• Categories
• Planta de semillero
• Cannabis (Medicamento, droga)
• Cannabis
• Horticultura y jardinería
• Botánica

Citation preview

Cannabis cultivation This article may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (June 2009) Typical home-grown organic sinsemilla bud compared to a cigarette pack. This article presents common techniques and facts regarding the cultivation of t he flowering plant cannabis, primarily for the production and consumption of mar ijuana buds. Cultivation techniques for other purposes (such as hemp production) differ. A basic description of hemp cultivation can be found in the US propagan da film Hemp for Victory. Contents * 1 History * 2 Botany * 3 Cultivation requirements o 3.1 Growth medium o 3.2 Warmth o 3.3 Light o 3.4 Water o 3.5 Nutrients * 4 Stages of development o 4.1 Germination o 4.2 Seedling phase o 4.3 Vegetative phase o 4.4 Pre-flowering phase o 4.5 Reproductive/Flowering phase * 5 Outdoor cannabis cultivation o 5.1 Detection * 6 Indoor Cannabis Cultivation o 6.1 Supply of light o 6.2 Control of the atmosphere o 6.3 Popularity o 6.4 Housing damage * 7 Harvesting, drying and curing o 7.1 Drying o 7.2 Curing o 7.3 Hash + 7.3.1 Hash oil * 8 Pests * 9 Advanced cultivation methods o 9.1 SOG o 9.2 SCROG o 9.3 Hydroponics * 10 Genetics o 10.1 Selection of mother plants o 10.2 Feminized seeds o 10.3 Hybrid vigor * 11 Vegetative propagation (cloning) o 11.1 Humid environment * 12 See also * 13 References * 14 Further reading * 15 External links [edit] History Evidence found in ancient burial sites indicate that humans have been experiment

ing with cannabis spiritually and medicinally since at least the 3rd millennium BC.[1] Herodotus, an early Greek historian, described how the Scythians of the M iddle East used cannabis in steam baths.[2] The status of the plant has changed in recent years. In the early 20th century the US outlawed cultivation, consumpt ion and trade of all cannabis species due to a mixture of reasons, including rac ism, business interests and concerns for human health. Thereafter the vast major ity of states have followed a similar paradigm, imposing penalties that range fr om a small fine to incarceration and execution.[3][4] [edit] Botany See also: Cannabis (drug) Autoflowering hybrid AK47. Cannabis belongs to the genus Cannabis in the family Cannabaceae and includes th ree species, C. sativa, C. indica, and C. ruderalis (APG II system).[5] It is ty pically a dioecious (each individual is either male or female) annual plant (lif e period: April-September). [6][7][8] C. sativa and C. indica generally grow tall (some varieties reach 3 m) and their females start the production of flowers rich in THC (1% to 20%) as the season c hanges from summer to autumn. C. ruderalis is very short, produces only trace am ounts of THC and flowers independently of the photoperiod and according to age.[ 9] However, commercial cross-bred hybrids containing both ruderalis, indica and/ or sativa genes exist (usually called autoflowering), the "low rider" being the most famous. Such breeds are considered advantageous by some growers due to thei r discreet size and short growing periods.[10] See also: cannabis strains. [edit] Cultivation requirements In order to prosper, cannabis needs the following: [edit] Growth medium Almost always soil is deployed, although some advanced growers use hydroponics. An ideal soil for cannabis has the following characteristics:[9][11] * Loam texture to ensure good drainage, which facilitates nutrient absorptio n and prevents root drowning. * Sufficient nutrients. Commercial soil bags usually indicate as "N-P-K = x% -y%-z%" the percentages of the fundamental nutritional elements, i.e. Nitrogen, Phosphorus and Potassium. Nutrients are often provided to the soil via fertilize rs but such practice requires caution. * pH between 6.0 and 7.0. This value can be adjusted - see soil pH. Commerci al fertilizers (even organic) almost always make the soil more acidic (decrease its pH). [edit] Warmth The optimal day temperature range for cannabis is believed to be 24 to 30 °C. Te mperatures above 31 °C and below 15.5 °C seem to decrease THC potency and slow g rowth. At 13 °C the plant undergoes a mild shock, although some strains have bee n observed to withstand frost temporarily.[9][11][12] [edit] Light Light can be natural (outdoor growing) or artificial (indoor growing). When artificial light is used, from the germination until the flowering stage, t he plant typically remains under a regime of 16 - 20 hours of light and 4 - 8 ho urs of darkness. When the plant reaches the flowering stage the regime is typica lly switched to 12 hours of light and 12 hours of darkness. [edit] Water Watering frequency and amount is determined by many factors, including temperatu

re and light, the age, size and stage of growth of the plant and the medium's te xture. A conspicuous sign of water problems is the downward wilting of leaves.[1 3] [edit] Nutrients Fertilizer burn on a leaf Nutrients are the food of plants and come in the form of fertilizers which can b e chemical or organic, liquid or powder and may contain several elements (see al so: fertilizer). Commercial fertilizers must indicate the levels of NPK (mention ed above). During vegetative stage cannabis needs more amounts of N than of P an d K while during flowering P is more essential than N and K. The presence of sec ondary nutrients (Calcium, Magnesium, Sulfur) is recommended. Also there are sev en micro nutrients (Iron, Boron, Chlorine, Manganese, Copper, Zinc, Molybdenum) that are not extremely important and rarely manifest as deficiencies. Fertilizers although vital for good cannabis growth, must be used frugally other wise they could burn the plant. As a general rule, half the amount suggested in a bottle may be given each time.[14] As a plant acclimatized to virtually every growing region on Earth, its nutrient needs vary widely with its genetics and can truly only be determined with exper ience. Chemical plant foods vary greatly maker to maker, and some can be used at full strength, or the strength listed for plants with large fruits like the tom ato. [edit] Stages of development [edit] Germination C. indica seeds File:C. sativa seeds closeup.jpg C. sativa seeds Duration: 12 hours to 8 days. Warmth, darkness and moisture initiate metabolic p rocesses such as the activation of hormones which in turn trigger the expansion of the embryo within the seed. Then the coating cracks open and produces a small embryonic root that begins growing downwards due to gravitropism, if placed in a proper growing medium. Soon (after 2–4 days) the root is anchored and two circ ular embryonic leaves (cotyledons) emerge in search of light, as the remains of the seed shell are pushed away. This marks the beginning of the seedling stage. Seeds may be germinated by soaking them between wet paper towels, in a cup of wa ter at room temperature for 24 hours, or in wet peat pellets. Regardless of the method used however, distilled water is often employed since it has the proper p H. In most cases tap water is sufficient. Peat pellets are often used as a germi nating medium as they make it unnecessary to transplant the fragile seedlings; t he saturated pellets with their seedlings can be planted directly into the inten ded growing medium with a minimum of trouble and effort, or shock to the plant. A technique that achieves high germination rates is the following: First the see ds are inserted into a cup of water. All will initially float over the surface s o forcing them to immerse completely is recommended. Then the cup is left in a w arm dark place for no more than 24 hours (otherwise seeds might drown). Shortly most will go down the bottom, an indicator that water has penetrated the shell. Finally, the seeds are placed carefully in a constantly damp, warm and dark envi ronment such as wet cotton or towel. Dirty hands (even traces of nicotine on the m) can damage the seeds. As soon as the root can be distinctly seen, the seeds a re ready to be placed in a growing medium. [edit] Seedling phase A very young C. sativa seedling. The tips of the first two true leaves are emerg ing between the two round seed leaves (cotyledons) Duration: 1–4 weeks. The seedling stage begins when the seed breaks and exposes

