Grow terms and definitions (#'s & A - M)

Here’s terms “#” & A through M, that might help the new guys understand what is being said in conversations here. (partial credit goes to “dajosh42069”)

For N-Z click this link:

18/6 - Time normally associated with the vegetative stage of growth i.e. 18 hours of light to 6 of darkness.

12/12 - Timing used to initiate the flowering stage of the plant i.e. 12 hours light to 12 hours darkness.

number/number - The first number refers to the number of hours the lights are ON, and second number refers to the number of hours the lights are OFF.

Abiotic stress - Non-living environmental factors such as frost, drought, excessive heat, etc. that can have harmful effects on plants.

Abscisic Acid - Mediates stress tolerance responses in higher plants, is a key signal compound that regulates stomatal aperture and, in concert with other plant signaling compounds, is implicated in mediating responses to pathogens and wounding.

In seeds, ABA promotes seed development, embryo maturation, synthesis of storage products (proteins and lipids), desiccation tolerance, is involved in maintenance of dormancy (inhibition of germination), and apoptosis. As well, ABA affects plant architecture, including root growth and morphology, and root-to-shoot ratios

Abscission Zone - The zone at the base of the flower (pedicel), fruit (peduncle) or leaf (petioles), at which plant cells fray off, thereby facilitating the easy fall of these plant parts.

Absorption Spectrum - Graph indicating the relative abilities of pigments to absorb various wavelengths of light.

Active Transport - The forceful movement of molecules from one side of the plasma membrane to the other side against a diffusion gradient, by expenditure of energy.

Aeroponics - Is the growing of plants in a container in which the roots are suspended in a nutrient mist rather than in a solution. The most popular container for aeroponics is an enclosed A-frame constructed of styrofoam boards. The plants are placed in holes along the sloped sides of the frame. The nutrient mist is delivered to the roots by a vaporizer or by special attachments available with drip irrigation kits. The mist clings to the roots. Any excess runs down the inside of the frame, is collected at the bottom, and is recycled back
to the nutrient reservoir.

Alternating Leaf - As the plant grows, in the beginning, every leaf (that is not damaged) will have another leaf growing from exactly 180 degrees around the stem. They grow in pairs. When the plants mature, the leaves will grow one at a time. The leaf will pop-out on one side, then, up the stem/branch, another will grow. (I.E. Alternating)

Ammonia - A colorless gas with a characteristic pungent smell. It dissolves in water to give a strongly alkaline solution.

Ampere “AMP” - The unit used to measure the strength of an electric current.

Aquaculture - The rearing of aquatic animals or the cultivation of aquatic plants for food.

Aquaponics - A system of aquaculture in which the waste produced by farmed fish or other aquatic animals supplies nutrients for plants, which in turn purify the water.

Arc - The luminous discharge of electricity between two electrodes in HID lighting.

Arc Discharge - A transfer of electricity across two electrodes (anode and cathode), characterized by high electrode current densities and a low voltage drop at the electrode.

Arc Tube - The enclosure which contains the luminous gases and also houses the arc.

Auto-Flower (Strain) - An Auto-Flowering strain is a strain of cannabis that automatically flowers when it reaches maturity. Meaning you don’t have to Force Flower as you would with other plants (I.E. changing the light cycle to 12/12, thereby causing the plant to flower, anticipating the onset of the fall, and then winter, seasons. Auto flower strains will flower and live out their entire life cycle from sprout to harvest, under 24 hours of constant light, eliminating the need for a timer. Though they WILL still flourish under 18/6, if the grower wants to allow the room to cool.

Auxins - are plant hormones governing many biological processes in higher plants such as cell enlargement and division, differentiation of vascular tissue, apical dominance, root initiation and signaling.

B - (see Boron)

Bag Seed - A seed obtained from a bag of finished cannabis. (Usually the genetic strain of the seed is unknown, which is why we call it a bag seed)

Ballast - An auxiliary piece of equipment designed to start and to properly control the flow of power to gas discharge light sources such as fluorescent and high intensity discharge lamps. In metal halide systems, it is composed of the transformer, capacitor and connecting wiring; sodium systems require an ignitor in addition to the transformer and capacitor.

Base - The end of the lamp that inserts into the lamp socket.

Blood Meal - This organic fertilizer is very high in nitrogen and is very soluble in water (unlike most other dry organic fertilizers). It also contains plant growth regulators. All this together means that its effect is strong and quick, but its power will only last a short while, especially in wet weather. When applying blood meal, take care, as it will easily burn a plant’s leaves.

