GLOSSARY OF LAWN AND
GARDEN TERMS.
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Absorption (plant) - The entrance or taking-in of a chemical or nutrient into the plant.
Acid soil - Soil with pH less than 7.0. Raise soil pH (lower acidity and raise alkalinity)
by adding lime.
Acre - A measure of land totaling 43,560 square feet. A square acre is 208.75 feet on
each side.
Aerate - Loosen compacted soil to allow oxygen, water and nutrients to get below the surface.
Aeration is best done by removing plugs of soil from the lawn, rather than punching holes into the lawn.
Aerobic - The presence of air (oxygen) within an environment, in contrast to anaerobic conditions
which is the absence of oxygen.
Alkaline soil - Soil having a pH more than 7.0. Lower soil pH (raise acidity and lower alkalinity)
by adding sulfur.
Amendments - Organic substances added to the soil to improve moisture retention, oxygen level
and nutritional content.
Amine - A phenoxy herbicide formulation that is less prone to vaporizing and potentially moving
off-site than the ester form. Also see phenoxy herbicides, ester.
Anaerobic - The absence of air (or free oxygen) within an environment. See aerobic.
Analysis - Determination of (chemical) components by percentage of total weight.
Annual - A plant that germinates, grows, produces flowers and seeds, and dies within one
growing season.
Annual, summer - A plant that begins growth in the spring or early summer, thrives over summer,
flowers, produces seed and dies in the fall when the first frost occurs
Annual, winter - A plant that begins growth in the late fall and early spring, flowers,
produces seed and dies the following summer.
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Blade (leaf) - The flattened portion of the leaf projecting outward from the main shoot axis
and located above the sheath.
Blend (seed) - A combination of two or more varieties (cultivars) of a single turf grass species.
Broadcast application - Uniform distribution of a pesticide or fertilizer (or seed mix or blend)
over an entire area through a rotary type spreader.
Broadleaf - A term applied to non grass-like plants (dicots); often used in the context of weed control. Examples include dandelion and white clover.
Broadleaf herbicide - A weed killer designed to specifically kill broadleaf weeds without damaging
desirable turf.
Bulb - An underground modified stem, usually covered by a papery exterior. Bulbs are the growth
and food source for many flowering perennials.
Bunch-type growth - Plant development through the formation of clusters of tillers (shoots) at
or near the soil surface. Rhizomes or stolons are absent.
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Calibrating - The process of checking a mechanical applicator, such as a fertilizer spreader,
to insure that it will accurately deliver the right amount of material to the right amount of area.
Carbohydrate - Chemical compounds composed of carbon, hydrogen, and oxygen. Examples
include starch, sugar, and cellulose.
Chlorophyll - The green pigment in leaves. When present and healthy usually dominates all
other pigments.
Chlorosis - Absence of the green pigment chlorophyll from plant leaves usually due to environmental
or genetic factors.
Clay - Very fine soil particles. Clay soils (soils containing a high percentage of clay particles) are
often called heavy soils and are characterized by slow movement of water through the soil.
Clay soils can be improved with soil amendments such as manure, peat or mulch.
Clippings - Leaf blades and, in some cases, stems and sheaths, cut off by mowing. Decompose readily
due to their relatively high water content and generally simple chemical compounds.
Compaction (of soil) - Increase in soil density through destruction of its pore space, as by excessive
traffic or working the soil; especially impenetrable when dry.
Complete fertilizer - Any fertilizer product containing at least nitrogen, phosphorus, and potassium.
Complete metamorphosis - An insect life cycle going through the 4 distinct stages of egg, larva,
pupa and adult. The larva stages include several important turf grass pests associated with caterpillars,
grubs and maggots.
Compost - Partially to completely decomposed organic materials. It is typically made by piling a
mixture of grass clippings, leaves, etc., in a mound and, periodically stirring and mixing the pile
hastening the decomposition process.
Contact herbicide - A weed killer that kills primarily by contact with plant tissues.
Cool-season turf grass - Turf grass species whose growth is favored during the cooler portions
(60° - 75°F) of the growing season (spring and fall); may become dormant, injured or even
killed during hot, dry weather. Varieties include Kentucky bluegrass, perennial ryegrass, annual
ryegrass, tall fescue and the fine fescues.