its round “seed leaves” or cotyledons. This is the most fragile time during the entire life cycle of the cannabis plant. It is important to keep a constant atmo sphere with a high humidity level and medium to high light intensity. Most indoo r growers use compact fluorescents or T5 fluorescents during this stage as they give off little heat. HPS and MH lights give off large amounts of radiant heat a nd increase the rate of transpiration in the plant. Seedlings have small root sy stems and can dry out very quickly, thus keeping the medium moist is important. The plant can begin to sex itself in this stage but if time is an issue one can induce sexing by switching to a 12/12 hour period. Once sex is determined you ca n remove the males and switch the cycle back to vegetation stage by inducing an 18/6 hour period. [edit] Vegetative phase A young male cannabis plant during early flowering stage Duration: 1–2 months indoors. In this stage the plant needs all the light (at le ast 18 hours) and nutrients (food) it can get. It will continue to grow upwards and produce new leaves. The sex is starting to reveal which is a sign that the n ext stage begins. Concurrently the root system expands downwards in search of mo re water and food. Some newly developed strains (auto flowering hybrids) omit th e vegetative stage and pass directly from seedling to pre-flowering. When the plant possesses 4 sets of true leafs and the 5th is barely visible in t he center of the growth tip, or shoot apical meristem (SAM), the plant has enter ed the vegetative phase of growth. During the vegetative phase of growth, the pl ant directs its energy resources primarily to the growth of leaves, stems, and r oots. A strong root system is imperative, as it is required for strong floral de velopment. A plant needs 1 or 2 months to mature before blooming. The plant is r eady when it has revealed its sex. The males are then usually culled when they a re identified, because if males are allowed to pollinate the females, the potenc y of the female flowers will be greatly reduced, as energy that would have been used to make large, potent buds instead goes to making seeds.[15] During the vegetative phase of growth, cultivators generally employ an 18 to 24 hour photo period, as the plants grow more quickly if they receive more light, a lthough a warmer and cooler period are required for optimal health. While no dar k period is required, there is debate among cultivators as to whether a dark per iod is beneficial, and many continue to employ a dark period. The amount of time to grow a cannabis plant indoors in the vegetative stage depe nds on the size of the flower, the light you use, the size of the space you're f lowering in and how many plants you wish to flower at once and how big your stra in gets in 'the stretch' - the first two weeks of flowering. Marijuana cultivators employ fertilizers high in nitrogen and potassium during t his stage, as well as a complete micro nutrient fertilizer. The strength of the fertilizer is gradually increased as the plants grow and become more hardy. The modification of a plant's growth habit is called training. Indoor cultivator s employ many training techniques in order to encourage shorter plants and dense r canopy growth. For example, unless the crop is too large to be extensively pru ned, cultivators will remove adventitious growth shoots, often called suckers, t hat are near the bottom of the plant and/or receive little light and will produc e poor quality buds. Many cultivators also employ other techniques: Topping Is done by removing the top of the apical meristem (dominant central stem), call

ed the apex or terminal bud, in order to transfer apical dominance (the tendency for the apex to grow more rapidly than the rest of the plant) to the shoots ema nating from the two nodes immediately beneath the pruning cut. This process can be repeated on one or both of the two new meristems, when they become apically d ominant, with the same results. This process can actually be repeated almost inf initely, but over-diffusion of apical dominance will produce smaller, lower qual ity buds, so it is usually done no more than a few times. Topping also causes mo re rapid growth of all of the branches below the cut while the plant heals. Pinching Pinching (also called super cropping) is similar to topping in that it causes th e lower branches to grow more rapidly, but the apical meristem will maintain api cal dominance, which is especially useful if the plant has already been topped. Pinching is performed by firmly pinching the apical meristem(s) so as to substan tially damage vascular and structural cells but without totally breaking the ste m. This will cause the lower limbs to grow more rapidly while the pinched tissue heals, after which time the stem will resume apical dominance. LSTing LST stands for Low Stress Training and is another form of supercropping, many ti mes referred to as LST super cropping. This technique involves bending and tying the plants branches to manipulate the plant into a more preferred growth shape. This method of training works very well for indoor growers who need to illumina te their plants using overhead lights. Since light intensity greatly diminishes with increased distance (Inverse-square law) LSTing can be used to keep all grow th tips (meristem) at the same distance from the light and can achieve optimal l ight exposure. LST can be used in conjunction with topping, since topping increa ses axial growth (side shoots), topping is often done a few weeks before beginni ng LSTing. LSTing works by changing the distribution of hormones, more specifica lly Auxins, in the plant. Low Stress Training was introduced in 2001 by member D elta9420 at the website TheGardensCure.com (known then as Hempcultivation.com) h ttp://www.gardenscure.com/420/training-scrog-sog-supercropping-etc/39670-delta94 20s-low-stress-training-lst-example.html [edit] Pre-flowering phase Duration: 1 day to 2 weeks. Also called 'the stretch'. In most plants will last for 10–14 days after switching the light cycle to 12/12. The plant development i ncreases dramatically, with the plant doubling in size or more (see reproductive development below). The production of more branches and nodes occurs in this st age as the structure for flowering is built. The plant will start to show calyx which appear where the branches meet the stem (nodes). Pre-flowering indicates t hat the plant is ready to flower. [edit] Reproductive/Flowering phase The flowers of a male cannabis plant Duration: 4–16 weeks. The sex is clearly revealed. Males produce little balls cl ustered together like grapes. Most plants (except auto flowering strains which f lower independently of photo period) will flower under diminished light. In natu re, cannabis plants sense the forthcoming winter as the earth turns and daylight reduces in duration (see also season). If females are not pollinated (fertilize d by male pollen) they will start to produce buds containing sticky white resin glands or trichomes in a final attempt to attract male pollen. The trichomes con tain the largest amounts of THC and CBD, the two main psychoactive substances. I ndoors, flowering is induced by keeping the plant in complete dark for 12 hours every day, until it is ready to be harvested. If manipulated, a female can eithe r generate a seedless bud, a bud with a few seeds, or a bud that is almost total ly seeds. The first case is achieved by removing all the male plants before any of their flowers open, the second occurs when one or more male flowers have bare

