Ever wonder what all the “growing terms” mean? Here is a complied list of definitions to every word, expression, and phrase relating to cannabis use and growth.
A-lamp: n. Standard incandescent lamp.
Absorption: n. The process by which plants take up water through their roots.
AC/H (Air Changes per Hour or Air Change Rate): Measure of the air volume added to or removed from a space divided by the volume of the space. If the air in the space is either uniform or perfectly mixed, air changes per hour is a measure of how many times the air within a defined space is replaced. 20 AC/H is considered optimal for cannabis cultivation, cooling load notwithstanding.
- N = number of air changes per hour
- Q = Volumetric flow rate of air in cubic feet per minute (cfm)
- Vol = Space volume L × W × H, in cubic feet
acid: (an acidic solution) A solution with a pH of 0-7.0.
acidify: v. To lower the soil’s pH to meet the characteristics of acid soil.
activated carbon: n. Ionized carbon granules, typically the main component in filters, effective in removing impurities from air and water. Activated carbon filters are effective in odors from air.
activator: n. Any of various substances such as microorganisms and nutrients, which, when added to a compost pile, speed the breakdown of organic matter. Also called compost activator and compost inoculant.
active air intake: n. Means of ventilating enclosed spaces with the use of mechanical fans or pumps. (ant. passive air intake).
adsorption: n. Condensation on the soil’s surface. The adhesion of molecules of gas, liquid, or dissolved solids to a surface.
aerate: v. 1. To expose to the air. 2. To charge with air. Hydroponics operations often aerate nutrient solutions to reduce algae and bacterial growth and increase oxygenation.
aeration: n. An exchange of air in the soil with air from the atmosphere.
aeroponic: n. Variant of hydroponic cultivation in which liquid nutrient chemicals are aerosolized and sprayed on plant roots to increase oxygenation and nutrient solubility. Aeroponics is considered an advanced form of hydroponics and can help achieve slightly greater yields and faster growth when properly tended.
algae: n. Simple organisms of the plant kingdom, lacking roots, stems, leaves, and flowers. Most grow in water, such as seaweeds or pondweeds. Seaweeds are valuable as fertilizers.
alternate: adj. 1. Placed at uneven sequences upon the stem, as alternate leaves, which are solitary at the junction with the stem, in distinction from opposite or whorled. 2. Opposite to the intervals between organs, as petals that are alternate with sepals, or stamens with petals. Cannabis plants are often transferred from vegetative growth to flowering when upper leaf stems begin to alternate.
aluminum sulfate: n. A colorless salt used as a soil amendment to increase soil acidity.
amendment: n. A term for any conditioner or material (like lime, gypsum, etc.) that is added or worked into the soil to make it more productive. Soil amendment is often required for successful outdoor growing.
ammonium nitrate: n. 1. An inorganic fertilizer used to add nitrogen to the soil. 2. The form that nitrogen takes in numerous commerical fertilizers.
ammonium sulfate: n. An inorganic fertilizer applied to soil (20.6% N)
ampere: (AMP) n. A unit of measure of the rate of electron flow or current in an electrical conductor. One ampere of current represents one coulomb of electrical charge (6.24 x 1018 charge carriers) moving past a specific point in one second.
annual: n. Plant that lives one season or up to one year. Annuals can be carried over into a successive seasons by preventing them from setting seed. Cannabis is an annual plant.
anther: n. The part of a stamen that contains the pollen, usually located at the end of a slender stalk often in the center of a blossom.
apatite: n. 1. Chief mineral found in phosphate rock. 2. An inorganic compound found in bones; a component of bone meal.
aphid: n. Any of several kinds of small, colored insects, usually congregate on new growth (which often becomes distorted) of a great variety of plants, including ornamentals, like roses, and vegetables, like cabbage and broccoli. Easily controlled by insect predators, insecticidal soap, botanical insecticides, or traditional pesticides.
aphid trap: n. A pheromone-baited (scent-baited) device to lure and capture aphids.
Aphytis wasp: n. (see scale parasite.)
apophyllous: adj. In botany, having distinct leaves, applied to a whorled flower with distinct sepals and petals
arc: (in a lamp) n. Luminous discharge of electricity between two electrodes in HID lighting.
arc discharge: n. Transfer of electricity across two electrodes (anode and cathode), characterized by high electrode current densities and a low voltage drop at the electrode. (see high intensity discharge).
arc tube: n. Enclosure which contains the luminous gases and also houses the arc.
attenuate: adj. Tapering gradually to a narrow point. Most cannabis strains are known for their natural attenuate phenotype, similar to a “pine tree.” Training, pruning, and other methods are used to alter the shape to avoid detection, as well as enhance branching.
asexual propagation: v. (see clone)
auxin: n. 1. Naturally occurring plant hormone which promotes branching and root growth 2. Organic substance characterized by its ability to promote growth, particularly of roots. It is an active ingredient in rooting compounds.
axis: n. The stem; the central part or upright support of a plant to which organs or parts are attached.
bactericide: n. Agent that kills bacteria; specifically, that which kills bacterial plant diseases.
baking soda: n. Sodium or potassium bicarbonate. Sometimes mixed with horticultural oils and applied to plants to prevent fungal diseases, such as black spot and powdery mildew.
bagseed: n. Slang for seeds present in dried marijuana acquired primarily for smoking. Bagseed can be successfully propagated but with sometimes unreliable or undesirable results.
ballast: n. Electrical device consisting of a transformer, a capacitor, and in some cases, and ignitor, and used most commonly with commercial fluorescent light fixtures and also found in high intensity discharge fixtures. The ballast provides a constant, regulated flow of electricity which reduces fluctuation in lumen output and protects the lamp from power surges and current falloff.
base: n. 1. An alkaline solution. 2. A solution with a pH of 7.1 or higher.
