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Gemini 10

Gemini 10 (officially Gemini X) was a 1966 crewed spaceflight in NASA's Gemini program. It was the 8th crewed Gemini flight, the 16th crewed American flight, and the 24th spaceflight of all time (includes X-15 flights over 100 km). During the mission, flown by future STS-1 Commander John Young and future Apollo 11 Command Module Pilot Michael Collins, Collins became the first person to perform two extravehicular activities.

Support crew

 * Edwin E. "Buzz" Aldrin (Houston CAPCOM)
 * L. Gordon Cooper Jr. (Cape and Houston CAPCOM)

Jim Lovell and Buzz Aldrin had originally been named the backup crew, but after Charles Bassett and Elliot See died in a T-38 crash, they were moved to the backup crew for Gemini 9 and Alan Bean and Clifton Williams were moved to the Gemini 10 flight.

Mission parameters

 * Mass: 3,762.6 kg
 * Perigee: 159.9 km
 * Apogee: 268.9 km
 * Inclination: 28.87°
 * Period: 88.79 min

Docking

 * Docked: July 19, 1966 - 04:15:00 UTC
 * Undocked: July 20, 1966 - 19:00:00 UTC

Space walk

 * Collins - EVA 1 (stand up)
 * Start: July 19, 1966, 21:44:00 UTC
 * End: July 19, 1966, 22:33:00 UTC
 * Duration: 0 hours, 49 minutes
 * Collins - EVA 2
 * Start: July 20, 1966, 23:01:00 UTC
 * End: July 20, 1966, 23:40:00 UTC
 * Duration: 0 hours, 39 minutes

Objectives
Gemini 10 was designed to achieve rendezvous and docking with an Agena Target Vehicle (ATV), and EVA. It was also planned to dock with the ATV from the Gemini 8 mission. This Agena's battery power had failed months earlier, and an approach and docking would demonstrate the ability to rendezvous with a passive object. It would also be the first mission to fire the Agena's own rocket, allowing them to reach higher orbits.

Gemini 10 established that radiation at high altitude was not a problem. After docking with their Agena booster in low orbit, Young and Collins used it to climb temporarily to 763.8 km. After leaving the first Agena, they then rendezvoused with the derelict Agena left over from the aborted Gemini 8 flight—thus executing the program's first double rendezvous. With no electricity on board the second Agena, the rendezvous was accomplished with eyes only—no radar. After the rendezvous, Collins spacewalked over to the dormant Agena at the end of a 50 ft tether, making him the first person to meet another spacecraft in orbit. Collins then retrieved a cosmic dust-collecting panel from the side of the Agena. As he was concentrating on keeping his tether clear of the Gemini and Agena, Collins' Hasselblad camera worked itself free and drifted away, so he was unable to take photographs during the spacewalk.

Flight
The Agena launched perfectly for the second time, after problems had occurred with the targets for Gemini 6 and 9. Gemini 10 followed 100 minutes later and entered a 159.9 by orbit. They were 1800 km behind the Agena. Two anomalous events occurred during the launch. At liftoff, a propellant fill umbilical became snared with its release lanyard. It ripped out of the LC-19 service tower and remained attached to the second stage during ascent. Tracking camera footage also showed that the first stage oxidizer tank dome ruptured after staging and released a cloud of nitrogen tetroxide. The telemetry package on the first stage had been disabled at staging, so visual evidence was the only data available. Film review of the Titan II ICBM launches found at least seven other instances of post-staging tank ruptures, most likely caused by flying debris, second stage engine exhaust, or structural bending. NASA finally decided that this phenomenon did not pose any safety risk to the astronauts and took no corrective action.

First rendezvous
Collins was unable to use the sextant for navigation as it did not seem to work as expected. At first he mistook airglow as the real horizon when trying to make some fixes on stars. When the image didn't seem right he tried another instrument, but this was not practical to use as it had a very small field of view.

They had a backup in the form of the computers on the ground. They made their first burn to put them into a 265 by orbit. However Young didn't realize that during the next burn, he had the spacecraft turned slightly, which meant that they introduced an out-of-plane error. This meant two extra burns were necessary, and by the time they had docked with the Agena, 60% of their fuel had been consumed. It was decided to keep the Gemini docked to the Agena as long as possible, as this would mean that they could use the fuel on board the Agena for attitude control.

The first burn of the Agena engine lasted 80 seconds and put them in a 294 by orbit. This was the highest a person had ever been, although the record was soon surpassed by Gemini 11, which went to over 1000 km. This burn was quite a ride for the crew. Because the Gemini and Agena docked nose-to-nose, the forces experienced were "eyeballs out" as opposed to "eyeballs in" for a launch from Earth. The crew took a couple of pictures when they reached apogee but were more interested in what was going on in the spacecraft — checking the systems and watching the radiation dosage meter.

After this they had their sleep period which lasted for eight hours and then they were ready for another busy day. The crew's first order of business was to make a second burn with the Agena engine to put them into the same orbit as the Gemini 8 Agena. This was at 20:58 UTC on July 19 and lasted 78 seconds and took 105 m/s off their speed, putting them into a 294 by orbit. They made one more burn of the Agena to circularize their orbit to 377.6 km.