Boron or “B” - The chemical element of atomic number 5, a nonmetallic solid.

BU - An industry code indicating that the bulb is to be operated only in a base up position.

Bulb - The glass outer envelope component of an HID lamp which protects the arc tube.

Buds - The reason this website exists! -The part of the flowering female plant that contains high concentrations of THC and other psychoactive ingredients.

Bud Leaves - the small leaves that grow in the buds of the plant, usually covered in trichomes when harvested.

Burning Position - The position in which a lamp is designed to be operated.

Ca - (see Calcium)

Calcium or “Ca” - The chemical element of atomic number 20, a soft gray metal.

Calyxes - The sepals of a flower, typically forming a whorl that encloses the petals and forms a protective layer around a flower in bud.

Canopy - The top branches of a plant, usually shading the lower branches, except when branch training methods are used. (See LST, SCROG, and SOG)

Cannabidiol (CBD) - A Cannabinoid in it’s own right and works in conjunction with THC to influence the start and duration of the high. (NOT a byproduct of THC)

Cannabinol (CBN) is a byproduct of THC and is produced via THC degradation from heat/air/light etc., as you describe. It only has a maximum of about 10% THC content and therefore adds little to the ‘high’ over and above making the user feel ‘sleepy’.

(Neither CBD or CBN, are responsible for the ‘stoney’ part of the high nor the ‘psychoactive’ affect the THC has - that is produced solely by THC)

Canoeing - When a plants leaves curl upwards into a V-Shape, usually caused by heat, or malnutrition.

Capacitor - An electronic device that can store electrical charge. The capacitor is one of the main components of an HID lighting ballast. Because they can store a very strong electrical charge, capacitors can be very dangerous to someone who is unaware of this fact and opens a ballast in order to examine or repair it. If one does not know how to safely discharge the stored electricity, one should allow a trained technician to do any ballast repairs.

CFL - Meaning ‘Compact Fluorescent Light’ AKA ‘The Big Curly Bulb’. High Lumen output, small, and power efficient lights. While not the MOST effective, they work very well for their size and power consumption.

CF - “Conductivity Factor”. CF is the same as EC but without the decimal. (0.2 EC = 2 CF),(1.8 EC = 18 CF). Just remove the decimal point from the EC and you have the CF rating.

CFM - Cubic Feet per Minute. This describes the volume of air that is displaced in 1 minute (see ventilation).

Cl - (see Chlorine)

Chemical Nutrients - (see Synthetic Nutrients)

Chloride - A compound of chlorine with another element or group, especially a salt of the anion Cl– or an organic compound with chlorine bonded to an alkyl group.

Chlorine or “Cl” - The chemical element of atomic number 17, a toxic, irritant, pale green gas.

Chlorophyll - The green pigment in leaves. Chlorophyll pigment is produced in the chloroplasts of leaf, stem and flower cells. Chlorophyll pigment dominates all other pigments present including the xanthophylls and carotenes. Chlorophyll captures the sun’s energy which is used to manufacture sugar from carbon dioxide and water. Chlorophylls are constantly being “used up” and thus are continually manufacture by the plant, provided the environmental conditions are appropriate.

Chloroplast - A plastid that contains chlorophyll and in which photosynthesis takes place.

Cloning(s)/Cuttings - Sometimes the easiest (and fastest) way to grow a new plant is not from seed, but asexually from cuttings. Cuttings are taken from roots, stems, or leaves and encouraged to regenerate by providing ideal growing conditions and (oftentimes) applying rooting hormones. Unlike plants started from seed, a plant grown from a cutting will have exactly the same characteristics of the parent plant.

COB - Type of LED lighting. All LED lighting is made up of a light package in one form or other. A COB or ‘chips on board’ light is a type of led package. In COB lighting, single LED chips are placed directly on a circuit board (or substrate) which has thermal properties to disperse heat.

Colas - “The female flowers develop tightly together to form dense clusters (racemes) or buds, cones, or colas”- Mel Frank marijuana Grower’s Guide. Cola’s are the buds you see.

Cold Start Time - The length of time required to bring an HID lamp to 90% light output from a cold condition.

Colour Temerature - see “Kalvin Temperature”

Composting - The process by which organic materials mixed together in specific conditions create a nutrient-rich medium.