bast: n. 1. Woody fiber obtained from the phloem, or inner bark, used to make cords such as hemp, jute, ramie, etc.
beans: n. pl. Slang term for cannabis seeds.
bendiocarb: n. Synthetic insecticide used to control a variety of house and garden pests.
benomyl: n. Systemic fungicide used to control a variety of diseases of ornamentals, usually foliar. It is absorbed into the system of the plant to fight off infection. Common trade name: Benlate.
binomial :adj. 1. Using or having two names.
biodynamic: adj. Of, or concerned with, the dynamic relation between organisms and their environment.
black spot: n. Fungal disease causing black spotting on foliage and stems. Most common in areas with summer rain and/or high humidity. Good winter cleanup (destroying infected leaves and prunings) and spring fungicide sprays are effective controls.
blister beetle: n. Voracious feeding, swarming insect that devours many garden vegetables and ornamentals. When crushed, irritants exuding from the beetle can cause blisters on the skin, hence the name. Wear gloves when handling. Pyrethrum-rotenone combinations, parasitic nematodes, and traditional insecticides are effective controls.
blood meal: n. Soluble fertilizer high in nitrogen and derived from dried livestock blood. Used primarily in organic gardening.
blower: n. Air handling device for moving air in a distribution system.
bone meal: n. Ground bone, raw or steamed, that is used as a fertilizer to add phosphoric acid to the soil in organic gardening.
botanical insecticide: n. Any of various natural insecticides derived from plants. They include pyrethrum, neem, rotenone, rynia, sabadilla, and nicotine sulfate. They break down quickly when exposed to sun and must be applied frequently. They usually are nontoxic but not always (see nicotine sulfate).
bract: n. Leaf in a flower cluster or a leaf base of a flower, usually differing somewhat from an ordinary leaf in size, form, or texture; often much reduced but occasionally large and showy. Sometimes petallike, highly colored, and very conspicuous.
bracteate: adj. Having bracts.
breeding: v. Propagation of selected plants to develop distinctive qualities, such as yield, size, and disease resistance.
BU: n. Industry code indicating that a lamp is to be operated only in a base up position.
bubble hash: n. Highly purified form of smokable hash, consisting of refined, pressed cannabis resins that “bubble” when smoked.
bud: n. Smokable flowers of a cannabis plant. Used interchangeably as both the entire cola and the individual flowers that are cleaned from the stem and smoked.
buffer: n. Substance in the soil that will chemically act to resist changes in the soil’s reaction or pH, usually clay or fine organic matter.
bulb: n. Glass outer envelope component of a lamp which protects the arc tube or filament.
bulb wall temperature: n. Temperature at the bulb wall of a lamp, which effects lumen output and input wattage and which is important in lighting calculations.
burnt lime: (CaO) n. Caustic solid used to neutralize acid soil or to raise the pH of soil.
bushy: adj. Short, full growth with multiple branching and numerous leaves, attributed to abundant light.
calyx: n. The flower of the cannabis plant, consisting of two long white or colored hair-like pistils surrounded by a stipule of bracts (reduced leaves) and covered with resin exuding glandular trichomes.
candela: n. Unit of luminous intensity in a given direction, equal to one lumen per steradian. Historically equal to one candle of spermaceti (whale fat) so constructed to burn at the rate of 120 grains, or 7.8 grams, per hour, over one square foot of surface area, at a distance of one foot. In the metric system, a candela is equal to 1/60 of the luminous intensity per square centimeter of a blackbody radiating at 2046 degrees Kelvin.
candlepower: (CP) n. Luminous intensity of a light source, as expressed in candelas.
candlepower distribution curve: n. Graph that represents the varying distribution of luminous intensity of a lamp or luminaire.
Cannabaceae: n. Family of 2 genera and 3 species; the hemp family. The 2 genera are Cannabis, true hemp, or marijuana, and Humulus, commonly known as hops. It is illegal to grow Cannabis sativa in the United States without a government permit. Humulus lupulus is grown as a summer vine and is an important ingredient in beer.
Cannabis: n. 1. Genus of a single species, C. sativa, with long, toothed leaves and spikes or clusters of flowers. (See hemp.) 2. Generic reference to any of several strains of annual dioecious plants, native to central Asia, and having alternate, palmately divided leaves and tough bast fibers which produce a mildly euphoric, intoxicating and/or hallucinogenic effect when smoked or eaten.
cannabutter: n. Cooking paste created from resins extracted from discarded cannabis leaves and stems in boiling water and butter. Water is boiled off or evaporated and remaining butter is hardened and used in foods prepared to give a psychoactive response, such as brownies, cookies, and other baked goods.
capacitor: n. Electronic device that can store electrical charge. The capacitor is one of the main components of an HID lighting ballast.
carbon scrubber: n. (see activated carbon).
CFM: (Cubic Feet per Minute) Unit of air flow used to rate fan output, equal to the movement of one cubic foot of air every minute.
chitin: n. Natural pesticide made from ground-up crustacean shells and added to soil to increase the feeding of soil organisms on nematode eggs.
chlorophyll: n. Green pigment found in plant chloroplasts (glands) through which assimilation of plant food takes place. The curing process helps eliminate chlorophyll which aids in reducing harshness of smoke.
clone: n. New plant propagated from a mother with desirable genetics by cutting and inducing roots, either by natural hydration of by use of chemical hormones. v. To propagate a new plant with desirable genetics by same means.
CO2 enrichment: v. Technique of adding carbon dioxide to the growth environment to enhance photosynthesis and chlorophyll production and thus biomass. Methods of enrichment include using bottled gas with regulators and timers, yeast cultures, and vinegar and baking soda.
cola: n. Portion(s) of the cannabis plant consisting of a dense cluster of stigmas, pistils, sepals, fan leaves, and (if pollinated) seeds. Syn. bud.
cold start time: n. Length of time required to bring an HID lamp to 90% light output from a cold condition.
color temperature: n. Unit of measure to express the color (spectrum) of light emitted by a lamp; the absolute temperature of a blackbody radiator having a chromaticity equal to that of the light source (see correlated color temperature).
