How Lawns Work
Lawn grass does more than require the care of its owners. It helps them fit in with the neighborhood, improves property values and establishes the initial filter in the local aquifer (the area of plants, soil and rock layers that purify water before it reaches the water table). For a lawn to do all this, it must be composed of plants that fit in with cultural expectations and be maintained in a way that optimizes its usefulness. To these ends, scientists have hybridized grasses to provide lawn grasses that can grow successfully in different climates and be mowed to create a crop of plants that all of us recognize as a "lawn". In order to successfully function as part of the environment and culture, though, lawn grasses need maintenance.
Lawn Care Establishes Function
Lawn care starts and keeps lawns healthy. Thorough soil preparation, accurate seeding rate and frequent hydration allow healthy seed to germinate and develop strong roots and thick crowns. When established according to the needs of the grass variety and soil type, lawn grass crowds out most weeds. The right grass properly started in the right place becomes a moisture magnet, holding rainwater, controlling runoff and enhancing the aquifer.
Lawn care practice can also control how effectively lawn grasses function by modifying the environment in established lawns. Aeration pulls plugs of earth and deposits them on the surface, allowing light, air and water to infiltrate to plant roots. Top dressing lawns with humus, compost or manure provides nutrients and texture for heavy soils where starting a lawn from scratch is not an option. Thatching, a technique of cutting into the surface of the lawn, tears up compacted grass cuttings and organic matter often found on heavy or compacted soil. Aeration, top dressing and thatching all serve to re-establish the basic functions of grass.
Lawn Care Manages Growth
Most grasses, left uncared-for, will grow, set seed and reseed themselves several times in one season. They are self-propagating, going dormant several times a year, depending on whether they are "warm-season" or "cool-season" grasses. Lawn care encourages continuous grass growth through the process of mowing. Removing part of the plant prohibits the development of seed and forces new bursts of growth to compensate for this wide scale "deadheading". Lawn grasses then grow quickly, generating bursts of oxygen, contributing to the familiar "new-mown" smell.
Since constant growth depletes available nutrients in the soil, lawns need additional nitrogen for success. Whether lawn care is performed by the homeowner or a professional, a balance of mowing, watering and periodic applications of slow-release nitrogen fertilizer manage growth to keep grasses "green" through periods when they would normally be dormant. This constant growth, although a chore, is the way lawn care makes a lawn out of a short-season plant.