This is a living document and will be updated periodically.
With this glossary we want to offer the Authentic Genetics community our best understanding of some important words and terms we all share and use every day. We’re also including each of our AG varieties in the glossary for easy reference, along with tributes to people we respect as cultural icons.
This glossary is intended as a collaborative communication tool, not a definitive dictionary, and the explanations we give are our own understanding informed by thousands of conversations with other growers over many years. We’re still learning new terms and new ways of looking at things every day, and we hope that everyone who has something to add or to say will get in touch and help us keep improving this community reference.
On the Ph scale that runs 0 through 14, the acidic range is 0 (highly acidic) through 6.9 (almost neutral acidity). See: https://agseedco.com/blogs/news/soil-and-medium-thoughts
A method of growing cannabis by hanging the plants suspended in air with their roots growing downwards and exposed. They are fed with a nutrient solution that is sprayed on them in a fine mist.
This refers to the amount of open space in the soil allowing air to circulate through the soil to plant roots.
A standard propagation method in which a well-developed stem midway up the plant is selected. The stem is cut ¾ of the way through at a 45 degree angle making the cut from the bottom upwards into the stem. Lifting the stem to open and expose the cut, a neutral object like a thin toothpick or skewer is wedged in to keep the cut from closing. The cut is loosely wrapped with moistened but not soaked sphagnum moss. Next this little ball is wrapped using regular plastic wrap and tied off top and bottom with pipe cleaners or twist ties. A normal environment is maintained for the plant. When roots develop inside the plastic wrap the new plant can be cut free and planted. It is an exact replica of the original, the same result that growers get with a clone, but with developed roots before separation.
This refers to a substance with a pH ranging from 7.1 (almost neutral alkalinity) to 14 (highly alkaline). See: https://agseedco.com/blogs/news/soil-and-medium-thoughts
This term describes soil or growing medium additives that can be either organic or mineral, like biochar or perlite, and they are used to change the texture of a soil/growing medium that is too dense or too uniform for proper air and water circulation.
The is the unit used to measure the strength of an electric current and lets you know how many devices you can plug in without overloading the circuit. For example if you have a 20 amp circuit the safest plan is to load it with 10 amps worth of equipment max and 15 is the absolute tops for safety.
(see also stamen)
This is the part of the male flower in which pollen is produced. Many people think it resembles a swollen little banana-shaped organ.
Refers to a large family of over 5000 species of tiny insects with tubular mouthparts that suck vital fluids from the plant’s veins and also transmit plant viruses through those open wounds. These little bugs are power multipliers, with some species giving birth to female offspring that are already pregnant. The sappy secretions they produce (honeydew) are troublesome because honeydew is often a precursor to fungal diseases like powdery mildew and black sooty mold. The Cannabis aphid species (Phorodon cannabis) can be pale yellow, pale green or pinkish-brown and can be seen without magnification in clusters on the underside of leaves and on stems. See our article on the Bhang aphid and HLVd: https://agseedco.com/blogs/news/what-can-the-hop-latent-viroid-teach-us
This is the grouping of undifferentiated cells at the growing tip of a branch or root that divide rapidly and create new specialized tissue. Many growers prefer to clone from the AM feeling that these clones are more vigorous.
Refers to assisted propagation using non-sexual (no male needed) reproduction methods such as cloning and air-layering to produce exact genetic replicas of the parent plant.
- Real, genuine, not copied or false
- Of undisputed origin and provenance
- True to character
Autoflowering varieties go from vegetative to flowering independently of the lighting schedule indoors and independent of daylength outdoors. They are preferred by many indoor growers because unlike photoperiod-dependent varieties they are largely immune to Intersexing (aka herming) from stray light leaks during dark time.
A category of essential plant hormones that among many other critical plant processes regulate movement, fluid transport, root function and flowering.
The angle formed between individual leaf stalks and the stem where they join. In Cannabis the flowers initially develop in the axils, also referred to as a crotch.
Refers to a hybrid plant that has been bred back using seed with one of its parents in order to create progeny that have more of the qualities desired from one original parent or the other. Backcrossing has many applications: it is used to maintain rare varieties, to maintain genetic stability, or to bring out and strengthen desired recessive genetic traits.
A cultural term referring to the compact mass of a mature Cannabis flower
There are many different insects that don’t eat Cannabis plants but love to eat the bugs that do eat Cannabis plants. We call these beneficial insects, and they really are. Insects like ladybugs and lacewings are an indoor (and outdoor) grower’s best friend when it comes to controlling plant predators like aphids, mealybugs and thrips without having to resort to expensive and toxic bioactive chemicals like fungicides.
A generic term referring to fertilizers high in Potassium and Phosphorus and often PGH, enzymes and other ingredients some of which can be helpful but which can too-easily be overused or misused.
This blight on growers of all kinds of plants worldwide starts out as a white powdery film and quickly turns to a fuzzy gray mold that in Cannabis causes bud rot and ruins entire grows overnight if unchecked. It is widespread and can survive for years in nature and is easily transported inside on shoes and equipment. See our article discussing Botrytis and the HLVd viroid https://agseedco.com/blogs/news/what-can-the-hop-latent-viroid-teach-us
(See also Axil)
The tiny pointed shoots that will become flowers that emerge from the Axils where branches join plant stems.
Similar to a scab in people, one function of callus cells is to cover a plant’s wounded tissue while it heals. It also has many uses in plant propagation including a technique called micropropagation where callus is used to grow genetically identical copies of plants with desirable characteristics.
The calyx is the botanical name for the outer protective layer, composed of tiny green sepals or lobes, that surrounds the individual developing ovule or seed. According to Rob Clarke: “Seeds of Cannabis cultivars are often larger and lighter in color than those of spontaneously growing varieties. In addition, seeds produced by cultivars lack the horseshoe-shaped base and a mosaic calyx pattern associated with freely shattering, camouflaged, wild-type seeds.”
Cannabidiol is a primary metabolite of Cannabis and unlike THC, CBD has no overtly psychoactive properties although many applications are now known for CBD in neurological and psychological medicine. The genetic distinction between THC and CBD-dominant Cannabis varieties is well-established and goes back to prehistory in the Himalayas. Medicinal Cannabis plants and Cannabis hemp plants are naturally very low THC but are high in CBD, while Cannabis plants preferred for adult use are high in THC and have correspondingly low CBD concentrations.
