Glossary of Turfgrass Terms.


Acidity (acid soil):   a soil condition which has a pH below 7.0.

Active ingredient:    the portion of a product responsible for its activity.

Aerification:   the process of improving the movement of air, water and nutrients into the soil by removing thatch, slicing the soil or removing plugs of soil.

Agronomy:   the theory, study and practice of field-crop production and soil management.

Algae:   microscopic plants generally found growing on the soil surface in areas of poor sunlight, poor drainage, or low fertility.

Alkalinity (alkaline soil):   a soil condition which has a pH above 7.0.

Alternate:   an orderly growth with a leaf or seed arranged on one side and then the other, along a stem or spike.

Ammoniacal:   an immediate release source of nitrogen used in some fertilizers

Analysis (product):    the statement on a package listing the ingredients and their percentages by weight.

Annual:   any plant which germinates, matures, produces seed and dies within one growing season.

Asexual:   without sex. Propagation by sod, stolons or offshoots.

Auricles:    projecting arms of a grass leaf, located at the collar, which may or may not clasp the stem.

Axil:     the point where the leaf grows from the stem.


Bahiagrass:   a coarse-textured, warm season grass which spreads by tillers and some rhizomes.

Barrier:   a chemical boundary located below the soil surface to prevent the germination or growth of undesirable plants.

Bentgrass:   a cool season grass of fine to medium texture with stoloniferous growth.

Bermudagrass:   a fine to medium-textured grass which forms a turf due to vigorous rhizomes and stolons.

Biennial:   a plant which completes its life cycle in two years. Forms as rosettes the first season, and produces flowers and seeds the second.

Blade:    the wide or expanded part of a grass leaf extending from the sheath.

Blight:   rapid discoloration and death of tissues, especially leaves, leaf sheaths and stems—with no definite pattern.

Blind seed disease:    a disease affecting turfgrasses grown for seed that causes a reduction in germination percentages.

Bluegrass:   a cool season grass of medium-fine texture, reproducing vegetatively by rhizomes and tillers.

Broad leaved:   referring to dicot plants.

Bud:   the undeveloped state of a stem or flower generally covered with overlapping leaves.

Bulb:     a thickened or fleshy underground stem usually made up of overlapping, foodstoring scales.


Calcium carbonate equivalent:     refers to the number of pounds of calcium carbonate (CaCO3) required to neutralize a ton of fertilizer.

Calibrate:   measure rate of application of a spreader under defined conditions.

Capillary Action:   movement of water and nutrients between soil particles and between the cells of any organism.

Capsule:   a closed receptacle, containing seeds, composed of two or more parts.

Carrier:   the material added to a product to facilitate its distribution.

Centipedegrass:    a coarse-textured, stoloniferous grass which grows best on acid soil.

Certified seed:   seed grown under inspection by a certifying agency and when mature, approved as to its genetic identity, purity and high quality standards.

Chaff:   the husks of grain or other waste material separated from pure seed during cleaning.

Chlorophyll:   the green pigment in plants which is vital for photosynthesis.

Chlorosis:   the result of poor chlorophyll production in green plants which causes a yellowish color.

Clay soil:   indicates a soil type consisting primarily of clay —% to 3A of the content.

Clone:     hopeful new grass varieties being grown in the field for the purpose of producing enough seed to last the duration of the testing program.

Clusters:   the grouping of flowers or leaves on a plant.

Collar:   a narrow band marking the place where the blade and the sheath join.

Compacted soil:     a condition where the soil particles are packed tightly together forcing out all air and moisture.

Compost:   a decomposed mixture of plant and animal waste to which lime, fertilizer or soil may have been added.

Contact herbicide:   a herbicide that kills weeds by direct contact rather than by translocation.

Contaminant:   any undesirable plant in turf or undesirable seeds in a blend.

Contour:     the grade or slope of a turf area or land surface.

Control:   to limit population and spread of a pest to tolerable levels.

Conversion:   gradually changing an old turf into turf of a more desirable grass without total renovation.

Cotyledon:   the first leaf, or leaves, that emerge from the seed plant.

Crop:   a term used on a seed label —meaning any plant grown for profit.

Crown:   the above ground base of a grass plant from which all growth begins.