EVA 1
The first of two EVAs on Gemini 10 was a standup EVA, where Collins would stand in the open hatch and take photographs of stars as part of experiment S-13. They used a 70 mm general purpose camera to image the southern Milky Way in ultraviolet. After orbital sunrise Collins photographed a color plate on the side of the spacecraft (MSC-8) to see whether film reproduced colors accurately in space. He reentered the spacecraft six minutes early when both astronauts found that their eyes were irritated, which was caused by a minor leak of lithium hydroxide in the astronauts' oxygen supply. After repressurizing the cabin, they ran the oxygen at high rates and flushed the environment system.

After the exercise of the EVA Young and Collins slept in their second 'night' in space. The next 'morning' they started preparing for the second rendezvous and another EVA.

Second rendezvous
After undocking from their Agena, the crew thought they sighted the Gemini 8 Agena. It however turned out to be their own Agena 5.5 km away, while their target was 176 km away. It was not until just over 30 km away that they saw it as a faint star. After a few more correction burns, they were station-keeping 10 ft away from the Gemini 8 Agena. They found the Agena to be very stable and in good condition.

EVA 2
At 48 hours and 41 minutes into the mission, the second EVA began. Collins' first task was to retrieve a Micrometeorite Collector (S-12) from the side of the spacecraft. This he accomplished with some difficulty (similar to that encountered by Eugene Cernan on Gemini 9A). The collector floated out of the cabin at some time during the EVA, and was lost.

Collins next traveled over to the Agena and tried to grab onto the docking cone but found this impossible as it was smooth and had no grip. He used a nitrogen-propelled Hand-Held Maneuvering Unit (HHMU) to move himself towards the Gemini and then back to the Agena. This time he was able to grab hold of some wire bundles and retrieved the Micrometeorite Collector (S-10) from the Agena. He decided against replacing it as a piece of shroud had come loose on the Agena which could have snared the umbilical, and returning to the Gemini was deemed the safest course of action.

The last tasks remaining on this EVA were to test out the HHMU, test orbital mechanics using a tether between the Gemini and Agena, and for Young in the spacecraft to translate over to a passive Collins. However, due to low propellant quantity remaining, combined with intermittent telemetry to monitor it, these fuel costly manoeuvres were abandoned and the EVA was finished after only 39 minutes. During this time, it took the crew eight minutes to close the hatch as they had some difficulty with the 50 ft umbilical. It was jettisoned along with the chestpack used by Collins an hour later when they opened the hatch for the third and final time.

Experiments
There were ten other experiments that the crew performed during the mission. Three were interested in radiation: MSC-3 was the Tri-Axis Magnetometer which measured levels in the South Atlantic Anomaly. There was also MSC-6, a beta spectrometer, which measured potential radiation doses for Apollo missions, and MSC-7, a bremsstrahlung spectrometer which detected radiation flux as a function of energy when the spacecraft passed through the South Atlantic Anomaly.

S-26 investigated the ion and electron wake of the spacecraft. This provided limited results due to the lack of fuel for attitude control, but found that electron and ion temperatures were higher than expected and it registered shock effects during docking and undocking.

The S-5 and S-6 experiments were performed, which were previously carried on Gemini 9A; these were Synoptic Terrain and Synoptic Weather photography respectively. There was also S-1 which was intended to image the Zodiacal light. All of these experiments were of little use as the film used was only half as sensitive as Gemini 9A and the dirty windows lowered the transmission of light by a factor of six.

The crew also tried to perform D-5, a navigation experiment. They were only able to track five stars, with six needed for accurate measurements. The last experiment, D-10, was to investigate an ion-sensing attitude control system. This experiment measured the attitude of the spacecraft from the flow of ions and electrons around the spacecraft in orbit. The results from this experiment showed the system to be accurate and responsive.

Re-entry

The last day of the mission was short and retrofire came at 70 hours and 10 minutes into the mission. They landed only 5.6 km away from the intended landing site and were recovered by USS Guadalcanal (LPH-7).

The Gemini 10 mission was supported by the following U.S. Department of Defense resources: 9,067 personnel, 78 aircraft and 13 ships.

Insignia
The patch is simple in design but highly symbolic. The main feature is a large X with a Gemini and Agena orbiting around it. The two stars have a variety of meanings: the two rendezvous attempts, Castor and Pollux in Gemini or the two crew members. This is one of the few crew patches without the crew's name. It is able to be displayed "upside down" but is correctly shown with the spacecraft to the right. It was designed by Young's first wife, Barbara.

Spacecraft location
For many years the spacecraft was the centerpiece of a space exhibition at Norsk Teknisk Museum, Oslo, Norway. It was returned on request in 2002.

The spacecraft is currently on display at the Cosmosphere in Hutchinson, Kansas.

title: Gemini 10


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Gardening

Gardening is the process of growing plants for their vegetables, fruits, flowers, herbs, and appearances within a designated space. Gardens fulfill a wide assortment of purposes, notably the production of aesthetically pleasing areas, medicines, cosmetics, dyes, foods, poisons, wildlife habitats, and saleable goods (see market gardening). People often partake in gardening for its therapeutic, health, educational, cultural, philosophical, environmental, and religious benefits. Gardening varies in scale from the 800 hectare Versailles gardens down to container gardens grown inside. Gardens take many forms, some only contain one type of plant while others involve a complex assortment of plants with no particular order.