See Mel Frank’s “Sarah Jane: for a sweet high-CBD variety:
This term refers to medicinal and psychoactive biochemicals first synthesized by natural Cannabis 100,000 years ago from sunlight, soil and water in the Himalayas. Natural Cannabinoids are proving useful and even the medicine of choice in the treatment and prevention of many conditions and diseases that are so poorly addressed by many pharmaceuticals. Over 130 Cannabis Cannabinoids have been identified and more are being discovered every year.
The levels and relative proportions of cannabinoids found in a specific Cannabis variety or cultivar
This is the scientific classification, or genus, assigned to the plant many call marijuana. Scientists and growers generally recognize three species: Cannabis Sativa, Cannabis Indica, and Cannabis Ruderalis, although some geneticists and growers question the science behind the Sativa/Indica distinction and believe that genetics demonstrate that they are the same species.
This refers to yellowing as a result of inadequate formation of green chlorophyll, most often caused by a nutrient deficiency, but chlorosis can also be due to stress from pH variance, pathogens and toxins.
(See also: OHM’s Law)
Term for the amount of demand placed on an electrical circuit by devices that are presently drawing current from the circuit.
(See also: Mother Plant)
A clone/cutting is an exact genetic copy of the original plant from which the cutting, or clone is taken to be rooted and grown to maturity as an exact duplicate of the original. Cloning is extremely useful and cost-effective when desirable characteristics need to be maintained in expanded production for generation after generation of a particularly desirable original plant.
Refers to the flowering spikes of a mature Cannabis plant. Derived from Spanish “cola = tail” and “colita = ponytail” alluding to the graceful bending and swaying flowering tops of a mature Cannabis plant.
A poisonous alkaloid from the autumn crocus used in plant breeding to induce polyploidy mutations in order to manipulate the plant’s genome.
Cold storage is desirable for Cannabis seeds; otherwise cold air, soil and water are all highly undesirable for Cannabis germination, growth, health and flowering. Cold is also a major cause of intersexing - check out some detailed info here: https://agseedco.com/blogs/news/intersex-inflorescence-in-cannabis
Planting synergistic plants among or near Cannabis plants in order to repel pests or to add economic value. Both indoor and outdoor Cannabis grows have successfully integrated different kinds of companion plantings into their growing space. Many companion plantings are chosen for their role in natural insect and disease control, while others are chosen to take advantage of unused lighted space to produce smaller high-value plants in demand locally like succulents, exotics and ornamentals.
Refers to any mixture of decayed organic matter that is high in available nutrients. To become compost organic matter must undergo decomposition processes that use up the excess nitrogen. Immature compost actually uses up soil nitrogen to power its decay, however, once decomposition is complete a good compost adds essential plant nutrients. See our article: https://agseedco.com/blogs/news/soil-and-medium-thoughts
They are the first leaf-shaped objects that appear as the seedling breaks ground. They aren’t true leaves - more like starter organs. Cotyledons use photosynthesis to power initial root and superstructure growth from nutrients stored in the seed. This is one reason that high quality seeds are important - they are the plant’s entire energy source for the first week or so of growth. Once the plant senses that it’s emerging roots are able to pull nutrients from the soil the seedling puts out its first true serrated leaves that will power all further growth.
Critical Day length:
The correct ratio of light/dark hours to induce flowering in Cannabis.
This occurs when pollen is transferred from the anther of one varietal Cannabis flower to the stigma of a Cannabis flower of a different variety or cultivar.
This is a contraction of “cultivated variety” and refers to a plant derived from a cultivated variety that has persisted under cultivation long enough to be recognized as a distinct variety. The term “Cannabis cultivar” is commonly understood to mean a group of similar Cannabis plants that:
- can be readily distinguished by morphological and physiological characteristics from other Cannabis varieties and
- are of a variety of Cannabis that has been produced by horticultural or agronomic techniques and
- are not normally found in wild populations.
The thin layer of plant wax called cutin is found on the surface of the stalk and stems of Cannabis plants.
The term cutting generally refers to a growing tip cut from a parent plant for asexual propagation. Such cuttings are perfect replications of the mother plant assuming comparable growing conditions and circumstances. While producing clones is the most common use of cuttings, a cut stem can also be grafted onto another Cannabis plant to produce multiple varieties of flower (or pollen) on one plant.
These are a family of plant hormones, complementary to auxins, that promote cell division, direct growth, delay the aging of leaves, and promote photosynthetic processes..
This refers to the biological processes necessary to bring a Cannabis flower from freshly cut to ready for consumption and involves careful management of temperature, humidity, light and ventilation.
Cool and over-wet conditions allow this fungus to thrive and attack emerging seedlings and newly-rooted clones, causing the young stem to rot at its base.
Decarboxylation is the term for transformation of non-psychoactive cannabinoids like THCA and CBDA into the psychoactive and medically active cannabinoids we all know as THC and CBD. Technically the inactive molecules THCA and CBDA have an extra carboxyl ring in their chemical structure and heating the cannabinoid molecule removes that extra ring and “de-carboxylates” the molecule, making it bioactive and fully capable of delivering its benefits.
Species of plants that have the male and female organs on separate individuals.
A BS cannabis term for the unknown source of damage to stems, leaves and flowers. See our article about the HLVd viroid.
Durban Poison S1 Feminized Seeds (by Mel Frank)
This classic variety is fast flowering and easy to grow with an excellent yield. Durban Poison is characterized by dominant tones of spring flowers, garden herbs and sweet citrus with strong hints of earth and moss and occasionally a wisp of lavender.
It is highest in b-caryophyllene, averaging 11.29, followed by terpinolene 10.69, nerolidol-2 8.04, guaiol 6.94, nerolidol-1 6.02, limonene 5.44, a-pinene 4.85, a-caryophyllene 4.76, a-gurjunene 4.51, a-bisabolol 4.43, and linalool 4.23.
Durban Poison and South African varieties are known to intersex, or become hermaphrodite, so keep an eye out and do not breed with any females that do. When a sexually stable female is selected, Durban Poison is an excellent variety to breed with, with an excellent bud structure and 8 to 9 weeks flowering time that make it a useful tool to any breeder. See more: https://agseedco.com/collections/frontpage/products/durban-poison
A bubble of air that gets trapped in the vascular system of a cutting that blocks water and nutrient uptake. This generally happens if too much time elapses between the cutting and immersion in a rooting medium.