Lamps rated at 6500 degrees K radiate primarily in the blue/green portion of the color spectrum, which mimics the spring and early summer sun and is most commonly used for vegetative growth; those rated at 2500 K radiate primarily in the red/orange portion of the spectrum, which mimics the late summer and early fall sun and is commonly used to induce flowering.
correlated color temperature: (CCT) n. Specification of the color appearance of a light source, relating its color to that of a blackbody radiator, as measured in kelvins (K). CCT is a general measure of a lamp’s “coolness” or “warmness.”
compost tea: n. (see worm tea).
continuous grow: n. Simultaneous cultivation of several cannabis plants at many stages of development to produce a regular yield at short intervals.
conversion bulb: n. Lamp of a certain spectrum type specially designed to operate while used in the fixture/ballast of a different type. The most common conversion bulbs create sodium spectrum using a metal halide system.
cool tube: n. Glass sleeve installed around a lamp and connected to a ventilation source to actively discharge heat.
copper: n. Element used in various forms, including copper sulfate and Bordeaux mixture, to control fungal and bacterial diseases of plants. Also used in strips around shrub stalks and tree trunks to act as a barrier to snails.
cull: v. To remove rejected members of a group, specifically something of inferior quality. In cannabis cultivation, male plants are culled from the growing room to prevent pollination and to focus resources on female plants.
curing: v. Process of aging harvested cannabis plants to increase quality. Curing decreases chlorophyll content to decrease harshness and allows decarboxylation to occur, increasing psychoactive properties. Dried buds are typically cured in sealed glass or plastic containers for up to 2 weeks.
daylight lamp n. lamp with altered color characteristics to mimic key portions of sun spectrum, usually blue/green (6000-7500 degrees K). Daylight corrected lamps are frequently used in growing because of their greater concentration of light in wavelengths beneficial to plants.
decarboxylation: n. Removal of a carboxyl group from a chemical compound. Decarboxylation of THC occurs naturally while curing, increasing its psychoactive effect.
dendroid: adj. Treelike; dendriform; arborescent; branching like a tree. Cannabis plants have dendroid characteristics.
denitrification: n. Process by which bacterial action reduces nitrates in the soil to ammonia or free nitrogen that can escape into the air.
denticulate: adj. Finely dentate; edged with minute toothlike projections: such as, a denticulate leaf, calyx, etc.
dioecious: adj. Having male and female reproductive organs borne on separate individuals of the same species. Only female cannabis plants that are prized for their sexual organs, or buds. Syn. sex.
direct seeding: v. Sowing seeds directly into the soil.
ditchweed: n. Slang for low potency cannabis plants growing wild and unattended.
dome: n. Portion of an HID outer bulb located opposite base (the neck and threads).
dome support: n. Spring-like brackets which mount the arc tube within the outer envelope (bulb).
drip irrigation: n. 1. System of watering by which moisture running through a porous hose is slowly released through tiny holes, or emitters, to the root zone of plants. 2. Simple hydroponic system in which water and nutrient solution is delivered to the roots by same means.
drying: adv. Water content reduction in plants, by either natural or artificial means. Ideally, plants are dried without additional heat, which can affect chemical properties. Harvested cannabis plants should have stiff but slightly pliable stems prior to curing. Cured buds should be further dried prior to long term storage to eliminate risk of mold and enhance combustibility.
Dursban: n. Common synthetic insecticide (chemical name: chlorpyrifos) used to control a variety of pests. Effective against ants and many soil- dwelling insects.
early sexing: v. Technique of determining sex of cannabis plant by introducing a photoperiod on one branch prior to inducing flowering on the entire plant. Techniques include covering the branch with light blocking bags/tarps or threading branches through light blocking partitions into a separate flowering chamber.
efflorescence: n. Time or state of flowering; anthesis.
enantioblastic: adj. Pertaining to a plant embryo, originating at the end directly opposite the hilum (seed scar).
episperm: n. Hard external covering of a seed
epithet: n. Part of the scientific Latin name of a plant which follows the name of the genus and identifies the species, variety, or other sub-unit. In the name of the moss rose Rosa centifolia muscosa, centifolia is the specific epithet, and muscosa is the varietal epithet.
electrode: n. Filament located at either end of a HID lamp that maintains an electrical arc, usually in a gaseous or near vacuum environment to produce light. (see high intensity discharge.
evapotranspiration: n. 1. The loss of water from the soil by evaporation and plant transpiration. 2. Water on the surface taken away by water, wind, air, and elements.
extrafloral: adj. Of a plant part that does not form part of a flower.
fan: n. (see blower).
female: n. In botany, a plant that produces fruit; that plant that bears the pistil and receives the pollen or fertilizing element of the male plant, or the analagous organ in cryptogams.
feminized: adj. Description of seeds that have been bred for higher incidence of female plants.
ferric iron: n. Oxidized or high-volence form of iron.
ferrous iron: n. Reduced or low-volence form of iron.
fert: (see fertilizer.)
fertigation: v. Combined automation of irrigation and fertilization with nutrient supplements into one process.
fertilizer: n. Combination of minerals and chemicals added to soil to enhance plant growth and characteristics. Fertilizers generally consist of varying mixtures of Nitrogen, Phosporus, and Potassium as well as other trace elements and minerals essential to sustain plant growth. (see N-P-K.)