Culm:   the stem of grasses and sedges.

Cultivar:   a variety of plants, which retain their distinguishing features when reproduced.

Cultivate:  preparing the soil for seeding.


Debris:   the accumulation of unwanted material in turf or seed bed.

Decay (decompose):   the breakdown of living matter into chemical forms.

Denitrification:   the biochemical reduction of nitrogen in the nitrate or nitrite forms to elemental nitrogen.

Density:  the thickness of turf measured by the number of plants in a given area.

Desiccation:   the drying out of turf—usually used in reference to "winter desiccation" when there is lack of snow cover to protect the turf from drying winds.

Dichondra:   a vining, broadleaf plant which is used successfully as a ground cover in California.

Dicot (dicotyledon):   a plant emerging from the seed with two leaves.

Disease:   a condition caused by parasitic organisms, resulting in damage to the grass plant.

Disease organism:    the parasite (usually a fungus) which causes injurious effects to the grass plant.

Disease tolerance:    the ability of a plant to resist a disease.

Dormant:   a reduction of growth and other normal life functions of perennial plants caused by stress or seasonal changes.

Dry wilt:   a condition caused by lack of moisture in the soil.

Duff:   an organic layer consisting of partially decomposed vegetative matter such as leaves, roots, stems and stolons.


Ecology:   the study of the inter-relationships of organisms to one another and to the environment.

Environment:   all the external conditions which affect the growth of an organism.

Epidemic:   a disease outbreak among a population at one time.

Epidermis:   the outermost layer of cells or tissue of a plant.

Ergot:   a disease affecting the flowering parts of seed production turfgrasses, causing large reductions in seed yield.

Erosion:  the wearing away of the soil by wind, water or ice.

Eutrophication:  a condition occurring in bodies of water where the plant is deficient in oxygen and aquatic plants-are abundant. This process is accelerated by the surface runoff of nutrients such as nitrogen and phosphorus.

Evaporation:   the process by which a liquid is changed to a vapor or gaseous form.

Evapotranspiration:   water transpired by plants plus that which has evaporated from the soil.


Field capacity:   the remaining water content of a soil after it has saturated and drained for a specific length of time.

Fertilizer:   any material or mixture which supplies the necessary plant nutrients, usually nitrogen, phosphorus and potash.

Fertilizer analysis:   the percentage by weight of the components found in a fertilizer. For example, a fertilizer with a 10-6-4 analysis contains 10 percent nitrogen (N), 6 percent phosphoric acid (P2O5) and 4 percent potash (K2O).

Fertilizer grade:  the guaranteed minimum analysis of the major nutrients found in fertilizer

Fertilizer ratio:   a ratio of the basic weights of the major nutrients found in a fertilizer. For example, a fertilizer having an analysis of 18-6-6 would have a 3:1:1 ratio or 3 parts of N to 1 part of P and 1 part of K.

Fescue:   cool season grasses of fine and coarse textures reproducing vegetatively by tillers or rhizomes.

Foliage:   the leaf covering of a plant.

Fructification:   production of spores by fungi.

Fungi:   plants lacking chlorophyll that cannot produce their own food; parasitic forms cause turf diseases.

Fungicide:   any chemical which controls or destroys the growth of a fungus.


Germination:    the beginning of visible growth of a plant as it emerges from the seed.

Ground cover:  a low-growing plant used in place of turf—example: dichondra, ice plant, ivy.

Grub:   the larva stage of various beetles; one of the insect invaders of turf

Guard cells:   a pair of cells which regulate the opening and closing of the stoma.


Habit (growth):   the general pattern of style of plant growth.

Habitat:    the environment which supplies the needs for plant or animal life.

Herbicide:    a chemical used to destroy or inhibit plant growth.

Hermaphrodic:   reproduction by one individual containing both functional male and female reproductive organs.

Heterogeneous:   refers to having unlike qualities or differing in kind.

Homogeneous:   consisting of similar parts orelements.

Humus:   decomposed organic matter.

Hybrid:   a plant produced by the crossing of two species with different characteristics.

Hygroscopic (water):   water held so tightly by soil particles that it is unavailable to plants

Hyperplasia:   overgrowth due to increased cell division.