ly burst open and then removed and the third case occurs if the males are let to fully pollinate the females. Buds of the first case are called sinsemilla (it is really two words: "sin semil la," which translates to "without seeds" in Spanish, but is often misspelled as one word). The resultant cannabis contains the most Cannabinoids possible[citati on needed]. The amount of Cannabinoids in sinsemilla is considerably more in com parison to cannabis that has been grown in a pollinated environment, because the production of seeds requires an immense amount of energy, and if left unpollina ted a female plant will divert all her energy to calyx production in an effort t o seize pollen.[citation needed] This is especially desirable, as the calyx is w here the highest concentration of trichomes exists, and the more densely packed a plant is with calyces, the greater psychoactive effect that plant will likely have. Potent sinsemilla is especially important to medical users, to minimize th e amount of cannabis they must consume in order to be afforded relief. Cannabis with seeds is generally considered to be of inferior quality and/or grown with i nferior technique. Common terms for seeded, or otherwise low-quality, cannabis a re "mids," schwag, "regs," "booty,", "greta" or mersh. Indoors, plants like cannabis are induced into flowering by decreasing its photo period to at least 10 hours of darkness per day. Traditionally most growers cha nge their plants lighting cycle to 12 hours on and 12 hours off. This change in photo period mimics the plant's natural outdoor cycle; with up to 18 hours of li ght per day in the summer and down to less than 12 hours of light come fall and winter.[16] While the flowering hormone in most plants (including cannabis) is present durin g all phases of growth, it is inhibited by exposure to light. To induce flowerin g, the plant must be subject to at least 8 hours of darkness per day; this numbe r is very strain-specific and most growers flower with 12 hours of darkness to b e safe. The flowering hormone is very quickly inhibited, taking less than two mi nutes of exposure[citation needed]. Flowering usually lasts from 45 to 90 days indoors. If growing outdoors it may t ake somewhat longer, depending on the natural onset of the colder seasons. The f lowering length is mainly genetically determined with plants (as pure cannabis " indica" strains) flowering in as low as 45 days, while plants (as cannabis "sati va") can take up to 4 months to finish and the harvest yields significantly less . This is also the main reason why certain plants (as cannabis indica) are almos t always grown indoors (unlike cannabis sativa, which is also grown outdoors). Some plants, specifically members of the subspecies Ruderalis, will begin the fl owering cycle without a significant reduction in their photo period. Flowers from certain plants (e.g. cannabis) are called Calyx, and are (with cann abis) the most prized part of the plant. In late flowering the calyx are easily visible to the naked eye. Calyx development begins approximately 1–2 weeks after the photo period is reduced. In the first weeks of flowering a plant usually do ubles in size and can triple. Calyx development ends around 5 weeks into floweri ng and is proceeded by a period of Calyx “swelling”. During this time the buds g reatly increase in weight and size. [9] [11] [edit] Outdoor cannabis cultivation Guerrilla cannabis plot in a forest clearing Aerial view of guerrilla cannabis plot A chart demonstrating the reflective qualities of cannabis in comparison with ot her common plants, which may be used for cover. Cannabis can be planted outdoors under the sun, either on natural soil or in pot

s of pre-made or commercial soil. In most places of the subtropics cannabis is g erminated from late spring to early summer and harvested from late summer to ear ly autumn. Outdoor cultivation is common in both rural and urban areas, with outdoor cultiv ators tending to grow indica-based strains due to their heavy yields, quick matu ring time, and shortness. Some growers prefer sativa because of its clear-headed (cerebral) high, better response to sunlight, and lower odor emissions. One can cultivate on his own property or practice guerrilla farming i.e. plant c annabis in remote areas such as forest clearings or mountain cliffs and visit ra rely. However such a method is prone to ripoffs - so much so that some ingenious growers even attach pots on trees to decrease this possibility.[citation needed ] When cultivated outdoors, the chosen areas are those which receive twelve hours or more of sunlight in a given day. In the Northern Hemisphere cannabis seeds ar e typically planted in late May or early June, so the plants can have a full fou r months of growth. Typically, the plants are harvested anywhere from mid Septem ber to early October. In North America, northern locations are preferred (North Coast of California and British Columbia being particularly notable), but southe rn locations (such as Maui, Hawaii) are also known to be good producers.[citatio n needed] In instances where the local laws do not permit growing cannabis, cultivators ma y choose to grow in forests or rugged and rural areas where the local population are not likely to find the crop. Another technique is to grow cannabis in a cro p that is larger and obscures the plants, such as maize. This is reported by the United States government to be common in the midwestern states.[citation needed ] Bamboo and elderberry are also used as camouflage companion plants.[citation n eeded] Some government agencies, like the Drug Enforcement Agency, have claimed that in state and national parks, people have been injured by marijuana farmers protect ing their crops growing cannabis in US national parks and forests, through booby traps and the like, although no arrests or convictions have been made.[citation needed] [edit] Detection Often, simple camouflage techniques can avert detection, such as mixing cannabis plants with other bushy, leafy species. Plants started outdoors late in the sea son do not grow as tall, attracting less attention when placed next to plants of similar or taller stature. A common technique used by many outdoor growers is to dig a hole and put a potte d plant in it. This can reduce a plant's height by at least a foot, reducing vis ibility to neighbours, visitors and guests. Also, some growers top the plant whe n it is only 12 inches (30 cm) high, and grow the 2 tops horizontally along a tr ellis. When using this technique, it is unlikely the plant will grow to be over 3 feet (1 m) tall. Law enforcement agencies often monitor certain wider areas, particularly areas o f countryside with a significant history of outdoor cannabis cultivation. In hel icopters, they use infrared cameras and other equipment that can detect cannabis by measuring the heat and reflective signature of the vegetation below. Cannabi s has higher reflectivity at certain wavelengths than other rural crops, such as corn. Law enforcement agencies have found that the use of this technology has b ecome necessary in their detection efforts because many growers hide cannabis am ong other plants, making detection with the naked eye difficult even from the ai r. These techniques are effective and difficult to defeat because a plant's refl