An intricate system of cellular receptors and specifically configured molecules found throughout the body that regulate a wide range of functions including pain, sleep, mood, carcinogenesis, memory, appetite, sexuality and reproduction, mental processing, energy reserves, the gut microbiome, and many more. For more details: https://agseedco.com/blogs/news/the-endocannabinoid-system-phytocannabinoid-enriched-hemp-seed-oil-by-todd-mccormick
A broad family of biochemicals responsible for providing the energy that catalyzes the plant’s metabolic processes. Enzymes do this by breaking down the sugars, proteins, fatty acids and other elements that drive the plant’s growth and development. Enzymes are dependent on the proper temperature, moisture and pH in order to function properly, and when enzymatic reactions are interrupted or slowed by external events like a sudden drop in temperature the plant easily goes into energy-deprivation shock.
Refers to the “First Filial” generation, the progeny of the P1 (1st generation parents) plants.
F1 Hybrid Generation:
F1 refers to the heterozygous first filial generation. Heterozygous means a plant that has inherited different forms of a particular gene from each parent. This contrasts with a homozygous genotype, where an individual inherits identical forms of a particular gene from each parent.
F2 refers to the second Filial Generation, a plant resulting from a cross between two F1 plants.
Female Cannabis Flower:
(from: Shilling et al 2020) “The female flower is enclosed within a green leaflike perigonal bract sometimes also described as a sepal, but morphological studies agree that it is a bract. As such, it is not strictly a part of the flower.
Between the perigonal bract and the carpel is a membranous and hyaline perianth which tightly embraces the ovary. It is worth noting that this inconspicuous perianth sometimes is not mentioned in the structure of female Cannabis flowers or is considered missing as it is not visible from the outside of the flower. Most likely, these membranous structures are homologous to sepals.
At the top of the ovary are two filamentous styles. The stigma is brush-like and has epidermal cells elongated into hair-like projections. The commercially interesting phytocannabinoids and terpenes are predominantly produced on the perigonal bracts of female flowers, more specifically in glandular trichomes that cover those bracts.”
Feminized Cannabis seeds are commonly produced by treating the female plant with silver thiosulfate before she begins to set seed, resulting in seeds that are almost 100% female. There are other methods of feminizing including manipulating the photoperiod and the use of colloidal silver or nanosilver, but STS treatment is the most common method. For an outstanding example of feminized seed check out: https://agseedco.com/collections/frontpage/products/durban-poison
The reproductive or flowering stage follows the vegetative stage and is the final part of the Cannabis plant’s growth cycle, which in the unpollinated female leads to harvesting of seedless flower for consumption and in the pollinated female leads to seed production. In the male Cannabis plant the flowering stage leads to pollen production and release.
Foliage Feeding (also Leaf Feeding):
Refers to the process of providing nutrients and other substances applied by spraying the leaves. The sprayed substance is absorbed through the stomata, tiny two-way pores on the lower surfaces of Cannabis leaves that open and close to inhale and expire vapors and liquids, and in response to environmental cues.
This is one of several terms used to refer to the amount of light being sent by or received from a light source, in this case One Footcandle is the amount of light falling on one square foot of surface from a candle one foot away. Mostly used in the US interior lighting circles. Not really very helpful for indoor growers. To convert FC to the more useful Watt (Watts = Foot Candles x 0.01609696)
Refers to the process of flowering and is closely related to “flourishing”. From the Latin florescere (flor-escere): “begin to flower”.
In our experience, a dependable organic growing medium.
A non-technical term that refers to Cannabis flowers that have been cryogenically frozen immediately after harvest, which if done right preserves nearly 100% terpenes and secondary metabolites of the living flower.
A bioactive chemical product of natural or synthetic origin that destroys fungus through contact or translocation.
A chemical product or natural or synthetic origin that inhibits the growth of fungus.
Fungi are plants that don’t photosynthesize - they don’t have chlorophyll so they can’t make their own food from sunlight. They thrive in moist protected environments in the presence of wounded, diseased or dying vegetable matter. Above ground they grow and reproduce by making spores that seek a host plant (or animal), where they implant themselves and then obtain food for growth by secreting enzymes that dissolve and digest their host plant or animal tissue.
Refers to the first stage of a Cannabis plant’s life cycle, which begins with the initiation of active growth by the embryo inside the seed case, splitting it open and allowing the initially hairless embryo root tip to emerge. Still inside the split seed case the cotyledon leaves develop and open as the embryo root extends and develops secondary root hairs and the stem raises up, finally shrugging off the seed case and beginning the transition into the “Seedling Stage” of growth. Check out article on germination: https://agseedco.com/blogs/news/germination-tips
A class of plant growth hormone with many different horticultural applications. GbA is used by Cannabis breeders on females with highly desirable qualities to make them produce male flowers in order to produce feminized seeds with those desirable qualities.
Refers to a class of resin-making glands that, on the Cannabis flower and to some extent its leaves, are principally the Bulbous, Sessile and Stalked trichomes, which along with a subclass of Non-Glandular trichomes all play key roles in making Cannabinoids, Terpenes, Flavonoids, and other secondary metabolites and in protecting the flower and its seed against harmful UV radiation and other environmental stressors.
Cannabis growers use this technique mainly to produce multiple kinds of flowers on a single plant. The term refers to joining plant structures from two different plants, such as joining multiple branches from different plants to a single strong female, or joining the root of one fruit tree with the stem of another, to get fruit, flowers or seed with the qualities of both the graft parents.
Mel got the original GDP seeds in 2012 directly from a Californian named Ken Estes who was widely credited with bringing GDP into the West Coast grower community. The GDP line has been carefully bred and preserved by Mel Frank to this day. https://agseedco.com/collections/frontpage/products/grandaddy-purple
A manufactured or self-made enclosure designed for self-contained cultivation of Cannabis.
Refers to gradually adapting indoor or greenhouse-started plants in trays or containers to the natural outside environment by exposing them to increasingly long outdoor periods before finally planting them out.
Original Haze was first bred in 1969 in the Santa Cruz Mountains by a gentleman named G, who exchanged seeds with Skunkman Sam who saved the variety and turned the world onto Haze.
Todd received the variety directly from Skunkman Sam in 2012 with seeds from the original 3 way Colombian Haze that was first bred in 1969 in the Santa Cruz mountains by Sam's neighbor "G". Sam kept them through IBL breeding since the 70's to preserve the variety.
This variety contains no Afghan/Indica, so there’s not a hint of skunk, making Haze unlike most everything in modern cannabis. Terpinolene dominates the Haze family profile along with significant amounts of b-caryophyllene Linalool, b-Pinene, Limonene and Humulene. The first wave of citrus-dominant, lemon/grapefruit-forward aromas and tastes of classic Haze varieties is quickly followed by a smooth sweet mouthful of sunny herbs and warm spice, and many of the Haze varieties finish with a recognizable peppery hit.