Conversion Bulb - A bulb of a certain spectrum type (e.g. sodium) specially designed to operate while used in the fixture/ballast of a different type (e.g. metal halide). The most popular conversion bulbs by far are sodium conversion bulbs, which allow one to have the sodium spectrum while still using a metal halide system.

Copper or “Cu” - a red-brown metal, the chemical element of atomic number 29.

Cu - (see Copper)

Curing - Process of placing the dried harvest in tightly sealed, sterile, jar, which should be stored in a dry, dark, cool place. Then according to preference open the jar for a certain amount of time everyday to release co2 and moisture and this slowly dries the crop, thus improving taste and over all quality.

Cotyledons - small round leaves that are the first to appear on a small seedling, they are not considered true leaves? and often fall off of the plant early in the growth stage.

Decarboxylation -This occurs after buds are harvested and during the curing process. The THC loses a CO2 molecule, which then makes the THC psychoactive. This process is why drying and curing buds after harvest is crucial to the high that the bud produces.

DE “foodgrade” - (see Diatomaceous Earth foodgrade)

Diatomaceous Earth “foodgrade” - a form of sedimentary rock that builds the plankton in oceans and ponds. It is being formed from fossilized remains that are known as diatoms. Diatomaceous earth has been found in studies to kill insects by removing a portion of the razor-thin, waxy outer coating that helps an insect conserve moisture, which allows them to work better than other products that relay on abrasion or poisoning.

Discharge Lamp - A lamp that produces light by discharging an electric arc through a mixture of gases and gaseous metals.

Dome - The portion of an HID outer bulb located opposite base (the neck and threads).

Dome Support - The spring-like brackets which mount the arc tube within the outer envelope (bulb).

DWC - Means ‘Deep Water Culture’. In its most basic form its a plastic bin full of hydro solution to a certain level on net pots suspended by way of holes in the containers lid and the plants roots are basically fed buy an air pump bubbling the solution. However, this is a very basic description of the practice.

Electrodes - Filaments located at either end of a discharge lamp that maintain an electrical arc between them.

Fe - (see Iron)

Feminized Seeds - Seeds which have a higher likelihood of sprouting female.

FFOF - Means ‘Fox Farm Ocean Forest’, It’s a soil commonly used by growers for it’s properties and ability to grow.

Fish emulsion – This is a liquid organic fertilizer with a NPK ratio of about 4-1-1 to 7-2-2. It is water soluble and thus immediately available to plants. It is valued for its high nitrogen content.

FIM - An acronym for “F*ck I Missed!” A variant of the topping technique, here only a portion of the growth tip is removed, causing an increase in resulting cola sites. (See topping).

Fixture - The electrical fitting used to contain the electric components of a lighting system.

Flr, Flouro, Floro’s - Fluorescents come in a wide variety of shapes and sizes. There are compacts, twist bulbs and circle bulbs. They all work the same way. They have a starter and ballast which help provide a steady and regulated amount of electricity to the light.

FLIR - Means ‘Forward-Looking Infrared’, It is a thermal imaging process whereby differences in heat emission are measured and reflected on a videotape. Heat concentration is indicated on a videotape on a spectrum of light to dark, with bright white showing intense heat. Increasingly, law enforcement personnel are using FLIR thermal imaging to detect indoor marijuana growing operations. However, the Supreme Court in the U.S. has recently banned the use of FLIR to find these operations.

Fluorescent Lamp - A discharge lamp in which a phosphor coating transforms ultraviolet energy into visible light. Fluorescent lamps are good for starting seedlings and rooting cuttings, but do not have enough intensity to sustain aggressive growth in plants in the later stages of life, and are not efficient enough in their conversion of electrical power to light output.

Flush - the act of cleansing a plants roots of nutrients and contaminants by giving the plant large amounts of water (usually equal to 3 times the volume of soil the plant is in).

Foliar Feeding - The act of giving water and/or nutrients to the plant through the leaves instead of through the roots.

Force Flowering - Giving a female plant a photoperiod of 12/12 to force the plant into producing buds. Doing this mimics the natural light cycle of the sun and the Fall season, and then the winter season, approaches.

Frequency - The number of waves or cycles of electromagnetic radiation per second, usually measured in Hertz (Hz).

Garlic - When planted in the same pot/area as your plants, will act as a natural systemic insecticide to both Green flies and Black flies. The plants absorb it from the growing garlic. It DOES NOT affect the plants scent or taste, can also be used for the same purpose in other plants.