ective signature is difficult to change or mask. It has been said[who?] that if the cannabis plant is planted by a pine or cedar tree the heat from the tree wil l overlap the cannabis plant heat making it harder to detect from helicopters.[c itation needed] [edit] Indoor Cannabis Cultivation Indoor Cannabis cultivation. Cultivating Cannabis indoors traditionally has to do with growing the plants in a soil-like medium and adding fertilizer when the plants are given water. Cultiv ating marijuana indoors is more complicated and expensive than growing outdoors, but it allows the cultivator complete control over the growing environment. Can nabis grown indoors can be just as potent as its outdoor counterpart if tended t o properly. Small buildings for cultivation are often known as grow-ops. Cultivating plants indoors can also be done through the use of hydroponics; howe ver, this method is somewhat less common.[17][18] In order to grow plants indoors, a growing medium (e.g. soil or growing substrat e), water, nutrients, light and air need to be supplied to the plant. [edit] Supply of light To determine the appropriate lighting (and the best lamp to use), the specific n eeds of the plant must be considered, as well as the room size and ventilation. To arrange optimal lighting, the lighting present in the plant's natural environ ment needs to be imitated.[19] For example vegetables grow best in full sunlight , which means in practice that as much light as possible must be supplied to gro w cannabis indoors (high intensity discharge (HID) lights such as high pressure sodium (HPS)and metal halide (MH) are preferred. Fluorescent lamps can also be u sed). Incandescence and mercury vapor lighting are not used in cannabis cultivat ion. In addition, plants also require both dark and light ("photo"-) periods. As such , lights need to be timed to switch them on and off at set intervals. The optimu m photo/dark-periods is specific depending on each plant (some prefer long days and short nights and others preferring the opposite, or something in between). Most plants will grow under most light spectra, yet always prefer a full spectru m light. A test done by Ed Rosenthal[citation needed] found that when a room was set up using both high pressure sodium (HPS) and metal halide (MH) lamps the pl ants in between the two lights did better than those under MH alone but not as w ell as those under HPS. However, certain plants (as cannabis) can be grown succe ssfully under both types of light. MH is used for vegetative phase of growth, as it encourages short inter nodes (distance between sets of leaves), and inhibits cell elongation, creating a shorter, stockier plant. Metal halide lamps produce more ultraviolet radiation than high pressure sodium lamps, which may play a ro le in increasing the flowering (and for certain plants as cannabis the amount of working substances as THC) produced by the plant. High pressure sodium lamps tr igger a greater flowering response in the plant and are thus used for the second (or reproductive) phase of the growth, or they are used by those people who onl y wish to purchase 1 single lamp.[20] If high pressure sodium lamps are used for the vegetative phase, plants will usually grow slightly more quickly, but will also have longer inter nodes, and may be taller.[21] Recent advancements in LED technology have allowed for diodes that emit enough e nergy for cannabis cultivation. In 1996, Graham Reinders, author of the celebrated book How to Super Charge your Garden wrote, referring to a 1000watt High Pressure Sodium light, “It has an en

ormous lumen output, but not a very good PAR output because most of its light is at the wrong frequency for plants. The bulb has most of the light spectrum in t he “orange” range, with almost no ‘blue’ and very little ‘red.’ For this reason, it is poor in the 430-460 nm, and poor in the 680 - 700 nm. Luckily, the light is so powerful that the spill -over at these frequencies is still sufficient to do a good job.” Thirteen years later, innovative people have taken this principa l shortcoming of the HPS and turned it into an advantage for LEDs. LED lights al low one to focus intensity in the high PAR absorption range of the light spectru m. New models of LED grow lights incorporate multiple types of chips that cover the whole range of red light, blue light, and now full spectrum light. One major short coming of LED’s in the past has been a lack of intensity. Higher wattage chips are required to produce enough luminous efficiency to produce lar ger, denser yields. As with using a 400w HPS vs. a 1000w HPS, intensity has ever ything to do with yield. The same applies to LEDs however, it is not as simple a s measuring watts because better quality chips can produce more light with less watts than cheap chips running at lower watts. LED grow lights are still considered an experimental technology in cannabis cult ivation. The market remains flooded with cheap quality LED lights that do not pr oduce yields comparable to what growers are accustomed to. Many companies are us ing single watt LED chips, which have notoriously produced low yields and wispy results. Growers should look for lights with 6 watt chips. When considering purc hasing LED grow lights, one should carefully examine both the spectrum and the i ntensity of the light. The advantages of LEDs, low heat output, long life span, and simpler environment al control, coupled with the ever increasing quality of the technology ensure th at they are here to stay and potentially to mark a significant transformation in the cultivation of cannabis. LED panel light source used in an experiment on plant growth by NASA. Pictured p lant is a potato plant. According to the inverse square law, the intensity of light radiating from a poi nt source (in this case a bulb) is inversely proportional to the square of the d istance from the source. So if an object is twice as far away, it receives only 1/4 the light. This is a serious hurdle for indoor marijuana growers, and many t echniques are employed to use light as efficiently as possible. Reflectors are often used in the lamps to maximize light efficiency. Plants or l ights are moved as close together as possible so that they receive equal lightin g and that all light coming from the lamps wind up on the plants (rather than pa rtly besides it). Often, the distance between lamp and plant is in the range of 0.6 m (2 ft) with incandescent lamps, to 10 cm (4 in) with other lamps, such as compact, large and high-output fluorescent lamps. Some marijuana cultivators cov er the walls of their grow-room with some type of reflective material (often Myl ar), or alternatively, white paint to maximize efficiency. One commonly used covering is 6 millimeter (150 µm) PVC plastic sheeting that is white on one side and black on the other. The plastic is installed with the whi te side facing in to the room to reflect light, and the black facing the wall, t o reduce fungus and mold growth. Another common covering is flat white paint, wi th a high titanium dioxide content to maximize reflectivity. Mylar sheeting from a grow store is very effective when it lines grow room walls, along with Astrof oil (which also reflects heat), and Foylon (a foil-laminated, reinforced fabric) . [edit] Control of the atmosphere When growing indoors, the cultivator should maintain as close to an ideal atmosp here inside the grow-room as possible. The air temperature should be maintained