Hypertrophy:   overgrowth due to abnormal cell enlargement.

Hyphae:   threads of fungal growth.


Impregnate:   to force particles of one substance between the particles of another.

Inert:   any substance which does not take an active part in a chemical reaction or anything in a seed blend that will not grow.

Infection:   the process of gaining entrance and becoming a parasite within a host plant.

Infestation:   the spread of harmful weeds, diseases or insects in a lawn,

Inflorescence:    the flower cluster of a plant and its mode of arrangement.

Inorganic:   natural or synthetic elements or chemicals of non-living material.

Insecticide:   any chemical which destroys insects.

Insoluble:   any substance which cannot be dissolved by a given liquid.

Internode:   the portion of a stem or other plant parts between two nodes.

Irregular:   an arrangement of leaves, stems or seeds which have no pattern or uniform order.


Larva:    the immature, wormlike stage of insect development.

Lateral growth:   the sideward rather than upward growth of a plant or leaves.

L.D.:   means the lethal dose of a pesticide. An LD50 indicates a lethal dose that will kill 50 percent of a given population of test animals under stated conditions.

Leaching:   the removal of materials in solution by the passage of water through soil.

Leaf:   the lateral outgrowth of a stem.

Lesion:   a scar or mark on a plant caused by a disease or injury.

Ligule:   an upright projection of tissue at the junction of the blade and sheath of a grass leaf

Lime:   Lime generally refers to calcium oxide (CaO). There is a variety of materials which composes the various types of limes. The most commonly used forms of lime are ground limestone (carbonates), hydrated lime (hydroxides) and burnt lime (oxides).

Loam:   a soil which is made up of sand, silt and clay.

Lobe:   a rounded or divided segment of a leaf.


Maintenance:   the upkeep or care of turf.

Margin:   the edge or border of a leaf or blade.

Mature:   the state of full development.

Membranous:   a substance which is thin, soft, pliable and often transparent or translucent.

Methylene ureas:   a ureaformaldehyde resin whose structural characteristics control the solubility of nitrogen and therefore its rate of release.

Microorganism:   any of a range of small-sized organisms ranging from protozoa and bacteria to fungi.

Midrib (midvein):   the central or main rib or vein of a leaf.

Monocot (monocotyledon):    any plant emerging from the seed with only one leaf.

Moss:   a low-growing, simple plant found in shady, moist areas or turf, generally lacking in sunlight, drainage and fertility.

Mulch:   a covering, such as straw, used to protect seedlings, preserve moisture and prevent erosion.

Mutation:   a genetic change in an offspring which results in distinct permanent characteristics which differ from those of the parent.

Mycelium:   the mass of interwoven, threadlike filaments of a fungus growing in and among grass blades.


NAI index:   nitrogen availability index. It is the percentage of water insoluble nitrogen which becomes available to the plant in 1-4 weeks. The higher the NAI index implies a more rapid release of nitrogen.

Net venation:   the veins of a broadleaf plant branching in all directions to form a net-like pattern.

Nitrification:   the soil process by which nitrites are changed to nitrates through the aid of bacteria.

Nitrogen (N):   one of the three major nutrients necessary for healthy plant growth. Used by the plant for chlorophyll production and plant and leaf growth.

Node:   the joint where the leaf is attached to the stem.

Noxious weed:   any plant which has been declared by law to be a harmful or dangerous weed.

Nutlet:   a small, reproductive growth on the roots of sedges and other plants,

Nutrient:    any food or plant material that nourishes or promotes plant growth,

Nymph:   the immature stage in the life cycle of certain insects.


Open field burning:    traditional method of sterilizing seed production fields by burning the top growth and thereby stimulating next year's regrowth.

Opposite:   two leaves at a node growing across from one another.

Organic:   any substance formed from decayed living matter.

Osmosis:   an interchange of materials between two solutions which are separated by a semipermeable membrane.

Overseed:   seeding into a thin, existing turf.


Panicle:   an irregularly branched and rebranched inflorescence.

Parallel venation:   principal veins of a leaf parallel to each other and to the longitudinal axis of the leaf.

Parasite:   an organism which takes its food from the living tissues of a host organism.