Gardening can be difficult to differentiate from farming. They are most easily differentiated based on their primary objectives. Farming prioritizes saleable goods and may include livestock production whereas gardening often prioritizes aesthetics and leisure. As it pertains to food production, gardening generally happens on a much smaller scale with the intent of personal or community consumption. It is important to note that there are cultures which do not differentiate between farming and gardening. This is primarily because subsistence agriculture has been the main method of farming throughout its 12,000 year history and is virtually indistinguishable from gardening.

Prehistory
Plant domestication is seen as the birth of agriculture. However, it is arguably proceeded by a very long history of gardening wild plants. While the 12,000 year-old date is the commonly accepted timeline describing plant domestication, there is now evidence from the Ohalo II hunter-gatherer site showing earlier signs of disturbing the soil and cultivation of pre-domesticated crop species. This evidence pushes early stage plant domestication to 23,000 years ago which aligns with research done by Allaby (2022) showing slight selection pressure of desirable traits in Southwest Asian cereals (einkorn, emmer, barley). Despite not qualifying as plant domestication, there are many archaeological studies pushing the potential date of hominin selective ecosystem disturbance back up to 125,000 years ago. Much of these early recorded ecosystem disturbances were made through hominin use of fire, which dates back to 1.5 Mya (although at this time fire was not likely being wielded as a landscape-changing tool by hominids). This anthropogenic ecosystem disturbance may be the origins of gardening.

Every hunter-gatherer society has developed a niche of some sort, allowing them to thrive or even just survive amongst their environments. Many of these prehistoric hunter-gatherers had constructed a niche allowing for easier access to, or a higher amount of edible plant species. This shift from hunting and gathering to increasingly modifying the environment in a way which produces an abundance of edible plant species marks the beginning of gardening. One of the most documented hominin niches is the use of off-site fire. When done intentionally, this is often called forest gardening or fire stick farming in Australia. The modern study of fire ecology describes the many benefits off-site fires may have granted these early humans. Some of these agroecological practices have been well documented and studied during colonial contact. However, they are vastly under represented in research done on early hominin fire use. Based on current research, it is evident that these niches developed separately in different societies across different times and locations. Many of the Indigenous gardening methods were and still are often overlooked by colonizers due to the lack of resemblance to western gardens with well defined borders and non-naturalized plant species.

The Americas
There are long traditions of gardening within Indigenous societies spanning from the northernmost parts of Canada down to the southernmost tip of Chile and Argentina. The Arctic and Subarctic societies relied primarily on hunting and fishing due to the harsh climate although they have been known to collectively use at least 311 different plants as foods or medicines. The substantial knowledge and use of these plants along with the communal harvesting sites and emphasis on reciprocity between humans and plants indicates a basic level of gardening. Similarly, the Fuegian Indigenous groups in South America had developed seemingly comparable niches due to a similar tundra ecosystem. While there are very few studies on the Fuegians, Darwin mentioned wild edible plants such as fungi, kelp, and wild celery growing next to the various Fuegian shelters. Horticulture plays a relatively small role in these northern and southern tundra inhabitants compared with Indigenous societies in grassland and forest ecosystems. From the boreal forests of Canada to the temperate forests and grasslands of Chile and Argentina different communities have developed food production niches. These include the use of fire for ecosystem maintenance and resetting successional sequences, the sowing of wild annuals, the sowing of domesticated annuals (e.g. three sisters, New World crops), creating berry patches and orchards, manipulation of plants to encourage desired traits(e.g. increased nut, fruit, or root production), and landscape modification to encourage plant and animal growth (e.g. complex irrigation or terraces). These modified landscapes as recorded by early American philosophers such as Thoreau, and Emmerson were described as exhibiting pristine beauty. Indigenous gardens such as forest gardens therefore do not only serve as a producer of foods, medicines, or materials, but also pleasant aesthetics.

Many popular crops originate from pre-colonial Indigenous agricultural societies. Some of these include maize, quinoa, common bean, peanut, pumpkin, squash, pepper, tomato, cassava, potato, blueberry, cactus pear, cashew, papaya, pineapple, strawberry, cacao, sunflower, cotton, Pará rubber, and tobacco.

Ancient times
Forest gardening, a forest-based food production system, is the world's oldest form of gardening.

After the emergence of the first civilizations, wealthy individuals began to create gardens for aesthetic purposes. Ancient Egyptian tomb paintings from the New Kingdom (around 1500 BC) provide some of the earliest physical evidence of ornamental horticulture and landscape design; they depict lotus ponds surrounded by symmetrical rows of acacias and palms. A notable example of ancient ornamental gardens were the Hanging Gardens of Babylon—one of the Seven Wonders of the Ancient World —while ancient Rome had dozens of gardens.