within a specific range, typically with deviations no larger than 10 °C. with a cooler night and warmer day. Adequate levels of CO2 must be maintained in order for the plants to grow most efficiently. It is also important to promote vigorou s air circulation within the grow room, which is usually accomplished by mountin g an extraction fan and one or more oscillating fans. Assuming adequate light and nutrients are available to plants, the limiting fact or in plant growth is the level of carbon dioxide (CO2). Plants grown with suppl emental carbon dioxide will grow more quickly, have larger stomata, and can util ize more light. Ways of increasing carbon dioxide levels in the grow-room includ e: bottled carbon dioxide, carbon dioxide generators, a milk jug and yeast solut ion (in which yeast grows in a container thereby emitting CO2), a baking soda an d vinegar mixture in a container, or dry ice.[22] Certain plants (e.g. most strains of cannabis) emit a distinctive odor during th eir reproductive phase. This presents difficulties to those who are cultivating in places where it is illegal. The most common way of eliminating odor is by pul ling odorous air through a carbon filter. Many cultivators simply attach a large carbon filter to their air extraction system, thereby filtering any smell befor e the air is expelled from the grow-room. Another way of eliminating odor is by installing an ozone generator in the extraction ducting. The air is forced past the ozone generator by the extraction fan, and the odorous air is neutralized as it mixes with the ozone; however the cultivator must ensure that the air is tho roughly mixed before it is expelled outside, lest some odor escape. Care must be taken to prevent excessive ozone concentrations in the garden itself, or where it might be inhaled by the grower or his/her family. Ozone itself has a distinct ive smell and is harmful to living things, although the molecule breaks down qui ckly (20 minutes to an hour) in atmospheric conditions. [edit] Popularity Indoor cannabis plant during flowering Indoor growing has become increasingly common over the past decade, in part due to increased availability of equipment, seeds and instructions on how to cultiva te. So-called grow-ops (growing operations, often located in grow houses) are se en by many marijuana enthusiasts as a much cheaper way in which to gain a steady , higher-quality supply of cannabis. On a larger scale they have proven a viable commercial venture, with some law enforcement agencies finding grow-ops large e nough to yield several kilograms of marijuana. More expansive grow-ops, however, are generally more susceptible to detection than smaller operations. Since individual grow light power generally ranges from 250 watts to in excess o f 1000 watts and remains lit for a long time each day, differences in utility bi ll costs are a significant security issue. It is not uncommon for power companie s to work with law enforcement if they witness significant increases in power us age relative to a household s previous electricity costs. Employing energy savin g methods is a common way to alleviate this, for instance; switching off light b ulbs when leaving rooms, purchasing energy efficient appliances, using TVs or co mputers less, buying lower power light bulbs and so forth. Some plants (e.g. cultivators of Cannabis sativa subsp. indica), can give off st rong odors as they grow, resulting in detection of illegal growing operations. G rowers frequently use carbon scrubbers in conjunction with ventilation in order to control odors. This typically involves forcing air from the grow room through a device containing activated carbon, before being vented outdoors. Others use an ozone generator. Ozone reacts with odor molecules in the air, permanently eli minating them. However, ozone can build up to levels that may be hazardous both for the grower and the plant. As a last resort, strong air fresheners are used t o control smells as well as keeping windows firmly shut. This is a risky method, as the smell of air fresheners may often arouse suspicion by police officers. C hecking outside to see if any smells are emanating from indoors is often a neces

sary precaution, as many growers become acclimated to the smell, and fail to rea lize just how pervasive the odor may be. Many store plants in more isolated area s such as a basement or attic to prevent smell detection. Another less common so lution is to simply grow a strain which possesses a weaker odor. Storing plants and lights away from windows and areas which may be seen by visit ors is also a common practice, as is keeping the entire grow op in an attic or b asement. Some growers, finding this impractical, may cover their windows with li ght-resistant materials. This can solve the problem of escaping bright light but may arouse suspicion amongst neighbors and local residents. Many cultivators face detection by fire. Fires normally originate from faulty el ectrical equipment or wiring. Shoddy fixtures and sockets, improperly grounded e quipment, and faulty circuit breakers are some of the most prevalent causes. Due to the large amount of electricity needed for large-scale cultivation, old or d amaged wiring is prone to melt and short. Some commercial growers resort to powe r theft in order to hide electricity usage and many do not take precautions to e nsure that their connections are safe. Many growers adapt light cycles so that t he lights are on when they are home and off when they are away. Another fire hazard is plants making contact with hot HID bulbs. Growers using f luorescent bulbs with reasonable air circulation do not have this problem. Word of mouth can of course be as much a threat to growers as any of the above i ssues. Often, a few sentences of conversation overheard can result in a tip-off and thus speedy detection. It is for this reason that many growers are reticent to talk about their cultivation. [edit] Housing damage For houses used as grow-ops, the interiors may have received significant structu ral, electrical and heating system modifications not in accordance applicable bu ilding, natural gas and electrical codes, such as overloaded existing electrical system or a bypass circuit to avoid paying for the electricity required to powe r the high intensity light bulbs and fans; disconnected furnace venting; or hole s in floors and walls for increased airflow. These changes are made to replicate warm, humid climates in which hybrid plants flourish to produce high potency ma rijuana. Such modifications results in considerable structural damage, as well a s cultivation over a period of time which leads to moisture and toxic mold.[23][ 24] Grow-op homes appear to be maintained in their normal fashion on the outside. No netheless, there are plenty of tell-tale signs, such as occupants often avoid th eir neighbors, a "beware of the dog" sign, and melted snow in the winter (due to the higher-than normal heating to cultivate these plants).[25] One of the largest such examples was masterminded by a Markham, Ontario real est ate agent, John Trac, who turned 54 rented houses into grow-ops. He has since be en convicted and imprisoned, however his second-in-command, Jennifer Trac, is st ill at large. Hydro companies estimated the value of the electricity stolen and insisted that homeowners pay before hooking them up again.[26][27] Contractor and TV personality Mike Holmes has said that while former grow-ops ca n be had at bargain-basement prices, being sold off by banks or homeowners to re coup their loses, he warns that the repairs and remediation can be around $10000 0 CAD which may outweigh any initial buyer savings. Holmes noted in one of his p ast jobs on Holmes on Homes, he and his crew gutted the entire house after disco vering it was a grow-op.[28][29] Usually, after the police bust a grow-op house, they are supposed to contact the municipality to ensure that the place is cleaned up before it goes to market, w