Original Haze is an amazing variety that is uniquely useful for breeding because its presence enhances the dominant and subtle characteristics of other varieties without changing them. It’s a Swiss Army knife of Cannabis genetics - full of useful and surprising tools. There is a lot of variability in the expressed traits of this variety which is what makes it such a fun and interesting plant to breed with.
Some of our favorite variations
Skunk No.1 x Original Haze
Original Haze (Purple Phenotype) x Northern Lights https://agseedco.com/products/original-haze-purple-phenotype-x-northern-lights-2
Superglue x ON Haze
Blackberry Fire x ON Haze
GSC x ON Haze
4G x ON Haze
Banana Split x ON Haze
Blue Cookies x ON Haze
Blue Dream x ON Haze
Dosi Pie x ON Haze
Double Dream x ON Haze
Forbidden Fruit x ON Haze
Gelato 33 x ON Haze
Gelato Glue x ON Haze
GMO Cookies x ON Haze
Gorilla Cookies x ON Haze
Green Crack x ON Haze
Key Lime Pie x ON Haze
Khalifa Kush (OG Kush) x ON Haze
Legend of Zelda x ON Haze
Lemon Cake x ON Haze
Lemon Tree x ON Haze
Lemonade x ON Haze
LG OG x ON Haze
Mochilato x ON Haze
Purple Punch x ON Haze
Romulan x ON Haze
Hemp is a broadly used term with many different meanings but always with Cannabis sativa as the reference plant. Any distinction between Hemp Cannabis and High Cannabis, or however one characterizes the distinction, is manmade. Low THC varieties of Cannabis are bred to be used in the context of “Hemp”, either industrially or medicinally, while high THC Cannabis varieties are bred for their medicinal, psychoactive and pleasurable properties. See our article on hemp seed oil and the ECS https://agseedco.com/blogs/news/the-endocannabinoid-system-phytocannabinoid-enriched-hemp-seed-oil-by-todd-mccormick
Refers to the manifestation of both Male and Female sex organs on a single plant that under average conditions would manifest only one or the other gender identity. See our detailed article: https://agseedco.com/blogs/news/intersex-inflorescence-in-cannabis
High Intensity Discharge lights use electrically-charged Sodium or Mercury/Metal Halide gasses to create a light-emitting plasma with output that’s concentrated near the middle of the visible spectrum and tails off rapidly toward both the Red and Blue ends.
Also termed phytohormones, these organic substances are signaling molecules produced by the plant (or applied by the grower) that regulate its growth and development. (See also PGR - plant growth hormones)
Humidity (Relative Humidity):
(See also VPD)
Relative Humidity refers to the amount of water vapor that the air can hold relative to its temperature. A certain amount of water vapor in cool air creates a higher number than that same amount in warm air because cold air can hold much less total water vapor, so any amount will be a higher % that the same amount in warm air.
This term refers to the decomposing organic matter in soil from which plants draw living nutrients. Plants also draw major and minor elements including metals and salts from decaying minerals. Along with the microbiome, water and air, humus and minerals make up a living soil.
See more details at:
A Cannabis hybrid is a cross between two genetically different Cannabis varieties.
Refers to the greater vitality, higher resistance, and faster development that growers often observe in the progeny of hybrid crosses
A general term for soilless growing technologies. The main technologies are classified as: Wicking, Deep Water Culture (DWC), Nutrient Film Technique (NFT), Ebb and Flow, Aeroponics, and Drip.
Instrument for measuring the amount of humidity or water vapor in an air sample.
Indica and sativa are common classifications of two types of cannabis, which we call varieties, that produce either narrow or broad leaflets. The fact of the matter is, when the taxonomy was being written up in 1753, Carl Linnaeus was essentially aware of only one type of cannabis: the European Hemp variety (Cannabis sativa). It was later in 1785, that the varieties from India (Cannabis Indica) were named by Jean-Baptiste Lamarck.
According to Rob Clarke: “C. indica exhibits much phenotypic diversity across its four putative subspecies but is less genetically diverse yet more heterogeneous than C. sativa; in other words, it has a smaller variety of alleles unevenly distributed among individual populations. This may have resulted from (or was at least encouraged by) adaptive radiation into diverse geographical zones and diversification into myriad geographical races and cultivars (fiber, seed, and drugs). Hillig (2005a) asserts that “the alleles that differentiate C. indica from C. sativa [are] common in the C. sativa gene pool and uncommon in the C. indica gene pool, which suggests that a founder event may have narrowed the genetic base of C. indica. However, a considerable number of mutations appear to have subsequently accumulated in both gene pools, indicating that the indica/ sativa split may be quite ancient.” See our article at: https://agseedco.com/blogs/news/the-end-of-indica-sativa
Term referring to the light/dark ratio required to induce, or bring on flowering.
A more precise term for the vernacular “Herming”, when a single Cannabis plant expresses both male and female flowers either due to random environmental or deliberately induced stress such as treatment with STS. See our detailed article: https://agseedco.com/blogs/news/intersex-inflorescence-in-cannabis
In Vitro/In Vivo:
Refers to horticultural or other experiments done in a lab (plant or animal tissue in vitro = glass) versus experiments done in a living organism (vivo = living plants & animals)
Kush is a term for the group of Cannabis genotypes originating from the Hindu Kush mountain ranges in current-day Afghanistan and Pakistan where this squat, leathery, sedating and elevating plant has been cultivated for thousands of years, primarily as a source of hashish.
Here’s an AG take on Kush: https://agseedco.com/collections/frontpage/products/o-g-kush-x-on-haze
The general term landrace refers to a local variety of a domesticated plant species which has developed largely by natural processes through adaptation to the natural ecosystem in which it lives. The development of a landrace can involve some selection by humans but it differs from a formal variety which has been selectively bred deliberately to conform to a particular formal, purebred standard of traits. Landrace Cannabis varieties are the original genepools from which breeders have created all contemporary Cannabis varieties.
See our comments on Original Skunk: https://agseedco.com/collections/frontpage/products/original-skunk-no-1
As semiconductor technologies have advanced and revolutionized electronics the area of light emitting diode technology has revolutionized Cannabis growing. They are full-spectrum, directional, low energy, low heat, shock resistant, and long-lasting.
What is often mistakenly called an “Albino Bud”, in the belief that it’s an unusual mutation, is almost always a normal bud that has been “light bleached“.
A term for any interruption of the dark cycle with any level or duration of light. Of particular concern for growers during the flowering stage because even a slight or intermittent light leak can can cause intersexing and also reduce flower yield significantly.
