Glossary of Turfgrass Terms


Aerification
Mechanical process by which air is returned to the soil. There are several different aerification methods, including core aerification, where hollow metal tines are used to remove a core of soil from the turf; solid tine aerification, where solid tines penetrate the soil and open holes, but do not remove soil plugs; and deep-time aerification, which are designed to penetrate more deeply into the soil than standard aerification methods.

Canopy
The outer most leaves of the turf.

Chlorophyll
The material that gives plants their green color and allows them to undergo photosynthesis.

Compaction
The process by which the pore spaces in soil are reduced by heavy traffic. Because there is less pore space in compacted soils, there is less oxygen. This results in weakened grass plants, turf thinning and excessively hard surfaces.

Cool-Season Grasses
Grasses that are best adapted to cooler times of the year, when temperatures range from 65 to 75°F. Cool-season grasses maintain their green color well into fall, and may remain green throughout the winter. Cool-season grasses include bluegrasses, ryegrasses, fescues and bentgrasses.

Cultivar
Short for "cultivated variety." Commonly used in the turf industry instead of the word "variety" to distinguish different types of grass. For example, Tifway 419 is a hybrid bermuda cultivar.

Cultivation
In the turf industry, cultivation refers to mechanical processes used to loosen the soil and reduce compaction and thatch, or to groom the surface.

Evapotranspiration
Measurement of the loss of water from the soil surface and from the plant. The use of evapotranspiration to determine irrigation needs is rapidly gaining acceptance in the turf industry.

Hydromulching
The process of establishing turf by spraying a mixture of seed, mulch, and fertlizer on the soil surface. The mulch helps protect the soil from erosion until the seed can take root.

Mulch
A wide variety of materials that will help the ground dry more slowly without interfering with plant growth.

Overseeding
The process of planting cool-season grass seed on top of a warm-season grass such as bermudagrass. The cool-season grass forms a temporary turf cover during the winter. Following a transition time in the spring, the cool-season grass dies as the warm-season grass emerges from dormancy.

Photosynthesis
The process by which plants, including grass, form the food material they need to function.

Plant Growth Regulators (PGRs)
Chemicals that can slow grass growth.

Plugging
The process of establishing turf by transplanting small pieces of sod in the soil at intermittent intervals.

Preemergence herbicides
Chemicals that kill germinating annual weed seeds and generally have little effect on perennial turf. Once a weed has germinated, preemergence herbicides will have little effect.

Rhizomes
Underground stems. Although they look like large, white roots, they are true stems just like stolons. The nodes on rhizomes are reproductive structures that can develop clones of the mother plant. Kentucky bluegrass is an example of a grass that produces only rhizomes. Bermuda and zoysia grasses produce both stolons and rhizomes.

Scalping
Scalping occurs when the mowing height is decreased so quickly that the turf cannot adapt to the change. In stress periods of summer, scalping can seriously damage or even kill turf.

Sodding
The process of transplanting established turf from one area to another.

Sprigging
The process of establishing turf by spreading grass stolons across the area to be established and working them into the soil.

Stolons
Aboveground stems which have nodes at various intervals, each of which has a bud which is a separate reproductive structure . These buds can develop new roots and new shoots that are clones of the mother plant. Creeping bentgrass and St. Augustine grass are examples of grasses that produce only stolons. Bermuda and zoysia grasses produce both stolons and rhizomes.

Syringing
Process of applying small amounts of water to wet the turf canopy. Syringing cools the turf through evaporation of water from the leaf surface, which can help turf survive during midday stress periods. Syringing also washes sugars, amino acids and other plant compounds extruded from the plant during stress periods from the surface of the leaf. Washing these materials from the leaf can be particularly useful in preventing high-temperature diseases such as Pythium blight from attacking the turf.

Thatch
The organic layer that develops above the soil and below the green tissue is called the the living grass canopy. Thatch is composed of a combination of dead organic debris and the living roots, crowns, and stems of the grass.

Tillers
New shoots of grass which emerge within the sheath tissue of the mother plant. Plants that develop exclusively by tillers are called bunch grasses . Perennial ryegrass is an example of a grass that produces tillers only.

Topdressing
The application of a thin layer of soil over the turf surface. Topdressing is one of the most important cultural practices that goes into the maintenance of high-quality turf.

Vertical mower
A machine with spinning vertical blades that can be set to just brush the surface of turf, or set deeper to pull up thatch.

Warm-Season Grasses
Grasses that are best adapted to warmer times of the year, when temperatures range from 80 to 95°F. Warm-season grasses typically go dormant when soil temperatures drop below 50°F. Warm-season grasses include bermudas, St. Augustines, zoysias, centipede, bahaigrass and carpetgrass.

Wilting
A symptom of inadequate irrigation. The turf will begin to take on a gray-green blue and will be slow to spring back when compressed by foot traffic.