Wealthy ancient Egyptians used gardens for providing shade. Egyptians associated trees and gardens with gods, believing that their deities were pleased by gardens. Gardens in ancient Egypt were often surrounded by walls with trees planted in rows. Among the most popular species planted were date palms, sycamores, fig trees, nut trees, and willows. These gardens were a sign of higher socioeconomic status. In addition, wealthy ancient Egyptians grew vineyards, as wine was a sign of the higher social classes. Roses, poppies, daisies and irises could all also be found in the gardens of the Egyptians.

Assyria was renowned for its beautiful gardens. These tended to be wide and large, some of them used for hunting game—rather like a game reserve today—and others as leisure gardens. Cypresses and palms were some of the most frequently planted types of trees.

Gardens were also available in Kush. In Musawwarat es-Sufra, the Great Enclosure dated to the 3rd century BC included splendid gardens.

Ancient Roman gardens were laid out with hedges and vines and contained a wide variety of flowers—acanthus, cornflowers, crocus, cyclamen, hyacinth, iris, ivy, lavender, lilies, myrtle, narcissus, poppy, rosemary and violets —as well as statues and sculptures. Flower beds were popular in the courtyards of rich Romans.

The Middle Ages

The Middle Ages represent a period of decline in gardens for aesthetic purposes. After the fall of Rome, gardening was done for the purpose of growing medicinal herbs and/or decorating church altars. Monasteries carried on a tradition of garden design and intense horticultural techniques during the medieval period in Europe. Generally, monastic garden types consisted of kitchen gardens, infirmary gardens, cemetery orchards, cloister garths and vineyards. Individual monasteries might also have had a "green court", a plot of grass and trees where horses could graze, as well as a cellarer's garden or private gardens for obedientiaries, monks who held specific posts within the monastery.

Islamic gardens were built after the model of Persian gardens and they were usually enclosed by walls and divided in four by watercourses. Commonly, the centre of the garden would have a reflecting pool or pavilion. Specific to the Islamic gardens are the mosaics and glazed tiles used to decorate the rills and fountains that were built in these gardens.

By the late 13th century, rich Europeans began to grow gardens for leisure and for medicinal herbs and vegetables. They surrounded the gardens by walls to protect them from animals and to provide seclusion. During the next two centuries, Europeans started planting lawns and raising flowerbeds and trellises of roses. Fruit trees were common in these gardens and also in some, there were turf seats. At the same time, the gardens in the monasteries were a place to grow flowers and medicinal herbs but they were also a space where the monks could enjoy nature and relax.

The gardens in the 16th and 17th century were symmetric, proportioned and balanced with a more classical appearance. Most of these gardens were built around a central axis and they were divided into different parts by hedges. Commonly, gardens had flowerbeds laid out in squares and separated by gravel paths.

Gardens in Renaissance were adorned with sculptures, topiary and fountains. In the 17th century, knot gardens became popular along with the hedge mazes. By this time, Europeans started planting new flowers such as tulips, marigolds and sunflowers.

Cottage gardens

Cottage gardens, which emerged in Elizabethan times, appear to have originated as a local source for herbs and fruits. One theory is that they arose out of the Black Death of the 1340s, when the death of so many laborers made land available for small cottages with personal gardens. According to the late 19th-century legend of origin, these gardens were originally created by the workers that lived in the cottages of the villages, to provide them with food and herbs, with flowers planted among them for decoration. Farm workers were provided with cottages that had architectural quality set in a small garden—about 1 acre—where they could grow food and keep pigs and chickens.

Authentic gardens of the yeoman cottager would have included a beehive and livestock, and frequently a pig and sty, along with a well. The peasant cottager of medieval times was more interested in meat than flowers, with herbs grown for medicinal use rather than for their beauty. By Elizabethan times there was more prosperity, and thus more room to grow flowers. Even the early cottage garden flowers typically had their practical use—violets were spread on the floor (for their pleasant scent and keeping out vermin); calendulas and primroses were both attractive and used in cooking. Others, such as sweet William and hollyhocks, were grown entirely for their beauty.

18th century

In the 18th century, gardens were laid out more naturally, without any walls. This style of smooth undulating grass, which would run straight to the house, clumps, belts and scattering of trees and serpentine lakes formed by invisibly damming small rivers, were a new style within the English landscape. This was a "gardenless" form of landscape gardening, which swept away almost all the remnants of previous formally patterned styles. The English landscape garden usually included a lake, lawns set against groves of trees, and often contained shrubberies, grottoes, pavilions, bridges and follies such as mock temples, Gothic ruins, bridges, and other picturesque architecture, designed to recreate an idyllic pastoral landscape. This new style emerged in England in the early 18th century, and spread across Europe, replacing the more formal, symmetrical garden à la française of the 17th century as the principal gardening style of Europe. The English garden presented an idealized view of nature. They were often inspired by paintings of landscapes by Claude Lorraine and Nicolas Poussin, and some were Influenced by the classic Chinese gardens of the East, which had recently been described by European travelers. The work of Lancelot 'Capability' Brown was particularly influential. Also, in 1804 the Horticultural Society was formed.

Gardens of the 19th century contained plants such as the monkey puzzle or Chile pine. This is also the time when the so-called "gardenesque" style of gardens evolved. These gardens displayed a wide variety of flowers in a rather small space. Rock gardens increased in popularity in the 19th century.