LST (Low-stress training):
This refers to simply bending the plant and tying the branches. Since the growing tip of the Cannabis plant dominates its upward growth by inhibiting side stem growth, when the plant is bent sideways the side stems all then have a chance to become growing tips and then flowering tips in their own right.
With over 130 bioactive, medically significant Cannabinoids and hundreds more secondary metabolites including Terpenes and Flavonoids, the Cannabis plant is a natural pharmacopeia that medicine and science are only beginning to explore, although there are thousands of years of human experience with Cannabis and healing. The Cannabinoid profile of medical Cannabis plants can be tailored to meet the specific medical needs of individuals based on emerging selection and growing techniques. Medical Cannabis is also a People’s medicine that anyone can grow for themselves or for loved ones, except in retrograde jurisdictions where it remains illegal.
The Meristem refers to the growing tip of a branch, and the Apical Meristem is the topmost growing tip of a plant. Meristems, or growing tips, are where the most vigorous growth occurs driven by cell division and differentiation, and when a growing tip is removed the plant responds by vigorously putting on side branches - creating multiple new growing tips. Pruning the Apical Meristem is a standard Cannabis pruning technique to encourage development of full side branching with flowering tops and to limit height.
This term refers to elements that are essential for plant growth and development but are needed only in very small amounts.
(see also Dioecious)
The most common form of plant sexual differentiation with both male and female reproductive organs on the same plant.
Refers to a female Cannabis plant with highly desirable traits that is held in vegetative stage by manipulating photoperiod, for the purpose of taking successive generations of clones that replicate her qualities perfectly and bringing them to full flower. A Mother Plant can be grown from seed with carefully selected genetics or grown as a clone from another plant - not necessarily one that was being deliberately grown as a Mother but one that had particularly desirable characteristics.
Mycotoxins are toxic compounds produced naturally by certain types of micro-fungi AKA molds. Aflatoxins are among the most poisonous classes of mycotoxins and are produced by, among others, Aspergillus flavus and Aspergillus parasiticus molds which are unfortunately not uncommon pathogens in Cannabis grows. If not detected and eradicated, Aflatoxin-producing molds can have potentially health-threatening consequences for consumers of the infected flower.
Refers to the multiple joints or junctions on the plant’s stem from which new stem, leaves, shoots, branches or flowers emerge.
Northern Lights (#2)
A combination of Purest Indica crossed with Afghan genetics collected and bred by Seattle Greg.
The NL#2 is a broad-leaved mostly Afghan variety that is quick flowering and covered in fragrant resin. NL#5 has a sweet/floral and slightly citrus profile and is equally quick flowering.
Remarkably NL#2 male flowers are also covered with trichomes and produce the most resin that we have ever seen on male plants. After growing the Chem and the OG Kush varieties for years, we’re confident that NL#2 contributed its genetics to those fantastic cuttings.
You can check out NL#2F2 here: https://agseedco.com/products/northern-lights-2-f2
Northern Lights (#5)
Authentic Genetics received Northern Lights #5 directly from Seattle Greg, who is the same original grower who gave Northern Lights to Nevil and The Holland seed bank back in 1984. Northern Lights numbers #1 through #11 were from mostly Afghan, the #1, also called "Purest Indica", to the "Purest Indica"/Afghan crossed with more tropical/equatorial plants.
Those who like a fast flowering heavy hitting "indica" will not be disappointed growing either NL#2F2 or NL#5F2. These are genetics from the 70s and 80s that some of us old growers and smokers remember quite fondly.
And check out NL#5 F2 here: https://agseedco.com/collections/frontpage/products/northern-lights-5-f2
This extremely common designation has disputed origins and meanings from “Original Gangsta” to “Ocean Grown” and many more, but the designation “OG” simply conveys to us that the named variety is classic, authentic, and traditional.
One of the most famous early days West Coast varieties that stands on its own beautifully and is the basis for ongoing development of many new delicious, aromatic and potent varieties, including several here at Authentic Genetics. It's a dense plant with many ideal traits for indoor growing in limited spaces and is famous for its euphoric, body-vibrating hit and the parallel calm and thought-full mental state it invokes.
See one of our top OG Kush crosses: https://agseedco.com/products/o-g-kush-x-on-haze
Refers to one of the basic equations used in the analysis of electrical circuits. The Law states that the current flowing through an electrical circuit is directly proportional to (1) the voltage (the amount of electricity) being applied to the circuit and (2) the resistance of the circuit’s conductive material, commonly a copper electric wire. The amount of current available in the circuit then tells you how much you can plug into and draw off current to run devices without “overloading” the circuit.
Cannabis has a range of natural essential oils in its flowers and to some extent its leaves that are widely recognized as having medicinal, culinary and industrial applications. These “essential oils” are resin components generated externally in the flower by the trichomes, and are completely separate from the heavier oil extracted from hemp seed, which derives its nutritional, medicinal and industrial value from the embryo within the mature seed.
A term with formal and informal uses, in Cannabis cultivation “organic” most frequently refers to either a non-mineral component of the growing medium, or to cultivation practices that avoid the use of insecticides and fungicides.
Original Haze (100% Columbian):
This variety contains no Afghan/Indica and is unlike almost anything else in modern cannabis. The original 3 way Colombian Haze was first bred in 1969 in the Santa Cruz mountains by a friend of the legendary Skunkman Sam, who has conserved that Original Haze line since and keeps it in pure form to this day. While it takes longer to flower, a grower’s patience will be rewarded with some of the most interesting buds with hints of lemon, spices, and cedarwood in the scent and an unmatched potency that’s famous for having “no ceiling” - meaning the high increases with time! It’s AG’s privilege to be allowed to breed with and offer Skunkman Sam’s original Haze genetics: https://agseedco.com/collections/frontpage/products/original-haze
Original Haze (Purple Phenotype):
A variety of Original Haze with greater likelihood of turning purple and expressing it's colorful flavonoids under favorable environmental conditions. Original Haze is an amazing variety that is best used for breeding. There are many wonderful examples of Haze, but do note that there is a lot of variation in the variety and that is what makes it such a great plant to breed with. Check it out at: https://agseedco.com/products/original-haze-purple-phenotype
Our designation for the result of a back-cross we did with a Nevil’s Haze female and an Original Haze male comes out just a bit more Hazy.
Here’s a purple pheno of Original Haze:
The term refers to crossing, or breeding Cannabis plants with significantly different genetics. Cannabis is a naturally “obligate outcrossing” plant meaning that it is designed by nature to reproduce by spreading its seed widely in order to seek out unrelated plant populations for each successive generation.