Genotype - Is the plants characteristics as received from its parents genetic traits.

Germinate - To open a seed and allow growth by planting it, or using various methods to allow the seed to open and the first root to come out before planting it. Allowing the seed a better chance of breaching the surface.

GH - Means ‘General Hydroponics’

GA - Means ‘Gibberellic Acid’ - A hormone used to promote plant growth, especially that of seedlings, and obtained from the fungus Gibberella fujikuroi (GA) is used to reduce flowering and fruiting which maximizes growth and minimizes pollen transmitted. GA is also used in mature plants to increase the fruiting capacity by stimulating the development of lateral shoots and spurs.

Halogen Lamp - A short name for the tungsten-halogen lamp. Halogen lamps are high pressure incandescent lamps containing halogen gases such as iodine or bromine which allow the filaments to be operated at higher temperatures and higher efficacies. While excellent for home lighting and similar applications, halogen lamps are not effective or efficient as grow lights due to their very poor spectrum (extreme far red) and high operating temperatures.

Harvesting - The act or process of gathering a crop. By trimming the buds off, or branches that hold them, and using one of the many methods of drying. Once dried, the option is then available to cure. (See Curing)

Herbs - Aromatic plants used for seasoning, medicinal purposes, or garnishes. Aromatic herbs are the ones that have fragrant or smelly leaves or flowers. Cannabis leaves are sometimes used as a Herb.

Hermie / Hermaphrodite - A plant that changes sex midway through it’s life cycle, to have both FEMALE and MALE characteristics. Due in part to many factors, but primarily due to stress (I.E. light stress, heat stress, nute stress) or improper dark cycle. (I.E. not sealing off the grow area properly and not letting the plant get 100% COMPLETE darkness)

HID - see “High Intensity Discharge Lamp”

High Intensity Discharge Lamp - A general term for mercury, metal halide and high-pressure sodium lamps. HID lamps contain compact arc tubes which enclose various gases and metal salts operating at relatively high pressures and temperatures.

High Pressure Sodium Lamp - High-pressure sodium lamps operate by igniting sodium, mercury and xenon gases within a sealed ceramic arc tube. Sodium lamps emit light energy in the yellow/red/orange regions of the spectrum; the red spectrum stimulates flowering and fruit production. Many indoor gardeners switch to sodium lamps when it is time to induce flowering or fruiting of their plants. Probably the best light available for growing marijuana indoors. High Pressure Sodium lights are very bright and very efficient. This light has a red/orange spectrum that is ideal for the flowering phase. With enough of these kind of lights you too can grow those centerfold buds. HPS comes in a wide variety of wattages from 70 watts up to 1000 watts.

HPS - see “High Pressure Sodium Lamp”

Hood - The reflective cover used in conjunction with an HID lamp. The more reflectivity a hood can provide, the more effective it is.

HOR - An industry code indicating that the bulb is to be operated in a horizontal position.

Hormone - A biochemical product of a specific cell or tissue that causes a change or activity in a cell or tissue located elsewhere in an organism.

Hot Spot - The area immediately under an HID lamp where the light intensity is strongest, hot spots cause uneven growth, but can be remedied by using light movers or air-cooling the encased hood.

Hot Start Time - The length of time required to bring an HID lamp to 90% light output after a short power interruption.

Hydroponics - The growing of plants without soil, instead using a medium like clay pebbles, rockwool-floc or perlite and vermiculite mixture. And giving the plant all the nutrients through the water the roots are in.

Humus - A complicated material formed during the breakdown of organic matter. One of its components, humic acid, provides many binding sites for plant nutrients, such as calcium, iron, potassium, sulfur and phosphorus. These nutrients are stored in the humic acid molecule in a form readily available to plants, and are released when the plants require them.

Hybrid - Often refers to a plant or variety that has been developed by interbreeding two or more varieties, species, or genera

IBL - Inbred line, a homogeneous strain that shows uniform growth characteristics from seed

Ignitor - A component of the ballast necessary for the starting of the bulb in sodium systems.

Incandescent Lamp - A light source which generates light utilizing a thin filament wire (usually of tungsten) heated to white heat by an electric current passing through it. Incandescent lamps are the most familiar type of light source, with countless application in homes, stores and other commercial settings. Light is produced by passing electric current through a thin wire filament, usually a tungsten. Incandescent lamps are totally ineffective as grow lights; they have very limited spectrum, are very inefficient in their conversion of electrical power to light output they also put off far too much heat per watt to use in horticulture, even if the above-mentioned problems did not exist.

