List of Abbreviations and Definitions


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This list was provided by the Grow Support Team.

A List of Abbreviations and Definitions

(24/7) 24 hours of light 7 days a week
(18/6) 18 hours of light 6 hours of total darkness
(12/12) 12 hours of light 12 hours of darkness
(BEANS) Seeds
(CA) Calcium
(CFL) Compact fluorescent lighting
(CFM) Cubic feet per minute
(CO2) Carbon Dioxide
(CRI) Color Rendering Index
(FERTS) Fertilizer
(FLOROS) Florescent lights
(GERM) Germination
(HID) High intensity discharge
(HPS) High-pressure sodium
(LED) light emitting diode
(LST) Low stress training
(MG) Magnesium
(MH) Metal Halide
(NFT) Nutrient Film Technique
(NPK) Nitrogen/Phosphorus/Potassium
(NUTES) Nutrients
(PH) potential of Hydrogen
(PPM) Parts per million
(RES) Reservoir
(RO) Reverse Osmosis
(SCROG) Screen of Green
(SOG) Sea of Green
(TEMP) Temperature
(VEG) Vegetating

- A -
ACID – an acidic solution has a pH below 7
AERATION – directly supplying roots and grow medium with air or oxygen
ALGAE – any of various chiefly aquatic, eukaryotic, photosynthetic organisms, ranging in size from single-celled forms to the giant kelp
ALKALINE – a term describing a grow medium or nutrient solution with a high pH (over 7)
AMPERE (AMP) – this is the unit used to measure strength of an electric current
- B -
BACTERIA – any of the unicellular prokaryotic microorganisms of the class Schizomycetes, which vary in terms of morphology, oxygen and nutritional requirements, and motility, and may be free-living, saprophytic, or pathogenic in plants or animals
BALLAST – a device used to regulate flow of electricity to match the needs of a specific bulb
BLOOM – (1) the flower of a plant (2) the action of a plant’s flower reaching maturity
BLOSSOM BOOSTER – a fertilizer with a high phosphorous rating which increases flower yield
BOLT – a plant which has gone to seed prematurely
BUD – a small protuberance on a stem or branch, sometimes enclosed in protective scales and containing an undeveloped shoot, leaf, or flower
BURN – leaf tips which turn noticeably dark from excess fertilizers or salts
- C -
CANOPY – the uppermost reaches of your crop; those leaves most readily available to the light source
CARBON DIOXIDE (CO2) – a colourless, odourless, tasteless gas in the air necessary for plant life. It occurs naturally in the atmosphere at .03%
CELL DIVISION – The process by which a cell divides to form two daughter cells. Upon completion of the process, each daughter cell contains the same genetic material as the original cell and roughly half of its cytoplasm
CHITIN – a tough, protective, semitransparent substance, primarily a nitrogen-containing polysaccharide, forming the principal component of arthropod exoskeletons and the cell walls of certain fungi
CHLOROSIS – a sick plant displaying yellowing leaves due to a sub standard chlorophyll process; commonly caused by nutrient deficiency or imbalanced pH
CLONE – a plant which has been produced through asexual reproduction (i.e. – cuttings, layerings, and tissue culture)
CONDITIONING – the method used to bring an inert growing medium to optimum pH levels, such as soaking new rockwool in an acidic solution to lower the pH from 8.0 to 5.5
COTYLEDON – a leaf of the embryo of a seed plant, which upon germination either remains in the seed or emerges, enlarges, and becomes green. Also called seed leaf
CULTIVATION – the act of processing the fruit of a mature plant
CYTOKININ – any of a class of plant hormones that promote cell division and growth and delay the senescence of leaves
- D -
DAMPING OFF FUNGUS – disease which attacks young seedlings and cuttings causing them to rot at the base. This is generally caused by over watering.
DISSOLVED SOLIDS – the amount of dissolved solids, usually fertilizer salts, that are measured in parts per million
DRIP SYSTEM – an efficient water delivery system which employs a plumbed main hose filtering nutrient through various drip emitters, one drop at a time.