The ovary is part of the pistil and contains multiple bundles of tiny immature seeds known as ovules that will develop into mature seeds after pollination.
“Overload” is the term for what happens when electrical circuits crash from having too many devices plugged in. The more devices that are asking for power the more the circuit tries to draw in current from the power grid, working against the resistance of the wire or circuit. This leads to heating and potentially fire, which is why breakers are set inline to disconnect an overloaded circuit from the power grid.
PAR (Photosynthetically Active Radiation):
(See also PPFD)
Refers to the part of the natural light spectrum from 400 to 700 Nanometers that plants are able to use to drive photosynthesis.
Any microorganism, including bacteria, fungi, and viruses, that causes disease, mutation, degeneration or degradation of tissue, organ or function in plants or animals. For a discussion of some important Cannabis pathogens see: https://agseedco.com/blogs/news/what-can-the-hop-latent-viroid-teach-us
Horticultural perlite is made from naturally-occurring volcanic glass “pearls” that contain tiny amounts of ancient water, that are crushed and then flash heat-expanded or “puffed”. Perlite is separated into four grades based upon particle size: super coarse, coarse, medium, and fine.
Refers to all classes of bioactive chemical and biological agents used in the control and eradication of “pests”. Pesticides consist of multiple chemical classes: organochlorines, organophosphates, carbamates, neonicotinoids, pyrethrins and others, each operating on different biological systems in the target ‘pest’, and any other organism impacted, including their neurological, digestive, reproductive, and endocrine systems. Pesticides no longer function like the earliest insecticides and fungicides that were designed simply to kill the organism with highly toxic substances, but today’s pesticides operate instead as endocrine disruptors, DNA mutagens, reproductive teratogens, neurological inhibitors, and through other non-toxic modes of action.
A scale from 0 to 14 that classifies the acid or alkaline balance in a solution or growing medium. From 0 to 6.9 the solution or growing medium is acidic, 7 is neutral (water) and from 7.1 to 14 is considered alkaline. For Cannabis the optimum pH levels for both soil and water are between 6.5 and 6.9. For a detailed discussion on Cannabis & pH see: https://agseedco.com/blogs/news/soil-and-medium-thoughts
“Phenotype" refers to an observable trait or characteristic. "Pheno" means "observe" and comes from the same root as the word "phenomenon" - hence “Observable Type”. Each Cannabis variety has a more or less distinctive phenotype, or collection of physical characteristics resulting from interaction of their genetics with their environment that, taken together, make that variety distinctive. Phenotype refers to characteristics that are visible like overall shape, color, smell and vigor and also invisible characteristics like the variety’s particular cannabinoid and terpene profile and disease resistance.
A class of light receptors in plants that are tuned to the red part of the spectrum. They’re involved in regulating seed germination through a process called photoplasty, the synthesis of chlorophyll, the elongation of seedlings (as anyone who has ever tried to grow under an ordinary light bulb knows), the shape, number, size and growth pattern of leaves, and the timing of flowering.
Refers to day length, which in nature increases and decreases with the seasons and with indoor growing it refers to the hours of light per 24 hour period.
Photon Flux Density:
Refers to the number of photons in the 400-700 Nm range falling per unit of time on a unit of surface - a measure of how much light in the visible range is reaching the surface from a particular source.
The female reproductive organ that is composed of a stigma, style, and ovary. Cannabis pistils are the hair-like structures that emerge as flowers begin to develop and depending on the variety and growing conditions these pistils can be any color of the rainbow. The stigma at the tip of the Pistil captures male pollen and transfers it to the ovary where it fertilizes the ovules to create viable seed.
PGR Plant Growth Hormones:
Growers recognize five types of PGH - auxins, cytokinins, gibberellins, ethylene and abscisic acid. Auxins promote & regulate elongation/growth. Cytokinins promote repair and rejuvenation of plant tissues. Gibberellins are involved in every stage from germination to flowering. Ethylene is heavily involved in the flowering process, and abscisic acid is a critical player in plant vigor, resistance and flowering.
A term for the deliberate design of a plant’s growth structure through physical manipulation techniques including bending, tying, pruning, or grafting. Also refers to the natural growth structure. See also (Phenotype)
A term for a plant’s root system that is restricted by a too-small container.
Refers to a gray-white fungus that propagates from spores that are literally everywhere in the environment. The appearance of PM is triggered by swings in temperature and humidity, especially by nighttime drops in temperature that lead to condensation on the plants which provides the fungal spores a cool, moist, nutritious substrate that promotes rapid attachment, germination and growth. Indoor and greenhouse growers find that maintaining day and night temperatures within a stable range of 65-75 degrees, as well as practicing cleanliness, provides the best protection against PM germination and spread.
For a complete discussion see: https://agseedco.com/blogs/news/powdery-mildew
Photosynthetic photon flux density (PPFD) refers to the amount of energy contained in the light falling on a surface as measured at that surface. PPFD is partly a matter of how energetic the emitting source is and partly how efficiently that energy is transmitted to the surface.
Parts per million is a standard measurement expressing the concentration of a substance in a medium such as air or water. Four drops of orange juice in a 55 Gallon barrel or water would be roughly 1 PPM. One PPM can also be visualized as one inch on a 16 mile long road, or one minute in a two-year journey.
The technique of strategically trimming parts of a plant to stimulate or shape growth.
Purple Kush, a memorable cross of Hindu Kush and Afghan, was first released as a cutting by a San Francisco Bay Area Cannabis company called Trichome Technologies in or around 1995/96. That initial release of PK cuttings was responsible for a lot of the wonderful Purple that has subsequently been bred by Northern California growers and others around the world, creating a whole spectrum of Purple varieties over the years.
See the story at:
This non-technical term refers collectively to the oils, sugars, terpenes, flavonoids, and other substances emitted naturally by the trichome glands of the Cannabis flower. The term also applies to numerous products made with these substances.
Refers to the processes driven by photosynthesis that take place in the leaves. The carbon atoms are stripped off from the inhaled CO2 for use in making sugars, fluids and tissues and the Oxygen atoms are used as energy resources.
The ecosystem of chemical, biological, and physical entities and influences generated, attracted and sustained by plant root growth and activity in the soil/root interface.