FIM : Colorful euphemism for technique requiring removal of 90% of growth tips to induce branching and increase number of colas. FIM is attributed to the phrase “F uck, I Missed!”
fimble: n. Male hemp plant or the fiber made from it. Also called fimble hemp.
fish emulsion: n. Nitrogen-rich organic nutrient solution prepared from herring, sardine, and anchovy fish oil extracts, used primarily in foliar feeding.
flaccid: adj. Limp, lacking strength; weak.
flea beetle: n. Tiny, hopping insect that attacks a variety of plants. They usually start by eating small holes in leaves; the plants then wither or look scalded. They are very destructive and harmful viruses to plants. Control with sanitation, rotenone or pyrethrin sprays on vegetables, or traditional insecticides.
flex duct: n. Round metal or plastic ducts that can be bent around obstacles or repositioned used in HVAC systems. (slang: flex)
flowering: v. Cycle when plant energy is focused primarily on reproduction through blooming, sexual propagation, and seed creation.
fluoro: (see fluorescent.)
fluorescent: n. Type of lamp consisting of unpressurized inert gasses excited by electrical current to create ultraviolet light, which reacts with phosphor coatings inside a glass tube to create fluorescence. Fluorescent lamps emit more lumens per watt and less heat than incandescent lamps. Alteration of gas mixture and coatings on fluorescent tubes yields various color temperatures. Many fluorescents require ballasts to regulate electrical flow to maintain a constant output. Low wattage fluorescent lamps are generally inexpensive, widely available and inexpensive to operate, thus they are commonly used by small grow operations for limited numbers of plants. Light from fluorescent lamps quickly diminishes in intensity moving away from the bulb surface, requiring training of plants and frequent movement of lights to accommodate plant growth.
footcandle: n. Standard measurement of light intensity, representing the amount of illuminance on a surface one foot square on which there is a uniformly distributed flux of one lumen. More simply, one footcandle of illuminance is equal to the light emitted by one candle at a distance of one foot.
foliar: adj. Consisting of or pertaining to leaves.
foliar feeding: v. Fertilization by spraying diluted nutrient solution directly onto leaves.
frequency: n. Number of waves or cycles of electromagnetic radiation per second, usually measured in hertz (Hz).
ganja: n. Term for cannabis used in India.
genetics: n. Slang term for genetic characteristics among various strains of cannabis plants. Also slang term for high quality seeds of strains with known characteristics and most often acquired from seed banks.
geotropism: n. 1. Tropism in which gravity is the orienting factor, up or down. 2. In botany, tropism in which growth is toward the earth.
germination: n. Initial activation of a seed caused by the softening of the seed casing by water and indicated by a single root, called a tap root, forced through the casing and drawn down into soil by gravity.
genotype: n. Genetic makeup, as distinguished from the physical appearance, of an organism or a group of organisms.
guano: n. Strong organic fertilizer composed of droppings, primarily or birds or bats.
guerilla cultivation: v. Tactic of outdoor cultivation on property away from the cultivators base of operation to reduce risk of identification.
halogen: n. Type of incandescent which emits light in the red/orange (2500 degrees K color temp). Halogen lamps produce more heat per watt than other lamps of equal wattage and color temperature and thus are not often used for growing.
hardening off: v. Process of gradually acclimatizing greenhouse- or hotbed-grown plants to outdoor growing conditions.
hash: n. Generic term for low potency cannabis plants cultivated primarily for their trichomes, or crystallized THC, present on leaves. Also refers to the smokable/digestible product extracted from cannabis plants, purified by various means, and pressed into small wafers, and smoked or eaten. (also see Shake, Bubble Hash)
hashish: n. Common name for the tops and tender parts of Cannabis sativa, a tall plant with long, toothed, hand-shaped leaves and spikes or panicles of flowers. Commonly known as pot, marijuana, ganjah, bhang, or Indian hemp. Also spelled hasheesh.
heavy soil: n. Term to indicate a clayish fine-textured soil.
heliophilous: adj. Fond of the sun; attracted by or becoming most active in sunlight. Cannabis is considered a heliophilous plant.
hemp: n. 1. Common name for the genus Cannabis, an annual herbaceous plant cultivated primarily for its tough, versatile, high quality fibers and viscous oil and used in a variety of industrial applications such as textiles, paper-making, rope and twine, and machinery lubrication.
herbaceous: adj. 1. Not woody, pertaining to a plant or stem: dying to the ground each year, usually in winter. 2. Leaflike in color texture.
hermaphrodite: n. Plant which exhibits some qualities of both male and female plant yet does not fully develop male stamens and anthers or female calyxes and pistils. Stress, disease, inadequate light, and poor genetics are understood to be causes of hermaphrodism in plants.
HID: abbr. (see high intensity discharge)
high intensity discharge: n. Specialized lamp consisting of a pressurized mix of gasses excited by an electrical arc and designed for high lumen output within a specific color temperature. Types of high intensity discharge lamps include metal halide, high pressure sodium, and mercury vapor.
high pressure sodium: n. HID lamp containing sodium, mercury and xenon gases within a sealed ceramic arc tube and emiting light in the red/orange wavelength (2500 degrees K color temp). HPS lamps are commonly used in flowering stage, although color corrected or daylight HPS lamps are sometimes used all cultivation stages.
hood: n. (see reflector)
hor:. abbr. industry code indicating that the bulb is to be operated in a horizontal position.
hot spot: n. 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.
hot start time: n. Length of time required to bring an HID lamp to 90% light output after a short power interruption.
HPS: abbr. (see high pressure sodium)
humate: n. Salt of humic acid. In cultivation, humate is used as a generic term for any number of highly compressed organic solids and is collected and sold as an admixture in organic gardening and nutrient for hydroponics.
hummus: n. General term for soil containing rich organic compounds, beneficial bacteria, and low in mineral content. Hummus has a tendency to drain poorly, and is used as a base for soil preparation along with peat, sand, clay, and artificial admixtures such as perlite.