- E -
ELECTRICAL CONDUCTIVITY – the ability of a solution to carry electrical energy as a result of the elements and compounds in the solution
- F -
FERTILIZER – see nutrient
FLOOD TABLE – a large flat, walled basin used to hold and support grow medium and plants. Nutrient is then flooded into the basin at regular intervals
FOLIAR FEEDING – using a mister or spray bottle to deliver fertilizer solution directly to the foliage
FUNGICIDE – a product which destroys or inhibits fungus
FUNGUS GNATS – minute, blackish, gregarious flies destructive to mushrooms and seedlings
- G -
GERMINATION – the process of causing the initiation of a plant from seed
GRAFTING –uniting (a shoot or bud) with a growing plant by insertion or by placing in close contact
GROW MEDIA / MEDIUM – the material used to support a plant’s root system and store nutrient solution in a hydroponic garden
GUANO – a substance composed chiefly of the dung of sea birds or bats, accumulated along certain coastal areas or in caves and used as fertilizer
- H -
HALOGEN – any of the elements chlorine, bromine, iodine and astatine existing in a free state. Halogens are in the arc tube of a halide lamp
HARDEN OFF – to gradually acclimatize a plant to a harsher environment. A seedling must be hardened off before planting outdoors
HID – High Intensity Discharge. This generally applies to the light bulbs used in hydroponic gardens
HOOD – the reflective cover of an HID lamp
HOR – abbreviation for Horizontal. This is commonly stamped on some HID bulbs to provide instructions as to how they should be mounted
HORMONE – chemical substance that controls the growth and development of a plant
HUMIDITY – wetness in the atmosphere
HUMUS – a brown or black organic substance consisting of partially or wholly decayed vegetable or animal matter that provides nutrients for plants and increases the ability of soil to retain water
HYBRID – an offspring created by combining two plants of different breeds, variety or genetic make-up
HYDRATED LIME – instantly soluble lime, used to raise or lower pH
HYDROPONICS – cultivation of plants in nutrient solution rather than in soil
HYGROMETER – instrument used to measure the relative humidity in the atmosphere
- I -
INTENSITY – the magnitude of light energy per unit. Intensity diminishes as light travels away from the source
- K -
KILOWATT-HOUR – the measure of electricity used per hour. Ex: a 1000 watt HID uses one kilowatt per hour
- L -
LEAF CURL – leaf malformation indicative of over watering, over-fertilizing, lack of magnesium, insect damage, fungus damage or negative tropism
LIGHT METER – a device used to calculate and measure the effective light in a tested area
LIGHT MOVER – an apparatus designed to simulate a natural horizon by slowly changing the position of a lamp and its influence
LUMEN – measurement of light output. One lumen is equal to the amount of light emitted by one candle that falls on one square foot of surface located one foot away from the candle
- M -
MACRO-NUTRIENT – one or all of the primary nutrients N-P-K or the secondary nutrients magnesium and calcium
MAXIMUM YIELD MAGAZINE – the number one source for the latest information pertaining to the hydroponics industry
MICRO-NUTRIENT – also referred to as trace elements, which includes the minerals S, Fe, Mn B, Mb, An and Cu
MICROBIAL – a minute life form; a microorganism, especially a bacterium that causes disease
MODULAR HYDROPONICS – the method of growing plants hydroponically in which each individual plant has its own contained grow medium and structure
MONOCHROMATIC – producing only one colour
- N -
NEMATODE – unsegmented worms with elongated rounded bodies pointed at both ends; mostly free-living but some are parasitic
NFT – Nutrient Film Technique. Nutrient is fed into grow tubes where the roots draw it up. A thin film of nutrient allows the roots to have constant contact with the nutrient and the air layer above at the same time
NITROGEN (N) – a nonmetallic element that constitutes nearly four-fifths of the air by volume, occurring as a colorless, odorless, almost inert diatomic gas, N2, in various minerals and in all proteins and used in a wide variety of important manufactures, including ammonia, nitric acid, TNT, and fertilizers. Atomic number 7; atomic weight 14.0067; melting point -209.86°C; boiling point -195.8°C; valence 3, 5
NUTRIENT – plant food, essential elements N-P-K, secondary elements and trace elements which are fundamental to sustaining plant life
NUTRIENT DEFICIENCIES – low and improper levels of nutrient being supplied to a plant
- O -
ORGANIC – of, marked by, or involving the use of fertilizers or pesticides that are strictly of animal or vegetable origin
- P -
pH – a scale from 1 to 14 that measures acid to alkaline balance.