hile real estate agents and sellers are required by law to disclose that the hom e was a past grow-op. However, on one episode of CBC s Marketplace, Holmes and E rica Johnson found out that the agents and sellers were frequently dishonest. Fu rthermore, home inspectors routinely failed to detect tell-tale signs that the h ouse was a former grow-op. During a test caught on hidden camera, the inspectors passed off the former grow-op home as having minor problems.[28][29] [edit] Harvesting, drying and curing Close-up of a female marijuana bud in flowering stage. White trichomes can be se en coating the surface, which will darken as flowering progresses. A typical indicator that a plant is ready to be harvested is when 2/3 of the pis tils have turned from white to reddish brown or other color. In general, harvest ing consists of drying and curing. Curing is essential for the even distribution of moisture in the buds. A popular alternate method is the following: 1. 2. 3. 4. 5. 6.

Dry: Buds left in well ventilated dark place for Cure: Buds stored in sealed bag and left in dark Dry: Buds left in well ventilated dark place for Cure: Buds stored in sealed bag and left in dark Dry: Buds left in well ventilated dark place for Steps continued likewise as necessary

24 hours place for 8 hours 16 hours place for 6 hours 12 hours

In 3–4 days buds are ready for consumption.[30] Cannabis buds are typically harvested when fully ripe. Generally, ripeness is de fined as when the white pistils start to turn dark yellow, orange, light to mid red, etc. and the trichomes, "crystals", barely begin to turn milky from clear. [31] These trichomes can range from completely clear (generally deemed underdeve loped), to amberish-red. Ideally, professionals will use a decent power magnifyi ng glass, a brix meter (to measure "sugar" content), and a microscope. The poten tial seed pods swell with resins usually reserved for seed production, thus impr oving the quality of the buds (called colitas, Spanish for "little tails"), whic h will swell to form full "colas" (Spanish for "tails"). If harvested early on w ith only a few of the pistils turned color, the buds will have a more pure THC c ontent and less of the cannabinoids CBD and CBN. The latter cannabinoids are non -psychoactive; they contribute to the bouquet of the marijuana and modulate the overall nature of the high anywhere from purely psychedelic to purely sedative. Contrary to sinsemilla (bud production focused cultivation), seeds are harvested when fully developed and often after the accompanying buds have begun to deteri orate. In contrast, hemp grown for fiber is harvested before flowering, and cann abis grown for cloning is not flowered at all. [edit] Drying The plants are dried at room temperature in a dark space. This process can take from a few days to two weeks, depending on the size and density of the buds and the relative humidity of the air. A stable temperature preserves cannabinoids we ll. Some believe flowers are hung by their stalks, allowing the internal fluids of the plant to remain in the flowers. Others believe the cut stem is simply a h andy non-sticky place from which to hang the plant. Roots are removed. When the stems in the middle of the largest buds can be snapped easily, the plant is dry enough to be cured. Drying is done in a dark place, as THC resins will deteriora te if exposed to light and the degradation product CBN will be formed, thus sign ificantly altering the cannabinoid profile of the dried flowers. [edit] Curing The curing process continues breaking down sugars and helps develop taste and sm oothness of smoke. Usually, the dried product is packed (not compressed) into gl ass canning jars which are airtight. Initially the product is checked periodical ly (every few hours) to make sure it was properly dried and has not re-moistened