In ancient India, patterns from sacred geometry and mandalas were used to design gardens. Distinct mandala patterns denoted specific deities, planets, or even constellations. Such a garden was also referred to as a 'Mandala Vaatika'. The word 'Vaatika' can mean garden, plantation or parterre.

Types
Residential gardening takes place near the home, in a space referred to as the garden. Although a garden typically is located on the land near a residence, it may also be located on a roof, in an atrium, on a balcony, in a window box, on a patio or vivarium. Gardening also takes place in non-residential green areas, such as parks, public or semi-public gardens (botanical gardens or zoological gardens), amusement parks, along transportation corridors, and around tourist attractions and garden hotels. In these situations, a staff of gardeners or groundskeepers maintains the gardens.
 * Indoor gardening is concerned with the growing of houseplants within a residence or building, in a conservatory, or in a greenhouse. Indoor gardens are sometimes incorporated as part of air conditioning or heating systems. Indoor gardening extends the growing season in the fall and spring and can be used for winter gardening.
 * Native plant gardening is concerned with the use of native plants with or without the intent of creating wildlife habitat. The goal is to create a garden in harmony with, and adapted to a given area. This type of gardening typically reduces water usage, maintenance, and fertilization costs, while increasing native faunal interest.
 * Water gardening is concerned with growing plants adapted to pools and ponds. Bog gardens are also considered a type of water garden. These all require special conditions and considerations. A simple water garden may consist solely of a tub containing the water and plant(s). In aquascaping, a garden is created within an aquarium tank.
 * Container gardening is concerned with growing plants in any type of container either indoors or outdoors. Common containers are pots, hanging baskets, and planters. Container gardening is usually used in atriums and on balconies, patios, and roof tops.
 * Hügelkultur is concerned with growing plants on piles of rotting wood, as a form of raised bed gardening and composting in situ. An English loanword from German, it means "mound garden". Toby Hemenway, noted permaculture author and teacher, considers wood buried in trenches to also be a form of hugelkultur referred to as a dead wood swale. Hugelkultur is practiced by Sepp Holzer as a method of forest gardening and agroforestry, and by Geoff Lawton as a method of dryland farming and desert greening. When used as a method of disposing of large volumes of waste wood and woody debris, hugelkultur accomplishes carbon sequestration. It is also a form of xeriscaping.
 * Community gardening is a social activity in which an area of land is gardened by a group of people, providing access to fresh produce, herbs, flowers and plants as well as access to satisfying labor, neighborhood improvement, sense of community and connection to the environment. Community gardens are typically owned in trust by local governments or nonprofits.
 * Garden sharing partners landowners with gardeners in need of land. These shared gardens, typically front or back yards, are usually used to produce food that is divided between the two parties.
 * Organic gardening uses natural, sustainable methods, fertilizers and pesticides to grow non-genetically modified crops.
 * Biodynamic gardening or biodynamic agriculture is similar to organic gardening, but includes various esoteric concepts drawn from the ideas of Rudolf Steiner, such as astrological sowing and planting calendar and particular field and compost preparations.
 * Commercial gardening is a more intensive type of gardening that involves the production of vegetables, non-tropical fruits, and flowers from local farmers. Commercial gardening began because farmers would sell locally to stop food from spoiling faster because of the transportation of goods from a far distance. Mediterranean agriculture is also a common practice that commercial gardeners use. Mediterranean agriculture is the practice of cultivating animals such as sheep to help weed and provide manure for vine crops, grains, or citrus. Gardeners can easily train these animals to not eat the actual plant.
 * No-dig gardening (or no till gardening) is a method of gardening that avoids tillage as much as possible. This method of gardening is gaining popularity in part due to celebrated figures such as Charles Dowding, Masanobu Fukuoka, Jean-Martin Fortier, Connor Crickmore, Jesse Frost, Elaine Ingham, and many other market gardeners. Minimal tillage has been documented to help with promoting diverse soil biology, water retention and drainage, healthier vigorous plants, reduction in weed pressure, reduction in labor, increased fertility and nutrient availability, increase carbon sequestration, reduction in cost, reduction in soil erosion, and reduction in pollution.

Tools
Regardless of historical time period, location, scale, or type of garden, all gardening requires some basic tools. For the majority of human history, people have managed with significantly fewer resources compared to modern times. Agriculture was built on the use of hands, stones, sticks, human ingenuity, and fire. The essential tools used in pre-Bronze Age gardening were non-metal (primarily stone, bone, wood, or copper) knives, axes, adzes, foot ploughs, sickles, hoes, baskets, pottery, digging sticks, animal-driven ploughs, animals, and fire for clearing land. Up until the green revolution these simple tools, although continually improved upon, would continue to be the backbone of agricultural societies. The industrial revolution created a large increase in availability and impact of agricultural tools. These tools include tractors with modern implements, manure spreaders, cultivators, mowers, earth-moving machines, hedge trimmers, strimmer's, wood-chippers, two-wheel tractors, complex irrigation systems, plastic mulch, plastic shelters, seeding trays, indoor grow lights, packaging, chemical fertilizers, pesticides, genetically modified seeds, and many more.