Core Aeration (soil) - The mechanical removal of soil cores to improve soil air exchange,
water absorption and soil compaction. Cores are left on the lawn where they break down and
help increase microbial decomposition of dead organic material (thatch).
Crown - A tightly compressed stem-like structure or growing point that pushes new leaves
upward as they form and grow. In lawn grasses it is located at the base of the plant at or near
the soil line. The location of the crown allows regular mowing to be done while not compromising
the plants ability to re grow.
Cultivar - A group of cultivated plants distinguished by various features such as color, growth habit or
leaf form that, when reproduced through seed or vegetative means, retain their distinguishing features.
Cultivation - As applied to turf, cultivation means working the soil and/or thatch without destroying
the entire lawn surface; examples of cultivation include coring, slicing, spiking.
Cultural practices - Various horticultural methods and techniques used to care for plants in the yard
and garden. Examples include watering, fertilizing, mowing, weeding, and edging.
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Damage threshold level - The lowest amount of a pest population where unacceptable
levels of damage occur. Used to determine when, if any, pesticides are applied to control
a pest population.
Deciduous - A tree or shrub that loses all of its leaves at once, usually in the fall.
Decomposition - The rotting or decaying of an organic substance.
Disease - An interaction between a grass plant, pathogen and its environment that impairs
the normal function or development of a plant.
Disease Die off - Die off of turf due to a fungi that lawn is not able to overcome. Weather
conditions play a major roll causing this problem.
Dollar spot - Lawn disease that creates small patchy spotting in which the grass dies off,
ranges in color from tan to straw.
Dormant - A condition of significantly reduced activity where little if any growth occurs and
where rates of physiological activities, like photosynthesis, are minimal or non-existent.
Drip Line - The circle which would exist if you drew a line below the tips of the outer most
branches of a tree or plant.
Drought - Extended periods of dry weather often causing moderate to severe stress in turf.
It can be particularly damaging when combined with high temperatures.
Drought tolerance - The grass plant's ability to withstand extended periods of dry conditions
without incurring permanent damage. See also tolerance.
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Ecosystem (turf grass) - The interaction of a turf grass community with other plants, animals
and their surrounding environment.
Endophyte - A plant living and functioning within another plant. For example, a fungus. Turfgrass
cultivars are bred to include endophytes to discourage feeding
damage from certain insects.
Environment - The sum of all the physical, chemical and biological components to which
an organism is subjected. Soil, water, air, plants, animals, and human beings comprise the
environment to which turf grass communities are subjected.
Eradicate - To completely eliminate something from an area or the environment.
Erosion - The wearing away and transport of soil from land areas by wind or running water.
Ester - A phenoxy herbicide formulation that is more prone to vaporizing and potentially
moving off-site than the amine form. Also see phenoxy herbicides, amine.
Evaporation - Water loss back to the atmosphere through the vaporization of water.
Evapotranspiration (ET) - The combination of evaporation (water loss from land and water
surfaces) and transpiration (water loss from plants).
Evergreen - Plants that do not lose all of their leaves at once. Evergreens can be conifers or
broad-leaved.
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Fertilization/ Fertilizer - The application of nutrients to promote plant vitality. Organic or
inorganic plant foods which may be either liquid or granular used to amend the soil in order
to improve the quality or quantity of plant growth.
Fertilizer analysis - The amount of each nutrient (N-P-K) in a fertilizer container expressed
as percent of the total weight.
Fertilizer burn (foliar burn) - Plant injury (and usually death) caused by desiccation of tissue
due to contact with high concentrations of certain fertilizers.
Fibrous roots - Profusely branched roots consisting of many lateral rootlets and usually no main or
taproot development.
Field capacity - The point at which soil becomes saturated and cannot absorb any more water.
Foliar Feeding - Fertilizer applied in liquid form to the plants foliage in a fine spray.
Fungicide - A pesticide used to destroy or suppress fungi.
Fungus - (pl. fungi) A non-vascular (i.e., plants that do not contain water and nutrient
conducting vessels) plant that lacks chlorophyll. Some examples are: mushrooms, molds,
rusts, and yeasts.
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Germination - Sprouting of the root and shoot from a seed when environmental conditions
are favorable.
Granular - Pesticide or fertilizer formulations in which the active ingredient or nutrient is
attached to small, dry particles of some inert carrier such as clay or ground corn cobs.
Grass - A common name for members of the Grass (Gramineae) family of plants.