itself. After several days, when the product is dried to satisfaction, the jars are sealed off and opened just once a week. Curing is highly varied—the minimum is usually two weeks. Some growers even cure as long as six months, while other s do not cure at all. As with tobacco, curing can make the cannabis more pleasan t to smoke. For the same reasons as when drying, curing jars are stored in a coo l, dark place. A recent method of curing is called water curing. This method is quicker and can improve a lower quality product. The freshly cut buds are submersed in water fo r a period of 7 straight days, changing the water daily. The buds are then dried and are ready to use. Nutrients can be added to the plants up until they are ha rvested. When water curing, the water will flush out harmful chemicals (such as the ones used to feed the plants) as well as proteins, sugars, pigments, chlorop hyll and some resins. This will also increase the THC to weight ratio.[32] Many believe the finished product is not as attractive as using a standard dry and cu re Tincture. Ethanol is used to extract cannabinoids from the marijuana plant (THC is soluble in alcohol). The extraction process takes longer, but results in an e dible product. Marijuana stems, leaves and buds can all be used. The resulting m ixture can be eaten straight, mixed with food or even smoked. Many smokers prefe r to dip cigarettes in the mixture, which allows them to smoke in public without detection. Contact with direct flame causes this liquid to lose its THC content (THC vaporizes at 180°C). Smokers usually heat the liquid and inhale the vapors through a straw. [edit] Hash Main article: Hashish Hashish can be expensive but like everything else in cannabis cultivation, it ca n be an investment that pays for itself. After a harvest, there are typically ma ny green leaves- particularly large shade leaves- which themselves cannot be smo ked, but have collected over time many fallen trichomes. Rather than letting the m go to waste, these are soaked in a bucket of cold water. The liquid is then pa ssed through a succession of bags with decreasing screen sizes which capture the trichromes, which are then pressed into shape and let dry. The result is called bubble hash, due to the bubbling which occurs when it is heated for smoking. Th is bubbling is due to its purity, as adulterants tend to cause hash not to bubbl e.[33] [edit] Hash oil Main article: Hash oil Allowing the ethanol in a tincture to evaporate makes hash oil. However, ethanol , should never be evaporated with direct heat or near an open flame. The resulta nt hash oil is often very strong in terms of THC content (depending on parent ma terial), and can be then smoked. Delta 9 THC is most strongly soluble in petrole um ether and less so in ethanol. Adding petroleum ether to tincture will extract D9 THC, and leave water soluble chemicals in the ethanol (certain cannabinoids, proteins, chlorophyll, etc.). Hash oil purified this way can exceed 90% D9 THC. [edit] Pests Outdoor growers are likely to confront issues regarding pests. In any case (indo or or outdoor), experienced growers recommend caution when using chemical pestic ides, for they may have toxic effects on the environment, the plants themselves and in turn cannabis consumers. As a general rule, experts mandate the deploymen t of pesticides clearly marked as "safe to use on food crops". Substances proven to induce little or no harm include: * Pyrethrins: Organic and very effective, although sometimes hard to find. O ften expensive due to high production cost. * Azadirachtin: Meets most criteria to be classified as natural insecticide.

Biodegradable, non-toxic to mammals. Usually cheaper and easier to find than py rethrins. Indoor growers also have problems with pests, usually caused by the grower or a pet bringing them in from the outdoors. If caught too late, eradication of many destructive insect species indoors may be impossible until all infected plants a re removed from the space and sterilization methods employed. [edit] Advanced cultivation methods The legal status of cannabis has led growers to implement novel cultivation meth ods for indoor growing which involves the use of lamps, in order to avoid aerial surveillance of outdoor plots.[34] These methods include: 1. using a water or air-based growth medium (known as hydroponics and aeropon ics respectively) 2. the use of homemade, organic composted fertilizers 3. training and trellising techniques such as Screen of Green (also known as SCROG), Sea of Green (also known as SOG) "Super cropping" and LST super cropping ; and entire systems and methods such as the NIMBY no-dump method, Hempy Bucket, and the Krusty Freedom Bucket methods. Research into the production of cannabis for the drug Marinol and other more profitable and marketable forms of cannabis based medicines has further pushed the envelope of cannabis cultivation in all forms of laboratory, both public and private. The emphasis on advanced cultivation techniques, as well as the availability of hybrid strains (with names like Northern Lights, Master Kush, NYC Diesel), is be lieved to be a factor in the increase in the overall quality and variety of comm ercially-available cannabis over the past few decades. The internet in particula r has brought together widely diverse genetics from around the world through tra ding and purchasing. However, well-grown heirloom strains (e.g. island sweet sku nk, fruity Thai etc.) are used to produce 1 gram per watt harvest. [edit] SOG In contrast to the "Screen of Green" method, Sea of Green (or SOG) growing depen ds on the high density of plants (as high as 60 per square meter) to create unif ormity in the crop. In this technique, which is often grown in hydroponic media, only the colas of the plants are harvested. Containers are used to enforce the geometric distribution of flowers and plant material, as well as their exposure to lighting and atmosphere. Sea of green is popular with commercial cultivators, as it minimizes the amount of time a plant spends in vegetative stage, and allo ws very efficient light distribution, keeping the plants much closer to the ligh ts than when grown to full size. However, the individual plants grown with this method typically give smaller yields than those grown with other methods.[citati on needed] [edit] SCROG SCROG, short for SCReen Of Green, is an advanced training technique for Cultivat ing Cannabis, mainly indoors. Closely resembles SOG (or Sea Of Green) with the d ifference being that SCROG uses extensive training to produce the same field of bud effect with only one plant. Medical growers may find this a helpful techniqu e to maximize harvest if they are only allowed a certain number of plants. A scr een such as chicken wire is hung over plants so that the tips of branches are ke pt at the same level. This allows even light distribution to all of the nodes/bu d sites. Once the flowering stage is initiated, the flower tips will reach throu gh the wire and all be at relatively equal distances from the light source. Light Depreciation: The Inverse Square Law [35] states, as the distance from the light source is doubled, the light intensity is quartered. Cannabis growers rea lize this and want to get the maximum use for their lights. With an untrained pl ant the lower branches of their plants don t produce as well as the upper branch

es, being too far from the light. The SCROG method reduces this problem by putti ng basically the whole plant on one vertical plane, allowing all bud sites to re ceive nearly maximum light. This is beneficial because it produces more by getti ng light where the plant needs it.Vegetative State: The plant should remain in t he vegetative state until 70 to 80 percent of the net is full[36] As a branch re aches three to four inches above the wire it is pulled back under the wire and s o trained to grow vertically until flowering. Due to the amount of plant require d to fill the net, the vegetative period may require longer than normal to be re ady for flowering. Timing: Timing is vital to the success of a SCROG grow. If the net is not full a t harvest, valuable space has been wasted. If the net is too full then the buds will be too crowded to develop properly. Knowing how a plant grows can help to v isualize when to flower for maximum effect. [edit] Hydroponics Main article: Hydroponics An example for a small hydroponic system for cannabis cultivation Hydroponic cultivation generally occurs indoors, although there is no practical obstacle to growing outdoors. In general, it consists of a non-soil medium which is exposed to a nutrient and water flow. There are many types of hydroponic systems. If the nutrient solution floods the loose growing medium and recedes for aeration, this is an ebb and flow or flood and drain system. Systems that gradually drip solution onto the medium are drip systems. Systems that intermittently spray roots floating in air are called aero ponic systems. If aerated water runs down a channel lined with a film of rooting medium, this is a nutrient film technique system. A series of tubes intermitten tly running high flow nutrient solution into the tops of growing containers use a top feed system. Hydroponic systems greatly increase aeration of plant roots, and increase contro l of nutrient uptake. Hydroponic systems are decidedly more difficult to operate for the amateur or hobby grower, as over-fertilization is common, because there is no soil to act as a nutrient buffer. For this reason, many growers now use c oconut fiber as a soil-less medium due to its high drainage and buffering capabi lities, making it almost impossible to over-fertilize. Additionally, if a hydrop onic system fails, the crop has a high probability of dying as the roots rapidly dry out (this is especially true of aeroponic systems). There is now a new breed of hydroponic configurations such as the Omega Garden, the B-Pod and the EcoSystem Vertical Growing System that use circular designs to maximize efficiency. This consists of plants being placed or, in the case of th e Omega Garden, revolving around a central light which makes maximum use of the light output. [edit] Genetics [edit] Selection of mother plants An important factor in cannabis cultivation is selecting the best genetics for o ne s crop. This is frequently done by selecting one or more known strains, or st rains with preferred genetics (in the case of marijuana, one might use seeds fro m a batch that was particularly enjoyed), and then growing a number of the seeds to find out which exhibit the characteristics most desirable to the cultivator. These genetics should typically yield at least 1 gram per watt. Plant characteristics which are generally selected for include: * Overall yield * Time to fruition * Resistance to pests