Plant Propagation
Plants may be propagated through many different methods. These methods are classified as either sexual or asexual propagation.

Asexual reproduction
Asexual reproduction occurs when plants produce clonal offspring. This method of reproduction is often more simplistic and provides rapid population growth. Cloning may result in highly vulnerable plant populations if they do not also reproduce sexually in order to create genetic diversity thus allowing for certain levels of natural selection and hybrid vigor. There are various methods of asexual plant propagation taken advantage of by gardeners. These include vegetative propagation which involves the growth of new plants from vegetative parts of the parent plant, such as roots, stems, and leaves. Certain plants such as strawberries and raspberries produce stolons or rhizomes which are stems which grow horizontally above or below ground, developing new plants at nodes. Another common method of asexual reproduction in garden plants is fragmentation which involves a separation from the parent plant. This is common for shrubs, and trees such as willows which may shed their branches which is termed cladoptosis. Placing the shed limb into water or soil produces budding and causes roots to form. Perhaps the most commonly-known method of asexual reproduction in gardening and farming is grafting. A human may chose to graft an excellent fruit producing cultivar on a selected rootstock cultivar of the same species. This involves cutting each plant and connecting the cuttings by mechanical means until they inosculate or fuse together. Grafting is done for many purposes. Firstly, the scion (portion of the plant above the graft site) can undergo artificial selection for specific desirable traits such as flavor while the rootstock can undergo selection for traits such as disease resistance or cold tolerance. This effectively allows for much more efficiency in the artificial selection process as certain traits such as fruit taste can be ignored altogether in the rootstock allowing for a focused selection with less backcrossing to a plant that had good tasting fruit. Secondly, grafting allows for plants that require cross pollination for fruit generation, such as apples, to all grow together as one tree. Thirdly, this allows for quick reproduction where one mother plant can produce many semi-developed clones each year.

Sexual reproduction
Sexual reproduction occurs through the pollination of a ovule. This pollination must occur between female and male parts of a single flower or between flowers. A plant may undergo self pollination as a sexual means of reproduction where the genes of the mother plant will not perfectly match those of the progeny. Progeny from self pollination will however have less genetic diversity which may result in inbreeding depression versus plants from cross pollination. Pollen is typically carried by wind, insects, or animals to complete pollination. Some greenhouses may have to manually pollinate their plants to produce fruit and seeds due to a lack of these conditions. Sexual reproduction can only be done by members of the same species and this produces varying levels of genetic diversity in the plants offspring. This genetic diversity is responsible for the survival of every plant as we know them today. The diversity allows for disease resistance, adaptations to changing climate, changes in soil, changes in pollination methods, changes in animal grazing pressure, changes in weed pressure, and any other variations that arise in their growing conditions. Crossing plants, or hybridizing, results in hybrid vigor and will increase the genetic diversity. Many commercially grown plants are F1 hybrids which ensures certain desirable traits. A common alternative to growing hybrid plants is to grow heirloom or open pollinated plants which, unlike F1 hybrids, will produce viable seed with progeny similar to its parent. Many modern gardeners will save seeds from heirloom varieties but not hybrids due to the certainty of desirable traits heirloom seeds provide. Historically a lack of plant breeding knowledge would have led to more hybridization and the creation of new genetically diverse landraces. Each plant varies in its likelihood of outcrossing. Highly outcrossing plants such as spinach are more likely to create landraces. Many landraces and heirloom varieties along with their genetics are being lost due to the decrease in seed saving by modern farmers. This leads plant geneticists to search for desirable genetics in wild ancestral varieties of commonly grown plants. Plants have been artificially selected and bred since at least 7800 BCE. Despite the decrease in farmer seed saving, many landraces are also being created through artificial selection and genetic modification. Gardeners remain vital in the preservation of diverse genetics whether they maintain a family heirloom variety bred to fit conditions from the distant past, or they breed new landraces with traits matching their modern climate and growing condition.

Certain seeds may not sprout without certain environmental conditions. These seeds either require scarification or stratification. Gardeners may grow frustrated if they lack this crucial knowledge before attempting to propagate certain plants such as hard neck garlic (asexual reproduction), which requires a cold dormant period to sprout, or saskatoon berries which have improved germination after being digested by bears through a process called endozoochory.

Transplanting
Many gardeners, especially those who live in colder climates, will start seeds indoors prior to transplanting the young plant outside. This provides many benefits such as elongating the growing season, ensuring adequate quantities and quality of light, ensuring seedlings have adequate nutrients in the seed starting mix, ensuring seeds stay at correct humidity, heat, and moisture level for germination, and saving space in the garden. Many crops will not be harvestable unless they are started inside so if a gardener wants to plant these crops in their garden without starting the plants themselves, they will need to purchase transplants which are commonly available at garden centers, plant nurseries, and big-box stores. It is crucial that transplanting is done correctly. This generally implies providing the plants with enough soil so they do not become root-bound (roots wrapping in circles around transplant container), providing a hardening-off period (slow exposure to sun, wind, and cold), providing sufficient light, water, and nutrients, and choosing the correct plants to start indoors as some plants do not do well with the transplanting process.