PARABOLIC REFLECTOR – a concave reflector with a series of honeycombed panels used to reflect light
PERLITE – (1) a sand or volcanic glass, expanded by heat, which holds water and nutrients on its many irregular surfaces (2) mineral soil amendment
PHOSPHOROUS (P) – of, relating to, or containing phosphorus, especially with valence 3 or a valence lower than that of a comparable phosphoric compound
PHOTOPERIOD – the relationship between the length of light and dark in a 24 hour period
PHOTOSYNTHESIS – the process by which plants use light energy to collect carbon dioxide from the atmosphere and convert it to chemical energy in the form of sugar
POLLINATION – the transfer of pollen from a stamen to a pistil. This process is often enhanced by environmental manipulation, plant movement through shaking or vibration or the introduction of bees into the growing area
POLYPLOID – an organism with more than two sets of chromosomes
POTASSIUM (K) – a soft, silver-white, highly or explosively reactive metallic element that occurs in nature only in compounds. It is obtained by electrolysis of its common hydroxide and found in, or converted to, a wide variety of salts used especially in fertilizers and soaps. Atomic number 19; atomic weight 39.098; melting point 63.65°C; boiling point 774°C; specific gravity 0.862; valence 1
PREDATORY INSECT – any variety of insect introduced into a grow area used to combat pests or detrimental infestations
PROPOGATE – (1) Sexual – to produce a seed by breeding different male and female flowers (2) Asexual – to produce a plant by taking cuttings
PRUNING – to cut off or remove dead or living parts or branches of a plant to improve shape or growth
PYRETHRUM – natural insecticide made from the blossoms of various chrysanthemums
- R -
REFLECTOR – the highly reflective, smooth finished hood placed above a lamp to more efficiently direct its light
RESERVOIR (or RES) – any container of a variety of constructions which holds water in reserve for use
REVERSE OSMOSIS (R/O) – water which has had all of its contaminates and salts removed
ROCKWOOL – inert, soil less growing medium consisting of thin strand-like fibres made from rock
- S -
SECONDARY NUTRIENTS – Calcium (Ca) and magnesium (Mg)
SEEDLING – a young plant that is grown from a seed
SHORE FLY – any of numerous minute black flies of the family Ephydridae, living in damp or marshy places
SPIDER MITE – any of various small red mites of the family Tetranychidae that feed on vegetation, causing damage to the leaves
STIMULATOR – any product used to specifically increase one designated area of a plant’s growth cycle
STRESS – the effect a plant faces when it is subjected to a detrimental environment
SYSTEMIC – a term used in reference to a disease within the plant tissue, not initiated from the external cells. This also refers to materials and compounds which are taken up or absorbed by the plant and designed to fight disease
- T -
THRIPS – any of various minute insects of the order Thysanoptera, having usually four narrow wings fringed with hairs, and many of which are major pests of various plants and trees
TRACE ELEMENT – a chemical element required in minute quantities by an organism to maintain proper physical functioning
- U -
UNIFORM GROWTH – ensuring the entirety of the crop receives equal environmental stimulation resulting in equal growth of all plants
- V -
VERMICULITE – mica processed and expanded by heat
- W -
WETTING AGENT – compound that reduces the droplet size and lowers the surface tension of the water, making it wetter
WHITEFLY – any of various small whitish homopterous insects of the family Aleyrodidae, having long wings and a white waxy body, often injurious to plants
WICK – part of a passive hydroponic system using a wick suspended in the nutrient solution; the nutrients pass up the wick and are absorbed by the medium and roots
WORM CASTINGS – the nutrient rich fertilizer created by earthworms
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