HVAC: abbr. 1. Heating, Ventilation, Air Conditioning. Industry term for any mechanical means of regulating temperature and supplying ventilation to enclosed spaces. 2. High Volume Air Conditioning. Subspecialty involving the cooling of large spaces, typically in industrial settings.
hydrogen peroxide: n. H202. clear liquid, reactive solution which decomposes quickly into water and one free oxygen atom. Used as an anti-fungal agent in soil and hydroponics operations at 3% solution. Has been attributed to enhanced oxygen concentration at plant roots when free oxygen atoms combine with one another to form O2, although the effect of free radicals in plant soil is not well understood.
hydroponic: n. Technique of horticulture relying on chemical nutrient solution fed directly to plant roots suspended in a sterile, non-organic medium. Hydroponic systems, when properly tended, are attributed to faster growth, healthier plants, and higher yields than traditional growing methods.
icterus: n. In botany, jaundice.
ignitor: n. Component of the ballast necessary for the starting of the bulb in HID systems.
illuminance: n. Density of incident luminous flux on a surface; illuminance is the standard metric for lighting levels, and is measured in lux (lx) or footcandles (fc).
inbreed: v. To subject to inbreeding; to breed from individuals of the same parentage or otherwise closely related.
incandescent: n. Type of lamp consisting of an electrified filament suspended in a near-vacuum environment. Incandescents are not commonly used in horticulture because of their low color temperature and high inefficiency.
indica: n. Family of cannabis strains known for robustness and tall growth. Often hybridized with sativa strains to create a mixture of desirable characteristics.
infiltration rate: n. Rate of water entering the soil that is controlled by surface conditions.
inorganic: adj. 1. Not natural; not organic; artificial. 2. Composed of other than animal or plant matter; mineral.
insecticidal soap: n. A low-toxicity pesticide made from the salts of fatty acids. It kills soft-bodied insects, like aphids, spider mites, thrips, and whiteflies, by disrupting cell membranes. (Make your own by mixing 2 tablespoons dishwashing detergent in 1 gallon of water.) It may burn foliage in hot weather. It is sometimes combined with other materials, such as citrus oil or sulfur, to increase efficiency. Complete coverage of the plant is essential to control.
internode: n. Part or space between 2 nodes.
internode spacing: n. Refers to length of stem between nodes. Generally, short internode length indicates optimal light intensity and color temperature for vegetative growth. Longer internode spacing indicates a phototropic response in the plant to stretch towards a low intensity light source.
involute: adj. Rolled inward, as the margin of a leaf.
iron: n. Soil nutrient required by plants to manufacture chlorophyll. In dry, alkaline soils, plants may not be able to absorb iron from the soil, which causes the leaves to turn yellow with green veins. Products containing iron chelates may be added to the soil or sprayed on foliage to make iron available to the roots and leaves.
Japanese beetle: n. Very destructive pest introduced from Japan. The adult beetles feed voraciously on the foliage of many plants, especially deciduous trees. The grubs feed on plant roots. The beetles can be controlled somewhat with pheromone traps; the grubs can be effectively killed using Bacillus popillea or parasitic nematodes. Traditional pesticides are also effective.
Japanese beetle trap: n. A container baited with floral and/or sex scents to capture the voracious, garden-consuming Japanese beetle.
jointed: adj. Having nodes.
K+: abbr. slang for “good karma” on internet forums. Indication of general support of or agreement with a post or thread.
K-: abbr. slang for “bad karma”. Indication of disagreement with a post or thread.
kainite: n. Natural salt contained in a fertilzer that is used as a source of potash (14% k).
kelp: n. Any of various brown, often very large seaweeds with leathery fronds of the order Laminariales. Dried and ground kelp and kelp extracts are common in organic gardening.
kelvin: (K) n. Unit of measurement to express the color (spectrum) of light emitted by a lamp; the absolute temperature of a blackbody radiator having a chromaticity equal to that of the light source (see correlated color temperature).
Kelthane: n. Synthetic insecticide (chemical name: dicofol) used primarily for control of spider mites.
kilowatt: n. One thousand watts.
kilowatt-hour: n. Measure of electrical consumption used by electric utilities and power distributors equal to the consumption of one kilowatt in one hour.
lacunulose: adj. Having tiny holes, as in leaves.
lamina: n., (pl. laminae (-ne)). thin plate or scale. Specifically, in botany, the blade or expanded portion of a leaf or petal.
lamp: n. The illuminated portion of a light fixture, typically consisting of a glass bulb encasing a gas, electrode, and/or filament which emits light when an electrical charge is applied.
lamp life: n. Measure of lamp performance, as measured in median hours of burning time under ANSI test conditions.
lamp lumen depreciation: (LLD) n. Decrease over time of lamp lumen output, caused by bulb wall blackening, phosphor exhaustion, filament depreciation, and other factors.
lamp start: n. Generic term used to describe a lamp’s starting characteristics in terms of time to come to full output, flicker, etc.
leaf: n. Part of a plant that grows along the sides of stems or branches, containing chlorophyll. Ordinarily, leaves are the part of a plant that performs photosynthesis, the process of converting sunlight and carbon dioxide into energy for the plant to grow. It is common for leaves to grow, fall off, and be replaced.
leaf spot: n. General term used to describe various types of foliage diseases that usually result in circular spots on leaves. Usually controlled with well-timed fungicidal sprays. (See anthracnose, black spot, and scab.)
LEO: abbr. Law enforcement officer.
light mover: n. Motorized device which moves an HID lamp back and forth across a track mounted to the ceiling of a grow room to provide more even distribution of the light.
limestone: n. Material worked into soil to alter an acid pH to an alkaline pH.
lime sulfur: n. Caustic pesticide made from calcium polysulfide. Usually used as a spray to control various diseases, including leaf spot, peach leaf curl, and powdery mildew. Also effective against mites, scale, and some other insects.