Parthenogenesis:   reproduction by eggs without fertilization by sperm.

Pathogen:   an organism causing a disease.

Peat:  partially decomposed organic matter entering the first stage of coal formation.

Percolation: the movement of water through the soil. 

Pesticide:   any chemical agent used to control pests. This would include fungicides, herbicides, insecticides, nematocides, etc.

Petiole:  the stalk which supports the leaf.

PH:   means "potential Hydrogen" and is used to determine the acidity or alkalinity of the soil.

Phloem:   conducting tissue to the outside of a vascular bundle, notably active in moving organic compounds to regions of low concentration.

Phosphorous(P2O5):   one of the three major plant nutrients necessary for healthy growth. Used in root growth, plant development and seed formation.

Photosynthesis:   the process by which plants containing chlorophyll convert sunlight, carbon dioxide and water into chemical energy for their own use.

Plugging:   a method of starting a turf area by inserting small cores of grasses at given intervals.

Post-emergence control:   applying a herbicide which destroys a growing plant.

Potash (K2O):   one of the three major plant nutrients necessary for healthy growth. Used for the overall growth.

Pre-emergence control:   applying a herbicide which prevents germination or growth of a plant.

Prostrate:   lying flat upon the ground.

Protoplasm:   the life-giving substance of all organisms.

Pubescence:   having a covering of soft, fine hairs.

Pupa:   the intermediate stage of insect development between the larva and adult.

Purity:   the percent, by weight, of pure seed of each component in the blend.

Pustules:  a small blister-like elevation found on grass blades and generally associated with fungi.


Renovate:  to rebuild a turf using an existing turf as the seedbed.

Residual:   the length of time a chemical remains effective after an application.

Resilience:  the ability of a grass blade to return to an upright position after bending.

Respiration:   a process by which living plants and animals use oxygen for metabolism. This is often mistaken for inhaling or the breathing of oxygen.

Rhizome (rootstock):   the underground stem which is capable of producing a new plant. 

Roguing:  the manual process of selectively removing off-breed plant types from seed production fields.

Root system:   the underground downward growth of a plant; anchors plant to the soil and absorbs moisture and nutrients from the soil for use by the entire plant.

Root zone:    the area of the soil where roots develop, grow and mature.

Rosette:  a plant having a circular cluster of leaves.

Ryegrass:   annual or perennial types of cool season grasses of fine and coarse textures.


St. Augustine:  a coarse-textured, warm season grass which spreads by stolons

Salt tolerance:   the ability of a plant to withstand salt water or salt-laden soil.

Sandy soil:   a broad term used to indicate a soil type with the major part being 2/3 to 3/4 sand.

Saprophyte:   an organism which lives on a host without taking food from the plant.

Saturation:   a condition when the soil is holding its total capacity of water.

Scalp:  to cut the turf from the soil, or to mow overly close, or to cut into the grass crowns.

Sclerotia:   a hard, dense, compact mass of mycelium with a specialized outer coat or rind that contains spores in over-summer or over-winter periods.

Sedge:   a family of plants resembling grass, but having a solid triangular stem.

Seed:   the reproductive structure of a plant containing the embryo (young plant), food supply and protective coat.

Seed bed:   soil that is properly tilled and prepared for seeding.

Seed coat:   the outer layer of the seed structure which holds the embryo and food supply and protects the young plant until germination.

Seed count:   the number of seeds in a pound.

Seedpod:   a dried case or capsule containing a seed or seeds.

Segmented body:   the body of an insect which is divided into several distinct parts.

Selective herbicide:  a weed killer capable of controlling one type of weeds without damaging other types of plants.

Serrated:   the saw-toothed pattern on the margin of a leaf.

Sessile:    a condition where a plant has flowers or leaves without a stalk.

Shattering:   the dropping of seeds from a seed head due to over ripening in the production field.

Sheath:  the tubular lower portion of a grass leaf which surrounds the stem.

Silt:   a finely textured soil or sediment usually deposited by water

Sod:   the grass covered surface of the ground.

Soil:   the natural medium for plant growth, usually containing inorganic and organic materials.

Soil amendments:   any material added and worked into the soil to improve productivity.