Groundcover - A horticultural term applied to low-growing vegetation covering the ground;
usually refers to broadleaf plants rather than lawn grasses.
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Hardpan - A layer of hard or compacted soil; impenetrable to plants roots, water and nutrients.
Herbicide - A substance used to kill plants. A herbicide can be selective (designed to kill a narrow
range of plants) or non-selective (designed to kill any plant it contacts). Herbicides can also be
pre-emergent or post-emergent.
High-maintenance lawn - Lawn areas composed of turf grass species and varieties requiring
higher levels of water, fertilizing and mowing to remain healthy.
Host plant - Any plant that provides nutrition (and possibly shelter) for a plant pest to survive.
That is, any plant that an insect or pathogen lives on is a host plant.
Hybrid - A cross between two plants of different variety, species or genus. Hybrids are usually
created to produce plants with specific characteristics, such as disease resistance, unique flower
color, etc.
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Infiltration rate - The rate at which water is absorbed into the soil. Clay soils have low infiltration
rates; sandy soils have high infiltration rates.
Inorganic (fertilizer) - Products used for supplying nutrients to a lawn; generally composed of
simple, mostly water soluble nutrient salts that are immediately available for plant use following
post-application watering.
Insecticide - A specific category of pesticides used for controlling insects.
Irrigation - The use of automated or manual systems for applying supplemental water for the
benefit of growing plants and replenishing soil moisture.
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Label - A printed statement attached to the pesticide or fertilizer container by the
manufacturer listing the contents, directions for use, and precautions. A pesticide
label is considered a legal document that is approved and registered by the U.S.
Environmental Protection Agency and the State Department of Agriculture.
Larva - The immature or worm stage (e.g., caterpillars, maggots, and grubs) of
an insect that goes through 4 distinct lifecycle stages (i.e., egg, larva, pupa, adult)
in its development. (See complete metamorphosis.)
Lawn - That portion of a yard or land area covered with grass plants kept short through
mowing.
Leaching - The downward movement in water of pesticides and/or nutrients through the soil column.
Ligule - a membranous or hairy appendage between the sheaf and blade of a grass leaf.
Lime – mineral that when applied, reduces acidic levels of soil (increases soil pH); pH 6.5
level is perfect.
Liquid fertilization - A method of applying plant nutrients as a solution of dissolved fertilizer salts.
Loam - A soil type composed of clay, silt and sand particles in relatively equal amounts. Loam
is considered ideal for plants because it drains well but does not dry out quickly.
Low toxicity - Term which the EPA uses for pesticides that have very low toxic levels.
Low-maintenance lawn - Lawn areas composed of turf grass species and varieties tolerant of
reduced levels of water, fertilizer and mowing while still remaining healthy.
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Metamorphosis - A basic change in form; for example, the changing of a grub to an
adult beetle or caterpillar into an adult butterfly.
Microbial - Effects associated with the action or influence of microorganisms.
Micro-nutrient - A nutrient required by plants in small or trace quantities. Does not
include the major plant nutrients (nitrogen, phosphorus and potassium).
Microorganisms - Living plants or animals (such as bacteria, fungi, or protozoa) that are
so small they can be seen only with the aid of a microscope.
Minerals - The inorganic materials that make up a portion of the soil derived from rocks;
they are usually of specific composition and crystalline in form.
Mowing - The periodic and usually regular cutting of a lawn area to a specified height for its
intended use and function. Accomplished with mowers, either manual or power operated.
Mulch - Non-living material used to cover the soil surface for purposes of controlling weeds,
conserving moisture, reducing soil temperatures, and in some instances, improving appearance.
Examples are wood chips, compost, and leaves.
Mulching mower - Mowers specifically designed to finely chop grass clippings and forcibly direct them back into the lawn leaving a clean, uniform appearance to the surface.
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Nitrogen - An essential nutrient required for plant growth. It is a significant component of
plant proteins. Adequate nitrogen produces good green color and vigorous plants. Shortages
of nitrogen are usually indicated by yellowing leaves and poor growth. Excess nitrogen can
result in unhealthy, lush growth making the plants more vulnerable to environmental stresses
such as heat, drought, frost and, increased disease susceptibility.
Non-selective - A term applied to a category of herbicides that does not discriminate in its
effect on one type of plant over another. For example, both grasses and broadleaf plants would
be injured or killed as opposed to selectively killing broadleaf plants without affecting the
grasses in a lawn area.
