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,


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



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



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



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

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


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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



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



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



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



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




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



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



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



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



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




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



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



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



Watering-in – Water applied to turf immediately after
the application of some pesticides

or fertilizers to dissolve and/or move materials into the



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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