Lawn Glossary
Acid soil: Soil with a pH measure below 7. Most soils in the eastern third of the United States and Canada and along the West Coast are naturally acidic. Also called sour soil.
Aeration: Introduction of air to compacted soil by mechanically removing plugs of topsoil. Aeration helps oxygen, water, fertilizer, and organic matter to reach roots. Also called core cultivation or aerifying.
Alkaline soil: Soil with a pH measure above 7. Many central and western states have alkaline soils. Also called sweet soil.
Amendments: Organic or mineral materials, such as peat moss, compost, or perlite, that are used to improve the soil.
Annual: A plant that germinates, grows, flowers, produces seeds, and dies in the course of a single growing season. Annual grasses are sometimes used as nurse crops to protect slower-growing seed, or to overseed warm-season grasses during their dormancy.
Automated home sprinkler system: A method for watering lawn and plantings via underground pipes and sprinklers. A controller, when set to run, directs water to one station (valve) at a time for a specified amount of time. Afterward, it closes the valve and opens the next valve. Each station sends water to one zone, which typically consists of a group of sprinklers.
Automatic valves: Electrically operated valves that turn water on and off at signals from the controller. They are typically buried in valve boxes, several valves to a box.
Cool-season grasses: Grasses that thrive in northern areas, including Canada, and in high elevations in the South.
Compost: Humus made by decomposing vegetative matter in a compost bin or pile.
Crown: The part of a plant where the roots and stem meet, usually at soil level.
Cultivar: A cultivated variety of a plant, often bred for a desirable trait, such as pest- or disease-resistance.
Drainage: The movement of water through the soil. With good drainage, water disappears from a planting hole in less than a few hours. If water remains standing overnight, drainage is poor.
Drip irrigation: A low-pressure system for irrigating gardens, shrubs, and lawns. Water is released slowly over longer periods of time by emitters or sprayers, and it is applied as close to plant roots as possible. Typically used on the surface or just under the mulch of a garden bed, drip irrigation can be used underground to irrigate lawns.
Edging: A shallow trench or physical barrier of metal, wood, brick, or synthetic material used to define the border between lawn turf and another area, such as paving or a flower bed.
Endophytes: Fungi that live in some grasses (called endophytic), making them harmful or deadly to a variety of aboveground grass-eating insects.
Exposure: The intensity, duration, and variation in sun, wind, and temperature that characterize any particular lawn or planting site.
Frost heave, frost heaving: A disturbance or uplift of soil, pavement, or plants caused by moisture in the soil freezing and expanding.
Full shade: A site that receives no direct sun during the growing season.
Full sun: A site that receives at least eight hours of direct sun each day during the growing season.
Grade: The degree and direction of slope on an area of ground.
Ground cover: A plant, such as ivy, liriope, or juniper, used to cover the soil and form a continuous low mass of foliage. Often used as a substitute for turfgrass.
Hardiness: A plant's ability to survive the winter without protection from the cold.
Hardiness zone: A region where the coldest temperature in an average winter falls within a certain range, such as between 0° and -10°F.
Heat zone: A region determined by the average annual number of days its temperatures climb above 86°F.
Herbicide: A chemical used to loll plants. Preemergent herbicides are used to kill weed seeds as they sprout and thus to prevent weed growth. Post-emergent herbicides kill plants that are already growing.
Humus: Thoroughly decayed organic matter. Added to lawns, it will increase a soil's water-holding capacity, improve aeration, and support beneficial microbial life in the soil.
Invasive: A plant that spreads quickly, usually by runners, and mixes with or dominates adjacent plantings.
Landscape fabric: A synthetic fabric, usually water-permeable, that is spread under paths or mulch to serve as a weed barrier.
Lawn restoration: Improving a lawn without killing or removing all of the existing turf.
Lime, limestone: A white or grayish mineral compound used to combat soil acidity and to supply calcium for plant growth.
Loam: A soil consisting of a mixture of sand, silt, and clay that is ideal for growing.
Mass planting: Filling an area with one or a few kinds of plants, such as ground covers, spaced closely together. Often planted to create a bold, dramatic effector to reduce lawn maintenance.
Microclimate: Conditions of sun, shade, exposure, wind, drainage, and other factors that affect plant growth at any particular site.
Mowing strip: A row of bricks or paving stones set flush with the soil around the edge of a lawn area and wide enough to support the wheels on one side of a lawn mower.
Mulch: A layer of bark, peat moss, compost, shredded leaves, hay or straw, lawn clippings, gravel, paper, plastic, or other material spread over the soil around the base of plants. During the growing season, mulch can help retard evaporation, inhibit weeds, and moderate soil temperature. In the winter, a mulch of evergreen boughs, coarse hay, or leaves is used to protect plants from freezing.
Native: A plant that occurs naturally in a particular region and was not introduced from some other area.
Node: A joint in grass plants from which leaves emerge.
Nurse grasses: Annual grasses used to protect perennial grasses from excess wind and sun while they are becoming established.
Nutrients: Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, and other elements needed by growing plants and supplied by minerals and organic matter in soil and by fertilizers.
Organic matter: Plant and animal residues, such as leaves, trimmings, and manure, in various stages of decomposition.
Overseeding: Spreading seed over established turf that has been prepared for restoration.
Perennial grasses: Grasses that persist year after year, given the right conditions.
Plugs: Small round or square pieces of sod that can be planted to establish new lawns.
Pressure-treated lumber: Lumber treated with chemicals that protect it from decay.
Rain sensor: A device that sends a signal to the automated home sprinkler system's controller that rain is falling so that the controller will turn off and/or delay the restart of sprinklers.
Retaining wall: A wall built to stabilize a slope and keep soil from sliding or eroding downhill.
Rhizomes: Underground runners of some types of plants that extend laterally to create new plants.
Rotary sprinklers: Sprinklers, usually driven by gears, designed to cover large areas. They rotate across a preset arc, such as 90 degrees for placement in a corner, and deliver water in a sweeping motion.
Selective pruning: Using pruning shears to remove or cut back the branches of woody plants, usually to give the lawn greater sun exposure.
Sod: Carpet-like sheets of turf about 3/4 inch thick, 1 1/2 feet wide, and 6 feet long. Strips may be laid over prepared soil to establish new lawns.
Spray sprinklers: Sprinklers that produce sprays of various widths without rotation. They have shorter spraying radii than rotary heads and are consequently used for small areas, but they can deliver more gallons per minute.
Sprigs: Cut-up lengths of rhizomes or stolons that can be broadcast and pressed into the soil to establish new lawns.
Station: A group of sprinkler heads controlled by an automatic valve.
Stolons: Aboveground runners from which some grasses, particularly warm-season varieties, spread.
Subsoil: A light-colored soil layer usually found beneath the topsoil. It contains little or no humus.
Thatch: A mat-like buildup of grass roots and stems (but not of grass blade clippings) that if too thick can inhibit healthy growth.
Tillers: Aboveground sideshoots of some types of grass plants. Bunch grasses spread (enlarge) through growth of tillers.
Warm-season grasses: Grasses that grow best in southern regions, thriving in the heat of summer.
Watering program: The setting of a controller to know what days to water (called watering days), when to water (called a program start time), and how long to water (called station run time).
Weed: Any undesirable plant or grass species.
Zone: An area of lawn or planting within a landscape that requires similar amounts of water throughout.