N-P-K - Chemical symbols for nitrogen (N), phosphorus (P) and potassium (K). On a container
of fertilizer, these nutrients are always expressed as percentages contained in the package and
are always shown in the order N-P-K.
Nutrient release rate - The speed at which plant nutrients, especially N, become available for
plant use following application to a lawn. This rate is often determined by the product, water
and temperature conditions at the time of application.
Nutrients (plant) - Mineral elements considered essential for plant growth. There are presently
16 minerals known to play essential roles in plant nutrition.
Nymph - The immature stage between the egg and adult of some insect groups; nymphs look
like the mature adult in form but do not have fully developed wings and are not able to reproduce.
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Organic - Chemical compounds containing the element carbon other than the inorganic
carbonates. Often refers to any part of, or anything produced by, plants or animals.
Organic matter (abbrev. OM) - Naturally occurring material such as manure, sewage
sludge, peat, grass clippings, etc. Organic matter is often used as a soil amendment.
Overseed or overseeding - The process of incorporating seed into an existing lawn
area for the purpose of lawn repair or introduction of different grass species.
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Pathogen (plant) - Usually applies to a microorganism with the capacity to cause a
plant disease.
Peat - A partly decomposed plant material found in marshy areas. Identification or
origination of parent plant material may still be possible (e.g., sphagnum peat moss).
Perennial - Plants that live two or more years producing flowers and seeds in successive
years.
Permanent wilting point - The point at which plant roots can no longer extract water from
the soil.
Pest (plant) - Any insect, mite, rodent, nematode, fungus, weed, or other organism capable
of causing plant stress, injury or death through disease, consumption of the plant or competition.
Pesticide - Any chemical (or mixture of chemicals) or biological agent used to control plant or
animal pests in order to protect and/or preserve desirable plants.
pH (soil) - A numerical measure of soil acidity or alkalinity based on the hydrogen ion (H+)
concentration in the soil. A pH of 7 indicates neutral conditions (neither acidic or alkaline);
above 7 is basic (alkaline), below 7 is acidic.
Phenoxy-type herbicides - A category of systemic weed killers that have a chemical structure
composed of six carbon atoms joined together in a ring formation. Two examples are 2,4-D
and mecoprop (MCPP).
Phosphorous - One of the major plant nutrients; important in root growth and plant energy
functions. The middle number of a fertilizer analysis N-P-K.
Photosynthesis - The chemical plant process where carbohydrates are formed by combining
carbon dioxide and water in the presence of light; occurs in the chlorophyll containing parts of
the plant (i.e., leaves and stems).
Pore space - Spaces within soil that contain air and water. Provides room for expansion of
fibrous roots. Sandy soils contain the most pore space: clay soils contain the least pore space.
Post-emergence - Generally refers to the application of an herbicide after the weed has emerged
(and is usually visible) from the soil.
Potassium - One of the major plant nutrients important in maintaining general plant health and
vigor. Often associated with improved stress and disease tolerance. It is the third number in the
fertilizer analysis N-P-K.
Pre-emergence - Generally refers to the application of an herbicide before the weed emerges
from the soil. Target plants are most often not visible above ground at the time of application.
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Quick-release nitrogen source - Nitrogen from these sources is available for use by the plant
as soon as water is applied and the fertilizer granule dissolves. Can also be applied in liquid
formulations. Plant responds with quick green-up and rapid rates of growth however, they
can result in lawn "burning" if they are over applied or if applied during excessive heat
without being watered in.
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Red thread - Lawn disease that causes blades to turn tannish brown with thin thready
attachment at the tips of the grass blade.
Renovation, turf - Improving a stand of turf through replanting into an existing lawn area.
May also include practices associated with rejuvenation.
Rhizomatous - A spreading growth habit resulting from the production and elongation of rhizomes.
Rhizome - An elongated underground stem with scale-like leaves and adventitious roots originating
from the nodes (bud containing areas along a stem).
Root - The fibrous, underground part of a plant associated with mineral and water absorption.
Root zone - That portion of the soil column occupied by plant roots.
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Sand - Large soil particles. Sandy soils (soils containing a high percentage of sand particles)
are characterized by rapid water movement through the soil. Sandy soils can be improved
with soil amendments such as manure, peat or mulch.