There are varying methods of starting your seeds. The most prevalent method would be to start seeds in transplant (plug) trays or in planters/pots. Another method is starting seeds in soil blocks (small cubes of compressed potting soil, compost, and/or other seed-starting media), which may reduce transplant shock and stop root-binding because they allow air pruning of the roots. Some plants such as onions and various herbs may be efficiently started by scattering their seeds on top of soil in a large tray where the seedlings will later be teased apart from each other and replanted in the garden or pots.

Pests
Garden pests are generally plants, fungi, or animals (frequently insects) that engage in activity that the gardener considers undesirable. A pest may crowd out desirable plants, disturb soil, stunt the growth of young seedlings, steal or damage fruit, or otherwise kill plants, hamper their growth, damage their appearance, or reduce the quality of the edible or ornamental portions of the plant. Aphids, spider mites, slugs, snails, ants, birds, and even cats are commonly considered to be garden pests.

Throughout history ecosystems that have undergone rapid changes are typically those which harbor the most pests. For example, a highly and rapidly altered landscape such as modern canola fields in the Americas can be a breeding ground for pests of the Brassicaceae family. A natural ecosystem will typically regulate pest levels through many biological means whether that be the natural introduction of a disease or an increase in the population of a predator species of animal. Because gardeners may have different goals, organisms considered "garden pests" vary from gardener to gardener. Tropaeolum speciosum, for example, may be considered a desirable and ornamental garden plant, or it may be considered a pest if it seeds and starts to grow where it is not wanted. As another example, in lawns, moss can become dominant and be impossible to eradicate. In some lawns, lichens, especially very damp lawn lichens such as Peltigera lactucfolia and P. membranacea, can become difficult to control and are considered pests.

Pest control
There are many ways by which unwanted pests are removed from a garden. The techniques vary depending on the pest, the gardener's goals, and the gardener's philosophy. For example, snails may be dealt with through the use of a chemical pesticide, an organic pesticide, hand-picking, barriers, or simply growing snail-resistant plants.

On a large scale pest control is often done through the use of pesticides and herbicides, which may be either organic or artificially synthesized. Pesticides may affect the ecology of a garden due to their effects on the populations of both target and non-target species. For example, unintended exposure to some neonicotinoid pesticides has been proposed as a factor in the recent decline in honey bee populations. Pesticides and herbicides are also known to cause medical issues, typically to those in proximity during their application. While farm workers are by far the most affected by the use of pesticides and herbicides, they are often under-informed or accept the consequences due to financial necessity. Fungicides may be applied to the seed coat to reduce mortality of germinating seedlings. The improper use of pesticides often leads to pesticide resistance which poses a risk in global food security. With climate change affecting the distribution of pests, a global increase in pesticide usage has been observed which in turn has caused an increase of human health risks due to exposure. Creating new pesticides in order to manage resistant organisms is an immense expense and is often heavily criticized as an ineffective method of pest control. Other means of control include the removal of infected plants, using fertilizers and bio stimulants to improve the health and vigor of plants so they better resist attack, practicing crop rotation to prevent pest build-up, using foliar sprays, companion planting, and practicing good garden hygiene, such as disinfecting tools and clearing debris and weeds which may harbor pests. Another common method of pest control, used frequently in market gardening, is using insect netting or plastic greenhouse covers. Gardeners may rely on one type of pest in order to eliminate another. Some examples of this are cats which hunt mice and rats, wild birds, bats, chickens, and ducks which hunt insects and slugs, or thorny hedges to deter deer and other creatures. Using these organisms to help control pests is called biological pest control. There are also targeted measures of animal pest control such as a mole vibrator which can deter mole activity in a garden, or automated gun shots to scare off birds.

Garden guns
Garden guns are smooth-bore shotguns specifically made to fire .22 caliber snake shot, and are commonly used by gardeners and farmers for pest control. Garden guns are short-range weapons that can do little harm past 15 to 20 yard and are relatively quiet when fired with snake shot, compared to a standard ammunition. These guns are especially effective inside of barns and sheds, as the snake shot will not shoot holes in the roof or walls, or more importantly injure livestock with a ricochet. They are also used for pest control at airports, warehouses, and stockyards.

Social aspects
People can express their political or social views in gardens, intentionally or not. The lawn vs. garden issue is played out in urban planning as the debate over the "land ethic" that is to determine urban land use and whether hyper hygienist bylaws (e.g. weed control) should apply, or whether land should generally be allowed to exist in its natural wild state. In a famous Canadian Charter of Rights case, "Sandra Bell vs. City of Toronto", 1997, the right to cultivate all native species, even most varieties deemed noxious or allergenic, was upheld as part of the right of free expression.

Community gardening comprises a wide variety of approaches to sharing land and gardens.