LST: abbr. Low stress training. Gentle coaxing of plant stems and branches to prevent stress and thus plant damage or hermaphrodism.
lumen: n. The unit of luminous flux in the International System, equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions. Anecdotal evidence suggests that light output of 2000 lumens/sf of growing area is the minimum required for germination and plant growth. Moderate growth will be achieved with 5000 lumens/sf, and optimal growth will be achieved with 7000 lumens/sf or higher.
luminaire: n. Complete lighting unit, consisting of a lamp or lamps together with the components required to distribute the light, position the lamps, and connect the lamps to a power supply. Often referred to as a “fixture.”
lux: n. Standard unit of illuminance. One lux is equal to one lumen per square meter.
male: adj. In botany, having flowers that have stamens only and do not produce fruit or seed. In cannabis cultivation, male plants are typically culled as soon as they can be identified to focus resources on female plants and to prevent pollination. Breeders typically keep one male plant of a known strain in another grow area to selectively pollinate particular female plants.
manicure: n. During cultivation, the removal of excess leaves to focus plant energy on the developing cola. After harvesting, the removal of seeds, stems, leaves, and other elements of the dried cola from the high potency flowers.
marcescent: adj. Of a plant part, withering but not falling off. Plants may be marcescent for many reasons, including nutrient or water deficiency, disease, or pest infestation.
mechanical analysis: n. Physical analysis of soil material to determine its grain-size fraction.
mechanical stability: n. Resistance of soil broken down by mechanical forces like tillage or abrasion.
medicinal marijuana: n. Marijuana smoked or eaten for health-related physiological purposes. Marijuana use has been clinically attributed to decrease in pain from intraoccular pressure in patients with glaucoma, appetite stimulation in patients with AIDS and chemotherapy related wasting, and symptoms of multiple sclerosis, ulcerative colitis, chronic pain, among other contemporary and historical diagnoses. Use of marijuana for medical purposes is legal in some jurisdictions.
mercury vapor: n. Type of high intensity discharge lamp generating light by means of electrical arc in vaporized mercury and emitting light in the red/orange wavelength (approx 2000 degrees K color temp). Mercury vapor lights are commonly used as security lights or to illuminate outdoor areas. These lights are not suitable for growing.
metal halide: n. Type of high intensity discharge lamp generating light by means of electrical arc through a mixture of vaporized halides, and emitting light in the blue/green wavelength (approx 6500 degrees K color temp). Known to enhance “bushiness” and discourage upward growth. Metal halide lights are commonly used in vegetative growth stage , although “enhanced spectrum” lights are sometimes used for all cultivation stages due to additional intensity in the red/orange spectrum.
MH: abbr. (see metal halide.)
midrib: n. In botany, the central vein of a leaf or leaflike part.
mildew: n. 1. A growth, usually whitish in color, produced on living plants by fungus. 2. A fungus that causes such growth. Mildew is typically controlled by lowering relative humidity, standing water, and by separating plants that are touching each other or other surfaces.
miticide: n. Material used to control or kill mites.
magnesium: n. Element found in combination in minerals; in plants, located either in the seeds or in the chlorophyll.
moisture tension: n. Force at which water is held by soil. Expressed as the equivalent of a unit column of water in centimeters.
monovalent cation: n. Ion having a single positive charge.
mother: n. A female plant selected for desirable genetics used as a source for clones.
MV: abbr. (see mercury vapor)
N-P-K: n. reference to relative percentage ratios of 3 basic nutrients in plant fertilizers. N refers to nitrogen, P refers to phosphorus, and K refers to potassium. Roughly equal N-P-K ratios will promote vegetative growth, and higher concentrations of phosphorus will help induce flowering.
neck: n. The narrow, tubular end of the HID bulb, attached to the threads.
negative ion generator: n. Device which creates a cloud of negatively charged ions and distributes this cloud into the atmosphere to bond with positively charged particles in the air, neutralizing their odor effects. Many ion generators appliances are also equipped with a charged metal diode which acts as a conductor to attract airborne particulates for enhanced odor control.
negative pressure: n. Ventilation system designed so that air flows from the corridors into an isolated space, ensuring that contaminated air cannot escape from the isolated to other parts of the facility.
neutral soil: n. 1. A soil that is neither significantly acid nor alkaline. 2. A soil with a pH of 7.0. 3. A soil with a pH of between 6.6 and 7.3.
NIG: abbr. (see negative ion generator)
nitrate of soda: n. Inorganic fertilizer that leaves an alkaline reaction.
nitrification: n. Formation of nitrates and nitrites from ammonia.
nitrogen: n. Element heavily drawn upon by plant crops; usually the first element in the soil to be depleted. Nitrogen (N) is one of the three key ratios in commercial fertilizer.
node: n. Section of plant stem where branching and leafing occur.
nodiferous: adj. In botany, bearing or producing nodes.
nutes: abbr. (see nutrient solution.)
nutrient solution: n. Liquid fertilizers used in both soil and hydroponic operations.
organic gardening: adv. Method of gardening using only natural, unprocessed or unrefined materials as substrate and nutrient supplements. Ash, blood meal, worm tea and castings, and other materials are used in lieu of chemical fertilizers.
organic soil: n. Term applied to soil that consists primarily of organic matter, such as peat, compost, guano, or other natural materials.
orthotropic: adj. In botany, of or pertaining to or exhibiting orthotropism; growing more or less vertically. Under normal circumstances, cannabis plants grow orthotropically.
oxygen: n. Element found in the soil needed by plants for growth, typically absorbed at the roots.
ozone: n. O3. Molecule consisting of three atoms of oxygen. Reactive gas used to neutralize odors by bonding with particulates, making them slightly heavier than the surrounding air and drop out of the atmosphere. Ozone generators are common appliances in grow rooms used to reduce odors, especially during flowering. Effects of ozone gas on humans and plants are debated, although there is officially no known hazard.
palmate: adj. In botany, having 3 or more lobes, leaflets, or nerves radiating from a common point. Cannabis leaves are considered palmate.