According to Rob Clarke “Present-day C. ruderalis, the putative ancestor of extant Cannabis taxa, grows throughout Central Asia and most likely represents a degenerate, inbred, and unselected hybrid blend of various Cannabis gene pools that survived as feral escapes, rather than direct descendants of the now long-extinct ancestral population in its original home.” Ruderalis is highly adapted to shorter Northern latitude seasons and day lengths so it is very quick to flower, which is why it plays a role in the genetics of many ‘autoflowering’ varieties.
This devastating Cannabis predator emerges as tiny worm-like larvae that mature into 4-legged mites. They are microscopic and can only be seen with 90x or better magnification. Generally beginning low on the plant, they work upwards and cause leaf margin downward curl and browning that can be mistakenly attributed to nutrient deficiency, light burn, and other causes. They can be controlled by time-release predatory mites, but can easily become widespread before being detected, and without careful scouting can be missed. For a discussion of how Russet Mites can be mistaken for the Hops Viroid see: https://agseedco.com/blogs/news/what-can-the-hop-latent-viroid-teach-us
Rust fungus produces asexual spores that settle on the leaves of a Cannabis plant and attach themselves by growing a "germ tube" down into the leaf, which anchors itself there to suck up nutrients for the growing fungus above. After about 10 days the fungus is fully grown and then it erupts with spores, sending millions of little ones off to attach themselves to nearby leaves where they begin sucking out nutrients and the cycle repeats until interrupted.
Literally means “to cultivate” or that the plant is beneficial. According to Rob Clarke: “ C. sativa circumscribes hemp landraces from Europe as well as Southwest and Central Asia and is more genetically diverse than C. indica at the species level, while it is also more genetically homogenous than C. indica at the individual plant level (Hillig 2005a); in other words, C. sativa possesses a greater variety of alleles (diversity) spread throughout the majority of individuals (homogeneity), while C. indica possesses a lesser variety of alleles, with much of this genetic diversity restricted to individual, geographically isolated sub- species.
This may indicate that C. sativa descended directly from its hypothetical PHA ancestor population with little differentiation into geographical races and varieties (Hillig 2005a) and spreading easily from its putative Pleistocene refugia in the Balkan and Caucasus Mountains and radiating across the relatively small and geographically uniform early Holocene European and Central Asian landscape.” For AG’s take on the Indica/Sativa discussion see: https://agseedco.com/blogs/news/the-end-of-indica-sativa
The upper part of the union of a graft.
Scrogging (Screen of Green):
Scrogging is a technique for producing more buds and higher yields
by training the individual branches of Cannabis plants onto horizontal screens, webs or frames to create an even one-level canopy. This allows light energy (the Photon flux) to reach all the leaves and flowers equally and provides good air flow and ventilation which are especially critical during flowering. Scrogged plants are said to be more reachable for maintenance and there is far less opportunity for mold and other fungus to take hold and grow.
Sea of Green (SOG):
“The Sea of Green came about in the mid-1980s, supposedly originating in Holland as a commercial growing technique to bring decorative flowers to market quickly and easily. Some enterprising cultivators thought to apply the process to marijuana and before long, indoor gardens flourished.”
“The actual undulating green sea is the end product of a three-step process. The first step is Mothering. A Mother Plant is the source for clones and the keeper of the family genes. She lives by herself under 18-to-24 hours of light per day and can live as long as her root space will allow her to flourish, perhaps years and years. The second step is cloning, taking cuttings from Mother, rooting them in another room and then quickly growing them into short bushes. The final step is forcing the clones to flower in a room filled with other flowering clones in various stages of budding.” From Todd McCormick “How To Grow Medical Marijuana”
The term refers to every biologically active substance produced by the Cannabis plant other than its Primary Metabolites THC and CBD (and their precursors THCA and CBDA), although many would argue that there are additional Primary Metabolites among the Terpenes and Flavonoids.
“Store seeds in small containers and include a desiccant; clean, dry seeds remain viable at refrigerator temperatures for easily 20 and more years. High temperatures, temperature swings, and high humidity are ruinous for seeds. For very long term storage, glass or metal containers are recommended by seed archivists, but I've used film canisters with great success.”
“Do not store in baggies as these may leak or break, particularly if taken in and out of storage. Most plastics actually “leak” after time, but film canisters are especially tough and impermeable and keep contents reliably dry. Storing seeds in plastic baggies is particularly bad.” (From: Storing Seeds by Mel Frank) https://agseedco.com/blogs/news/storing-seeds-by-mel-frank
Selfing (Self-Pollination) S1:
When a Cannabis plant is allowed or caused to have both male and female organs and the male pollen is used to pollinate the female flowers so that the resulting seed is “feminized” and will produce only female plants.
The tiny green structures, botanically classified as modified leaves, that surround and protect the flower bud as it develops.
Sexual reproduction means male pollen merging with female ovules to produce seeds that will germinate and produce the next generation of plants that will have the characteristics of both parents.
Of all the varieties that we grow at Authentic Genetics, "Skunk" has to be the most requested and also the least understood. Many people think it is a variety, when in reality, it is more of a description of one of the many distinctive scents of cannabis found in Afghanistan, Pakistan and the Hindu Kush mountains. While there are no skunks in Asia or Europe, the combination of thiols and myrcene profiles of certain Afghani varieties makes them immediately reminiscent of a skunk spray to anyone who has ever encountered the animal that is only found in The Americas.
Refers to the legendary Skunk #1 developed by Skunkman Sam in the 1970's, and it remains a relatively stabilized, true breeding hybrid in 2022. In 1988 the widely respected writer and breeder Mel Frank received Skunk No.1 seeds directly from Skunkman Sam and reproduced them continually for 8 years until 1996. Then Mel Frank properly stored and preserved them until 24 years later in 2020, their acrid terpene phenotypes were revived by Todd McCormick of Authentic Genetics, which remains the sole source of this direct line of original Skunk No. 1 genetics. See AG’s Afghan x Colombian Gold x Acapulco Gold
Skunk #1 x Northern Lights #2:
This is an absolutely classic combination of genetics first brought together in the 1980s by the Holland Seed Bank when Nevil crossed the Skunk #1 and NL#5. Authentic Genetics initiated the use of Northern Lights #2 as the male, which is completely Afghan. Read more about Skunk at: https://agseedco.com/blogs/news/cannabis-confusion-the-history-of-afghan-skunk
The light spectrum that’s relevant to Cannabis photosynthesis lies between the 400 and 700 Nanometer wavelengths. Energy below 400 Nm falling on a Cannabis plant tends to cause elongation due to energy deprivation and energy above 700 Nm is progressively damaging to leaves and especially flowers.
