of plants not local to the area, which can further decrease local biodiversity.
• Lawns are sometimes cared for by using synthetic pesticides and other chemicals, which can be harmful to the environment, especially when misused. Consequently, in Canada, for example, over 130 municipalities and the entire province of Quebec have now placed restrictions on the cosmetic use of synthetic lawn pesticides as a result of health and environmental concerns. Additionally, Sweden, Denmark, Norway, Kuwait and Belize have also placed restrictions on the use of the herbicide 2,4-D.
• The use of pesticides and synthetic fertilizers, which require fossil fuels to be manufactured, has been shown to be detrimental to combating global warming, whereas organic techniques help reduce global warming.
• Maintaining a green lawn sometimes requires large amounts of water. This was not a problem in temperate England where the concept of the lawn originated, as natural rainfall was sufficient to maintain a lawn's health. However the exporting of the lawn ideal to more arid regions of the world, such as the U.S. Southwest and Australia, has crimped already scarce water resources in such areas, requiring larger, more environmentally invasive water supply systems. 
• Grass typically goes dormant during cold, winter months, and turns brown during hot, dry summer months, thereby reducing its demand for water. Many property owners consider this "dead" appearance unacceptable and therefore increase watering during the summer months. Grass can also recover quite well from a drought.
• In the United States lawn heights are generally maintained by gasoline-powered lawnmowers, which contribute to urban smog during the summer months. The U.S. Environmental Protection Agency found that in some urban areas, up to 5% of smog was due to pre-1997 small gasoline engines such as are typically used on lawnmowers. Since 1997, the EPA has mandated emissions controls on newer engines in an effort to reduce smog.

However, using ecological techniques, the impact of lawns can sometimes be reduced. Such methods include the use of local grasses, proper mowing techniques, leaving grass clippings in place, integrated pest management, organic fertilizers, and introducing a variety of plants to the lawn.

In addition to the environmental criticisms, some gardeners question the aesthetic value of lawns.

One positive benefit of a healthy lawn is that of a filter for contaminants and to prevent run-off and erosion of bare dirt. Highway construction projects in the United States now routinely include replanting grasses on disturbed soils for this purpose, although they are not maintained as lawns. It is important to note that a healthy lawn does not necessarily mean that synthetic pesticides need to be used, as organic solutions exist.