PAR lamp: n. Type of halogen with an internal reflector designed for use in a standard A-lamp socket. PAR lamps are not suitable for horticulture.
parabolic reflector: n. lighting distribution control device that is designed to redirect the light from an HID lamp in a specific direction. In most applications, the parabolic device directs light down and away from the direct glare zone.
passive air intake: n. Means of ventilating enclosed spaces without mechanical assistance. (ant. active air intake).
perlite: n. Natural volcanic glass expanded into tough, light granules using high temperatures and used as admixture to increase drainage in dense or poorly draining soils.
pinching: n. Method of pruning plants by removing new leaves or buds at the growth tip to encourage branching or fuller growth. Also sometimes referred to as topping.
integrated pest management: n. An approach to pest control that strives to manage pests at acceptable levels instead of completely eliminating them. It begins with techniques that are least disruptive, such as planting resistant varieties, using biological controls, less toxic sprays and appropriate cultural techniques, and only using traditional synthetic pesticides as a last resort.
pH: n. Measure of relative acidity/base of a substrate, such as water or soil, on a scale of 1-14. A pH of 6.5-7.0 is optimal for water and soil to be used for cannabis cultivation. pH is measured with digital meters and strips and can be altered with the addition of more or less acidic admixtures.
phenotype: n. In botany, the outward form, appearance, and characteristics of a plant, produced by the interaction of environmental and situational factors upon the traits dictated by the plant’s genes. Training, supercropping, and topping are all methods of altering the cannabis plant’s phenotype to increase plant size and yield.
photoperiod: n. Lighting cycle used to mimic seasonal conditions for different stages of growth. 18/6 photoperiod refers to 18 hours of lights on, 6 hours of lights off, and is used to induce vegetative growth, as is no photoperiod (lights on 24/7). A 12/12 photoperiod is used to induce flowering.
photosynthesis: n. Process by which plants build chemical compounds (carbohydrates) from light energy, water and CO2 (carbon dioxide) to use as food.
phototropic: adv. Growth or movement of a sessile organism toward or away from a source of light. Plants illustrate a phototropic response to light which is enhanced in artificial illumination environments. Rel: Heliotropic adv. growth or movement toward or away from the sun.
PO: abbr. police officer. Also, probation officer.
podzolization: n. Process by which soils are depleted of alkaline material and become more acid.
pollen: n. Mass of microspores or grains located on the anthers of seed plants and containing the male gametophytes. In cannabis, only male plants produce pollen.
powdery mildew: n. Fungal disease that causes white or grayish spots or powderylike threads on the new growth of many plants. Traditional fungicidal sprays are the most effective controls. Antitranspirant sprays may also help prevent infection.
PPM: abbr. Parts per million. Measure of minerals or compounds in a solution or mixture of liquid or gas.
quartz halogen: n. (see halogen.)
radical: adj. In botany, pertaining to or growing from the root.
radication: n. Process of taking root or of causing to take root. (ant. eradicate).
radix: n. The root of a plant.
reflector: n. Portion of a light fixture which creates an enclosure around the lamp to distribute light in a desired direction. Many reflectors are also equipped with ventilation sockets.
regenerate: v. To returning plants to vegetative growth after colas have been harvested to increase yields from a single plant.
RH: abbr. (see relative humidity.)
reflectivity: n. Measure of the reflective quality of a surface; the relative ability of a given surface to reflect light away from it without absorbing, diffusing or otherwise compromising the light’s quality, intensity and spectrum.
relative humidity: n. Measure of relative moisture content of air as compared to the total water vapor the air could hold at the given air temperature. Relative humidity is measured with a sling psychrometer or other calibrated device. 65% relative humidity is considered optimal for cannabis cultivation.
rogue: n. Plant that falls short of any predefined standard as compared to others of its genotype, such as size, growth speed, yield, etc.
root rot: n. Name used to describe a disease caused by soil-borne fungi that kill plant roots in overly wet or poorly drained soil with insufficient aeration. Plants turn yellow, individual branches wilt or die back, and entire plant may die. The best control is to improve drainage and cut back on watering. Very few fungicides provide effective control.
rooting hormone: n. Powdered or liquid compound used to induce rooting in plant cuttings.
rockwool: n. Mineral fiber used in horticulture to start seedlings and as a substrate for hydroponic systems.
ruderalis: n. Family of cannabis strains known for negligible concentrations of psychoactive compounds.
sativa: n. Family of cannabis strains known for high THC potency and dense cola formation. Often hybridized with indica strains to create a mixture of desirable characteristics.
scale: n. Large group of insects, so called for their multi-colored shieldlike armor under which they hide and feed. They stick fast to plant stems, branches, and leaves of herbaceous plants, often resembling small bumps or “scales”. Their outer shell makes them difficult to control with insecticides. Infested plants are weakened, grow poorly; leaves are distorted or drop; branches or entire plants can die. To control, encourage or release beneficial insects, handpick, spray with insecticidal soaps, horticultural oils, or traditional insecticides. Sprays are most effective when insects are in the crawler stage. Scale can be effectively removed by hand with the point of a small paring knife.
scale parasite: n. Any of several species of Aphytis wasps used as biological control of some species of scale. They can be purchased through the mail.
scarecrow: n. Object suggesting a human or animal figure used to keep animals from gardens. Inflatable snakes are sometimes used to keep rodents from eating young plants.
scorch: n. Injury to leaves caused by lack of water or excessive transpiration.