Indica - Indica is a great plant to grow indoors as well as outdoors due to its low lighting requirements and tight internode spacing, also offering resistance to fungus and pests, early maturation tendencies, and dense flower production. Indica’s come from colder climates exhibiting the traits described above by acclimating to the environment from whence they came. Their stout stature and extremely wide leaflets make them easy to identify. An Indica generally produces a hard hitting, tiresome, sedative stone, and will take around 45 to 60 days to finish flowering.

Intensity - A term referring to the magnitude of light energy per unit; light intensity diminishes evenly as you get further from the source.

Iron or “Fe” - a strong, hard magnetic silvery-gray metal, the chemical element of atomic number 26, much used as a material for construction and manufacturing, especially in the form of steel. In nutrients, it’s often in chelated form as FeEDTA, FeDPTA, FeEDDHA.

K - (see Potassium)

Kalvin Temperature - The unit of measurement to express the colour (spectrum) of light emitted by a lamp; the absolute temperature of a blackbody radiator having a chromaticity equal to that of the light source. A standard clear metal halide HID lamp has an average Kelvin temperature rating of 4,000K.

Kilowatt (kW) - A unit of electric power usage equal to 1,000 watts.

Kilowatt Hour (kWh) - A measurement of electric energy. A kilowatt hour is equal to 1,000 watts of power used over a period of one hour.

Leggy - If seedlings and plants do not get enough sunlight, they grow tall and thin stalks as they seek sunlight. These “leggy” plants have a difficult time supporting the weight of the plant and is easily damaged. (See Stretching)

Light burn - When the heat from a light burns the plant.

Lollipopping - Refers to cutting the bottom branches off of a plant to allow the top portion to bud more vigorously. Term refers to the ‘lollipop’ shape of the stalk and bud.
( )
( ) <—bud
( )
l<-----stalk (trimmed of side branches)

Lumens - One lumen is equal to the amount of light emitted by one candle that falls on one square foot of surface one foot away.

LST - “Low-Stress Training” The technique of manipulating the branches in order to reduce plant height, expose certain branches to light, and/or distribute hormones to lower branches of the plant to encourage larger buds.

M² - Meters Squared.

Macronutrients - For a plant, there are nine major elements essential for healthy growth; these are called macronutrients. They are: carbon, hydrogen, and oxygen (which are all three derived from air and water); and nitrogen, phosphorus, potassium, calcium, sulfur, and magnesium (from the soil).

Magnesium or “Mg” - The chemical element of atomic number 12, a silver-white metal of the alkaline earth series. It is used to make strong lightweight alloys, especially for the aerospace industry, and is also used in flashbulbs and pyrotechnics because it burns with a brilliant white flame.

Manganese or “Mn” - The chemical element of atomic number 25, a hard gray metal of the transition series. Manganese is an important component of special steels and magnetic alloys.

Mb - (see Molybdenum)

Mg - (see Magnesium)

Mn - (see Manganese)

Micronutrients - There are about eight nutrients essential to plant growth and health that are only present in very small quantities. These are manganese, boron, copper, iron, chlorine, cobalt, molybdenum, and zinc.

Medium - A soil or soil-less mix used to start or re-plant houseplants, flowers, vegetables, and other plants

Mids - Medium grade cannabis. (See Shwag)

Molybdenum or “Mb” - The chemical element of atomic number 42, a brittle silver-gray metal of the transition series, used in some alloy steels.

Mottling of Leaves - Discoloration or spotting of leaves.

MV - Means ‘Mercury Vapor’ And is the type of lights that were used for streetlights many years ago. Not very good for growing because it doesn’t provide enough of the right kind of light spectrum. While they do provide a little of the blue spectrum, MV also produces too much heat to get very close to a plant, and are very inefficient to operate.

MH - “Metal Halide” A very good source of the white/blue spectrum of light that is ideal for vegetative growth. Many growers use MH during the vegetative phase. MH is bright and cost efficient to operate, but not as efficient as HPS lights. Most commonly used sizes are 400 watt and 1000 watt. Works best when used in combination with HPS lights.


Thanks for posting. Just this A.M. I noticed a new grower mentioning his lack of knowledge in these terms. :slight_smile:

Moved to GrowFAQs