Scalping - An undesirable mowing practice that removes an excessive amount of green
leaves and shoots at any one mowing. It can seriously weaken or even kill the turf grass.
Selective - The term usually applied to an herbicide that has the ability to only destroy one
type of plant while not affecting others. For example, a post emergence, broadleaf herbicide
will kill broadleaf plants (such as dandelions) in the lawn without affecting the grass plants.
Shade - An area of reduced light quantity (and often quality) resulting from the partial or
complete obstruction of direct sunlight.
Sheath - The tube shaped, basal section of the grass leaf enclosing the stem.
Shoot - Above ground, vertically oriented growth giving rise to both leafy growth and
flowering stems.
Shoot density - The number of shoots contained in a specified area of lawn.
Silt - Soil particles that are larger than clay and smaller than sand.
Slit-seeding - The use of a machine known as a slit-seeder to seed a new lawn area or
overseed an existing area. Slit-seeders utilize a series of vertically rotating blades to cut
small grooves into the soil for improved seed-to-soil contact.
Slow-release nitrogen source - Nitrogen from these sources becomes available as the
product is broken down by soil microbes and/or chemical action. Plant responds with a
slightly slower rate of green-up and growth. Usually this is a desirable characteristic.
Sod - Squares or strips (rolls) of turf grass cut from a production field and usually with a
thin layer of soil still attached that is used for vegetatively installing a turf grass area.
Soil - The earth's thin upper layer capable of supporting plant growth. It is characterized
by such things as texture, structure, color, and fertility which distinguish it from material
like gravel, sand or bedrock that also cover a portion of the earth's surface.
Soil structure - The combining of microscopic soil particles through the action of soil
microbes into larger units commonly known as soil granules, crumbs or aggregates.
Loose, crumbly soil structure is a must to sustain health plant growth.
Soil test - A scientific analysis of a soil sample that determines its pH, texture, organic
matter content and various degrees of chemical composition. They are used to assess a
soil's suitability for particular uses and any necessary modifications to prepare it for the
intended use.
Soluble (fertilizer) - Fertilizers that are made up of easily dissolved components in water
which are immediately available for plant use; they can result in lawn "burning" more
easily that slow-release fertilizers. (See quick-release nitrogen source)
Spot treatment - Generally refers to the application of a pesticide to a limited or small area.
In the case of herbicides, it may also be applied to the treating of individual plants or infested areas.
Stem - The horizontal or vertical axis of a plant supporting leaves, buds and flowers.
Stolon - An elongated stem growing along the ground surface and giving rise to leaves and
adventitious roots at the nodes (bud containing areas along a stem).
Stoloniferous: - spreading growth habit resulting from the production and elongation of stolons.
Stress (plant) - Usually applied to environmental factors restricting normal or healthy plant
growth. Some of these factors are heat, drought, compacted soils, traffic, water logging and cold.
Summer Patch - Lawn disease that appears as green growth in the middle of dead brown patches
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Thatch - A dense, fibrous layer of living and dead grass stems, leaves, and roots, un decomposed
or partially decomposed, that accumulates between the green vegetation and soil surface.
Tiller - A lateral shoot, usually erect, that develops from axillary buds in the crown.
Tolerance - The plant's ability to withstand stresses associated with unfavorable environmental
conditions or the application of pesticides.
Topsoil - The upper portion of soil that is generally higher in organic matter in comparison to the
subsoil and usually has more favorable characteristics of soil fertility, aeration and structure.
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Urea - A quick-release nitrogen fertilizer source. Usually available as 45-0-0 or 46-0-0.
It is also described as a synthetic organic fertilizer as it contains the element carbon in
its chemical structure.
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Vigor (plant) - The combination of genetic and environmental factors that determine the
rate and amount that a turf grass species or cultivar is able to grow and spread.
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Warm-season turf grass - Turf grass species whose optimum growth occurs during the
warmer periods (80° - 95° F) of the growing season. Varieties include Bermuda grass,
Zoysia grass, St. Augustine grass grown in the Southern states.
Watering-in - Water applied to turf immediately after the application of some pesticides
or fertilizers to dissolve and/or move materials into the soil.
Weed - An undesired, uncultivated plant growing in a manner so as to adversely compete
with desirable plants for water, light and nutrients, or destroy aesthetic qualities of a lawn.
Winterizer - specially combined fertilizer to give turf proper nutrients before going dormant
for the winter.
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