ScrOG: abbr. Screen of Green. Technique of growing cannabis employing a screen or grid into which plants are trained to grow to maximize the available space and lighting. (also see SoG).
sexual propagation: n. Propogation using seeds. Sexual propagation introduces genetic variation in characteristics of offspring as compared to parent plants. Also refers to the process of pollination of female flowers.
shake: n. Unpurified hash derived from agitating cannabis leaves and bud fragments on a wood-framed screen to separate trichomes from plant material.
skuff: n. Slang term referring to non-purified hash derived from waste cannabis leaves by one of a variety of agitation methods.
skunk: n. Reference to various strains and hybrids of the cannabis plant that have higher than average odor and other characteristics.
slaked lime: n. Lime that is used to raise the pH of soil but is more caustic than dolomitic soil.
SoG: abbr. Sea of Green. Technique of growing that encourages smaller, more numerous plants to be grown and harvested more frequently in a continuous growing operation. Anecdotal evidence suggests that yields can be higher to roughly equivalent to more traditional methods, but with lower risk of failure and more regular harvests. SoG is also a technique of producing multiple generations of plants quickly for breeding/hybridization purposes.
soil amendment: n. (see amendment).
soil pasteurization: n. Sterilization process of soil that neutralizes harmful organisms without chemically altering the soil.
solarization: n. Process of eliminating harmful organisms in soil outdoors by covering the planting area with clear plastic to raise temperature and decrease access to fresh water.
spider mite: n. Very small spider-like insect that sucks juices from the leaves of many plants. It thrives in hot, dry weather and on dusty, drought-stressed plants. It causes stippled foliage, with a shiny yellow or silver coloration, and often covers the leaves with fine webbing. Infested plants are weakened and often die. Control with beneficial insects, insecticidal soaps, horticultural oils, sulfur sprays, or traditional insecticides
sinsemilla: n. Female cannabis plants cultivated to maturity without pollination from male plants, thus not producing seeds. (From the Spanish “seedless” or “without seed.”)
specular reflection: n. Redirection of incident light without diffusion at an angle that is equal to and in the same plane as the angle of incidence. The specular inserts included in some HID reflectors work on this principle.
steradian: n. Unit solid angle on the surface of a sphere equal to the square of the sphere’s radius. Unit of measure used in calculating lighting intensity.
supercropping: v. Method of increasing yields by tying the top of the plant to its base. Encourages natural branching and multiple colas by de-emphasizing vertical growth. The original growth tip is often removed for cloning or disposal.
taproot: n. 1. Main root of a plant, which grows downward to a considerable depth, giving off lateral roots in succession. 2. The first root to emerge from a germinating seed.
THC: abbr. Tetrahydrocannabinol. The primary intoxicating agent derived from the cannabis plant.
tilth: n. Physical condition of a soil in respect to its fitness to support the growth of a specific type of plant.
trace element: n. Beneficial chemical element found in soil and plant tissue in very small amounts.
training: v. 1. Plant management technique involving the use of frames, rope, twine, or other mechanical means to control the shape of a plant. 2. To bend the main stem into a non traditional shape to avoid detection and to allow lower branches access to light. Esp. important for growers using the SoG growing method, supercropping, and those using fluorescent lights, which must be located very close to plants for optimal growth.
transpiration: n. Loss of water vapor from the surface of plant leaves.
transplant: v. Act or process of removing and resetting, as a plant; transplantation. 2. n. A plant that that has been transplanted. Plants with root systems that have outgrown their containers must be transplanted into new containers to avoid stress, which can lead to hermaphrodism or disease. Transplanting should be kept to a minimum to avoid plant shock.
triacontanol: n. Compound containing aliphatic alcohol, used to promote branching, enhance vegetative growth, and increase yields. Applied as a foliar spray.
trichomes: n. Small deposits of crystallized resin emitted from glands of cannabis leaves. Trichomes are separated from plant matter by the use of various screens and agitation methods and purified into hash.
U: (for universal ) adj. I]Industry code indicating a bulb that can be operated in any position: horizontal, vertical (base up) or any other.
ultraviolet light: (UV) n. light with very short wavelengths outside the visible spectrum.
undergrowth: n. Branches and leaves found on the lowest portions of a plant. Excessive undergrowth is typically trimmed during flowering to promote air circulation and focus plant energy on the developing cola(s).
vegetative growth: n. Cycle when plant energy is focused primarily on increasing its biomass.
vermiculite: n. A light, porous granules of mica expanded by heat. Was once common in horticulture but now most frequently used as building insulation.
vermiculture: n. Culture consisting of composting red worms (Eisenia fetida) acting as primary decomposers of vegetative waste and creating rich organic materials as a byproduct. Worm castings and worm tea are prized in organic gardening.
vascular: a. Referring to a plant’s circulatory system, which consists of, or relates to, the specialized conducting tissues of plants–xylem and phloem–which circulate saps or resin.
viscid: a. Sticky.
watch owl: n. Artificial owl mounted on a post or tree limb to frighten pest rodents and birds from a garden.
water-farming: v. (see hydroponics).
watt: n. International System unit of power equal to one joule delivered through a conductive medium per second. (after Watt, James)
whitefly: n. tiny, white, plant insect that infests many plants, congregating on the undersides of leaves. Whiteflies are particularly troublesome in warm weather and in greenhouses. They cause plants to lose vigor and leaves to turn yellow. Control with beneficial insects, including Encarsia wasps. Horticultural oils, insecticidal soaps, yellow sticky traps, botanical sprays, and traditional insecticides are other control measures.
wood ash: n. Fertilizer containing potash.
worm tea: n. Liquid byproduct of vermiculture high in complex organic compounds and collected for use as plant nutrient supplement.
zinc: n. Trace element present in most soils.