Stalked Glandular Trichome:
Of the three principal Cannabis trichomes this little bulb on a stalk is a principal THCA factory whose rich secretions also contain all of the Cannabinoids, Terpenes and other secondary metabolites that ooze from the Cannabis flower.
Term for the male Cannabis reproductive organ which consists of the pollen-producing organ the Anther plus the thin vein that feeds nutrients to the organ.
This term refers to a flower in which there are only male reproductive parts present.
This is the organ at the tip of the flower’s pistil which receives the pollen and transports it to the ovaries for pollination of the ovules.
Small pores on the underside of leaves that “breathe” and are responsible for uptake, transpiration, and waste removal along with other life functions. The stomata open and close to receive water, air, nutrients, and anything else deposited on the underside of the leaf’s surface and to help rid the plant of metabolic toxins. The millions of stomata in every Cannabis plant must be kept very clear for them to be able to function properly.
In botany: “All the descendants produced from a common ancestor that share a uniform morphological or physiological character.” “Strain” is a popular but technically mis-applied term for a cannabis variety or cultivar. A cultivar is generally understood as a Cannabis plant that is produced and maintained by growers but does not normally produce true-to-seed; whereas, a variety is a group of Cannabis plants within the species that have one or more distinguishing characteristics and usually produce true-to-seed. None of these “distinctions” are quite distinct enough because the terms overlap and are not precise.
A popular term for the rapid elongation of the plant immediately after the photoperiod goes to 12/12 to induce flowering.
Refers to the surface or the material on which an organism lives and grows and from which the organism may obtain nutrition, information, energy and life support.
A common name for any fertilizer high in phosphorus and potassium that’s intended to promote Cannabis flower formation and growth.
The single root that emerges from the seed casing and grows downwards seeking water and nutrients, quickly developing secondary anchoring roots and hundreds of fine side roots.
In biology, a system for classifying and arranging plants and animals into various groupings according to their biological relationships. While somewhat arbitrary, there are seven main ranks defined by the international nomenclature codes: kingdom, phylum/division, class, order, family, genus, and species.
In Cannabis, terpenes are chemical compounds, produced by specialized glands in the flower, that due to variations in varietal Terpene profiles are largely responsible for the distinctive flavor and smell of each variety. Terpenes/terpenoids also have a wide range of biological and pharmacological activities. Cannabis terpenes with antifungal, antiviral, anticancer, anti-inflammatory, antihyperglycemic, antiparasitic, antioxidant, and antimicrobial properties include myrcene, limonene, pinene, linalool, terpineol, caryophyllene, phellandrene, ocimene, camphene, guaiol, α-humulene, γ-terpinene, β-elemene, nerolidol and citral among many others.
THC is without doubt the Cannabinoid first responsible for human discovery of the Cannabis plant, and THC’s most attractive properties are only available once activated by heat. This suggests some interesting possible origins of the discovery. Once activated by heat this single molecule is then responsible for a significant portion of both the psychoactive and medicinal potential of the Cannabis flower along with its primary partner CBD.
When heat is applied to a fresh Cannabis flower, in all the THCa cannabinoids a carboxylic acid group is driven off and the THCa molecules are therefore “decarboxylated”, which means that chemically the THCa is converted by heat to delta-9 THC.
Thio: from Greek for sulfur, combined with alcohol = thiol.
Thiols are alcohols where oxygen atoms are replaced by sulfur atoms. In the Cannabis culture Thiols are responsible for the intense skunky smells in some varieties that so many seek out and appreciate while so many others avoid them at all costs. However, thiols play a complex and critical part in cellular processes, immunity and resistance, growth, flowering, and reproduction of Cannabis, so like skunks or not you gotta love Thiols!
The process by which a plant expels waste gasses and vapors through its under-leaf stomata.
Refers to restricting a plant’s growth and altering its shape and size by manipulating and tying the stem and branches to a mesh or screen
A class of resin-making glands that, on the Cannabis flower, are principally the Bulbous, Sessile and Stalked trichomes, which along with a subclass of Non-Glandular trichomes, all play key roles in making Cannabinoids, Terpenes, Flavonoids, and other secondary metabolites and in protecting the flower against harmful UV radiation.
Leaves that have been removed throughout growing and at harvest. With the development of new recovery technologies these formerly waste byproducts of flower production can now yield valuable additional product for growers.
A more accurate term used by informed growers to refer to what are too commonly called “strains”.
Refers to the principal ‘veins’ in the plant's circulatory system that transports fluids throughout the stem, roots, branches, leaves and flowers.
The vegetative stage of cannabis follows the Seedling Stage and precedes the Flowering Stage. It is when the plant undergoes all of its primary stem, branch and leaf development before entering the reproduction cycle. Growers are learning that encouraging full vegetative development isn’t necessarily the best strategy for optimum flower yield.
A non-living entity consisting of fragments of RNA code without the protein shell of a virus and, unlike viruses, are only known to infect plants. For details on the dangerous HLVd viroid see our article: https://agseedco.com/blogs/news/what-can-the-hop-latent-viroid-teach-us
A term for an entity that consists of a bundle of genetic code, either DNA or RNA, surrounded by a protein shell. Generally regarded as non-living and without any cellular structures, viruses cannot replicate without embedding themselves inside living cells and harvesting parts of the cell to accomplish their replication. In the process of taking what they need they leave behind a trail of cellular destruction that we call disease. Unlike parasites, which draw energy from their host without killing it, viruses have no such agenda. They enter the cell past its defenses, grab what they came for, replicate, and move right along, replicating exponentially as they go.
Vapor Pressure Density is based on the idea that at any given temperature the air can hold a certain amount of water vapor before it gets saturated and begins precipitating out. Knowing your VPD allows you to balance both temperature and humidity for a perfect VPD that encourages transpiration in your plants.
The VPD number indicates the % of water vapor (humidity) that’s present at the current air temperature. For example, in a grow room with an air temperature of 65 degrees, a VPD of 80 would mean that the air is 80% saturated at that 65 degree temperature. If the temperature goes up to 70 the saturation point of the air is now higher, so if humidity remains the same the VPD number will be lower.
“Room temperature” 70-80°F (21-27°C) water is critical for plant health.
A compound that reduces the droplet size and lowers the surface tension of the water making it “wetter” - more easily transported through the stomata. Biodegradable liquid dish soap is a good wetting agent used by some growers in hard water areas.
Most commonly due to water deprivation but the characteristic loss of rigidity and drooping of plant parts can also be caused by many different plant diseases.
Vascular tissue that transports water, nutrients and minerals from the roots and sugars, lipids, gasses and proteins from the leaves and roots throughout the plant.