* * * * * *

Geometric traits (uniformity, compactness, flower density, etc.) Color Flavor and/or aroma Appeal to end buyer (known as "bag appeal") Psychoactive qualities Trichome density and type (stalked or sessile)

When a cultivator has decided which plant or plants exhibit the most desirable t raits, a cutting is taken and grown to maturity but never allowed to flower. Thi s plant is referred to as a mother, and can be kept for years, producing thousan ds of clones genetically identical to the mother.[37] [edit] Feminized seeds It is possible to use a combination of cloning and "shocking" plants to get them to produce feminized seeds.[38] A clone will retain the same sex throughout its life, so if a female plant is cloned, its clones will also be female, precludin g reproduction. Some claim (particularly vendors of feminized seeds produced with certain method s) that while environmental stresses have been used to create pollen bearing mal e flowers on female plants- known as hermaphroditing or hermying , this metho d is not preferred when creating feminized seeds; due to those plants most likel y to revert to seed making being the ones which hermie sooner; hence passing on the genetic trait of instability of gender - desirable in the wild but not in cu ltivation. Spraying selected leaves, branches and in cases where large amount of seed desir ed whole plants with colloidal silver solution has become a preferred method sin ce the colloidal silver suppresses ethylene production in bud sites, stimulating male characteristics. Gibberellic acid has been used frequently; but is harder to find than colloidal silver, which involves nothing more than a small wall d.c . power supply and two pieces of solid silver jeweler s wire, or 99.999% silver coin. A method used by organic growers and promulgated by the famous Cannabis br eeder Soma, is called Rodelization , or letting unpollenated female plants live several weeks longer than the normal harvest time. In such plants a hermaphrodi tic trait will self express in effort to continue the genetic line; the fact thi s method utilizes auto hermaphroditic traits which could contribute to instabili ty in a plant s genetics is offset by grower observations that the tendency to a uto-switch sex is not great in plants grown from seeds made this way, and the fa ct that it occurs naturally without effort on the part of the cultivator. However, other cultivators claim that the genes responsible for hermaphroditism are present and may be activated under stress from any of the above methods and that once activated can be passed to seeds regardless of how it was activated. T raditional theories of inheritance would not have allowed for the passing of gen etic alterations an adult has acquired after birth (called Epigenetics) but ther e is evidence that when a gene is activated in a mother after her birth that exp ression can be passed on to her offspring.[39] [edit] Hybrid vigor When crossing two strains of cannabis (or two of any plant), the resultant hybri d may possess what is called hybrid vigor. In general, this produces a plant whi ch is healthier, stronger, or quicker growing than its predecessors. Sometimes, in the case of a plant which has been brought back from fruiting (fruition, as m entioned above), it may be beneficial to cross it back with another (close) rela tive, in the hopes that it will become invigorated.[40] Caution should be exercised, as one does not always attain a beneficial cross wi th hybridizing. [edit] Vegetative propagation (cloning)

Like most plants, cannabis has the potential for vegetative propagation, with th e most common and simple method being cutting. Cutting is characterized as a clo ning method, since the derived plants have identical DNA to the "mother plants". [41] Under appropriate environmental conditions, a cut part of the cannabis plant, ty pically from the main stem or a lateral branch, has the ability to produce roots and develop into a whole new plant (the clone), genetically identical to the mo ther. In cannabis, the production of roots may take anywhere from 5 to 21 days. The main steps of cannabis cutting are as follows: 1. Part of the main stem or lateral branch up to 20 cm long is dissected in a non-vertical manner. The bottom 2/3 of leaves are removed. 2. The cutting is brought to contact with rooting hormone according to instru ctions in order to promote root growth and inhibit fungal infection. 3. After initial root development, the cutting is placed in an appropriate me dium such as common soil, perlite, vermiculite, peat moss, sand, rock wool, or o asis foam. The medium is kept moist and high humidity is maintained in the surro unding air. Elevated humidity levels slow the transpiration rate (water loss fro m leaves) and prevent the cutting from drying out. During this phase, the temper ature is kept relatively low (25 C) and direct light is avoided so that the cutt ing focuses in root production rather than photosynthesis. Considerations * Some growers recommend that the mother is allowed to become mildly nitroge n deficient before the cutting, as this can speed up rooting. * Temporary removal of the high-humidity environment (e.g. twice a day) and fanning will promote air circulation and prevent the formation of mold. * Successful cuttings retain green color during rooting, however yellow leaf tips are expected. Browning indicates too much sunlight, too little humidity, c utting rotting in sitting water, or unsanitary cloning conditions. [edit] Humid environment Many growers use relatively cheap (around $7) humidity domes. Others improvise d omes with simple plastic covers secured with rubber bands. In recent years, comp anies specialized in hydroponics have introduced automated devices (like EZClone r) that simulate ideal conditions for the cuttings, reduce the overall rooting p eriod to two weeks and require little or no intervention. Some advanced growers claim that these devices achieve absolute success rates, however their high mark et price (over $300 USD) is considered prohibitive for common growers.