Soil porosity:   describes the availability of pores or cavities for nutrient and moisture storage.

Soil sterilant:   a chemical which will destroy all vegetation and seeds in the soil.

Soluble:   capable of being dissolved by a given liquid.

Solution:   a liquid containing a dissolved substance.

Spatulate:   a leaf which gradually widens from the base to a rounded end, resembling a spatula.

Species:   a class of organisms having common characteristics designated by a common name.

Spike:   an inflorescence on which the flowers or seeds are sessile and are arranged on any unbranched stem.

Spore:   the reproductive structure of a fungus functioning as a seed.

Spray drift:   the movement of airborne spray particles from the spray nozzle outside the intended contact area.

Sprigging:   establishing new turf by planting stolons in the soil.

Stand:   a group of plants growing together in one area.

Stem:   the part of a plant which develops buds and shoots and supports a leaf or flower

Stolon (runners):   a stem growing along the soil surface which is capable of taking root and starting a new plant at each node.

Stoloniferous (creeping):   the spreading of plants by stolons.

Stomata:   minute openings for transpiration on the surface of leaves and stems, which are opened and closed by guard cells.

Stress:   a condition under which a plant suffers due to lack of moisture, food, extreme heat, or any combination of the three.

Stromata:   a cushion-like, mycelial mass of tissue on or in which fructification usually occurs.

Sub-irrigation:   supplying moisture to the root zone from beneath the surface.

Subsoil:   the stratum of weathered material that underlies the surface soil.

Surfactant:   a material that improves the emulsifying, spreading, wetting and other surface modifying properties of chemical formulations.

Swathing:   the process of cutting the seed heads in the seed production fields and laying them into windrows before combining.

Symptom:   a change or conditions indicating the existence of disease, injury, etc.

Synthetic:   any material created by artificial means.

Syringing:   adding moisture to a plant through the leaf to reduce or prevent water loss and cool the plant.

Systemic pesticide:   a chemical which is absorbed by the plant roots, and thus, internally prevents disease or insect damage.


Taproot:   a long, single, vertical-growing root.

Tensiometer:   instrument used for measuring the pressure of soil water.

Terminal:   the end of a branch or stem.

Thatch:   the accumulated layer of undecomposed plant parts between the living plant parts and the soil surface.

Tillers:   a sprout or stalk that forms its own leaves and originates at the base of the parent plant.

Tolerance:   degree to which a plant endures a stress.

Top dressing:   a prepared mixture spread over, and worked into the turf. It is apt to be formulated of sand, compost, organic matter and fertilizer.

Topsoil:   the upper layer of soil, which ideally, contains rich, fertile, organic matter.

Trace elements:   small amounts of certain elements essential for healthy plant growth.

Translocate:   to move about in the plant in solution.

Transpiration:   the exchange of gases and water vapor between the plant and the atmosphere.

Turf:   the upper stratum of soil bound by grass and plant roots into a thick mat.

Turgidity:   the expansive force in a blade, caused by the presence of water, permitting it to stand erect.

Urea:   a water soluble nitrogen compound, used in fertilizers, made from carbon dioxide and ammonia.


Vascular system:   transports the nutrients and water to all parts of the plant.

Veins:   part of the vascular system which forms the framework of the leaf.

Venation:   the arrangement of the veins in a leaf.

Vermiculite:   a micaceous mineral silicate which expands with heat and has absorption qualities.

Vertical mowing:   cutting perpendicular into the turf to lift or cut stolons to control grain, or to remove thatch.

Viable:   a seed which is capable of germinating.

Vining:   plants whose stems creep along the surface of the ground.

Volatilize:   the state of changing from a liquid to a gas at ordinary temperatures when exposed to the air.


Weed:   any plant growing where it is not wanted.

Wet wilt:   the inability of a plant to absorb enough moisture through the roots to equal the rapid loss of moisture through the leaves.

Whorl:   a circular arrangement of three or more leaves or flowers around a single plant.

Winterkill:   injuries of turf resulting from environmental stresses during the cold part of the year.


Xylem:   the inner conducting layer of a bundle, through which bulk water is removed.

Zoysia:   a warm season grass which spreads slowly by stolons and rhizomes.