People often surround their house and garden with a hedge. Common hedge plants are privet, hawthorn, beech, yew, leyland cypress, hemlock, arborvitae, barberry, box, holly, oleander, forsythia and lavender. The idea of open gardens without hedges may be distasteful to those who enjoy privacy. The Slow Food movement has sought in some countries to add an edible school yard and garden classrooms to schools, e.g. in Fergus, Ontario, where these were added to a public school to augment the kitchen classroom. Garden sharing, where urban landowners allow gardeners to grow on their property in exchange for a share of the harvest, is associated with the desire to control the quality of one's food, and reconnect with soil and community.

In US and British usage, the production of ornamental plantings around buildings is called landscaping, landscape maintenance or grounds keeping, while international usage uses the term gardening for these same activities.

Also gaining popularity is the concept of "Green Gardening" which involves growing plants using organic fertilizers and pesticides so that the gardening process – or the flowers and fruits produced thereby – doesn't adversely affect the environment or people's health in any manner.

Gardening can be a very pleasant and relaxing activity with rewarding results. it allows for a connection with nature and creating a green space that presents a vision of beauty but also contributes to the eco system. A thriving and flourishing garden can be created, by understanding and adapting to the climate and environmental changes.

plants and flowers grow in varying temperatures and weather conditions. Most plants thrive in temperatures between 18 and 24 °C during the day and slightly cooler at night. This range allows for optimal photosynthesis and overall growth for many common plant species. Usually there is a variety of plants in a garden, therefore it is always best to learn about the best weather for your plants to have success with your planting.

Laws and restrictions
In some parts of the world, particularly the United States, gardening can be restricted by law or by rules and regulations imposed by a home-owner's association. In the United States, such rules may prohibit homeowners from growing vegetable gardens, prohibit xeriscaping or meadow gardens, or require garden plants to be chosen from a pre-approved list, to preserve the aesthetics of the neighborhood. Numerous challenges to these laws, ordinances and regulations have emerged in recent years, with some resulting in legislation protecting a homeowner's right to cultivate native plants or grow vegetables. Laws protecting a homeowner's right to grow food plants have been termed "right to garden" laws.

Benefits
Gardening is considered by many people to be a relaxing activity. There are also many studies about the positive effects on mental and physical health in relation to gardening. Specifically, gardening is thought to increase self-esteem and reduce stress. As writer and former teacher Sarah Biddle notes, one's garden may become a "tiny oasis to relax and recharge [one's] batteries." Involving in gardening activities aid in creativity, observational skills, learning, planning and physical movement.

Others consider gardening to be a good hedge against supply chain disruptions with increased worries that the public cannot always trust that the grocery store shelves will be fully stocked. In April 2022, about 31% of grocery products were out of stock which is an 11% increase from November 2021.

Gardening can also support good numbers and a wide range of pollinators, but worryingly bees and other pollinators are in decline. Gardeners can make a difference to help reverse this trend. The main thing that matters is that they get their share of nectar to fuel their busy lifestyles, and this is where gardening can help them.

A way to both positively impacts humans and pollinators can be implementing pollinator gardens. Including native flowers has shown to increase pollinators, and even protects bee populations against urbanization and landscapes that do not include flowers. Small patches in urban landscapes that are diverse in flowers have been noted to match or even exceed wild landscapes when it comes to bees pollinating. Areas like golf courses, cemeteries, community gardens as well as residential gardens are all areas in urban settings that could benefit pollinator diversity by implementing native flowers to the landscape.

Ornaments and accessories

There is a wide range of garden ornaments and accessories available in the market for both the professional gardener and the amateur to exercise their creativity for example sculptures, lights or fountains. These are used to add decoration or functionality, and may be made from a wide range of materials such as copper, stone, wood, bamboo, stainless steel, clay, stained glass, concrete, or iron. Examples include trellis, garden furniture, gnomes, statues, outdoor fireplaces, fountains, rain chains, urns, bird baths and feeders, wind chimes, and garden lighting such as candle lanterns and oil lamps. The use of these items can be part of the expression of a gardener's gardening personality.

As art
Garden design is considered to be an art in most cultures, distinguished from gardening, which generally means garden maintenance. Garden design can include different themes such as perennial, butterfly, wildlife, Japanese, water, tropical, or shade gardens.

In Japan, Samurai and Zen monks were often required to build decorative gardens or practice related skills like flower arrangement known as ikebana. In 18th-century Europe, country estates were refashioned by landscape gardeners into formal gardens or landscaped park lands, such as at Versailles, France, or Stowe, England. Today, landscape architects and garden designers continue to produce artistically creative designs for private garden spaces. In the US, professional landscape designers are certified by the Association of Professional Landscape Designers.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Gardening


text:
Graffiti

Graffiti (plural; singular graffiti or graffito, the latter rarely used except in archeology) is art that is written, painted or drawn on a wall or other surface, usually without permission and within public view. Graffiti ranges from simple written "monikers" to elaborate wall paintings, and has existed since ancient times, with examples dating back to ancient Egypt, ancient Greece, and the Roman Empire (see also mural).

Graffiti is a controversial subject. In most countries, marking or painting property without permission is considered by property owners and civic authorities as defacement and vandalism, which is a punishable crime, citing the use of graffiti by street gangs to mark territory or to serve as an indicator of gang-related activities. Graffiti has become visualized as a growing urban "problem" for many cities in industrialized nations, spreading from the New York City subway system and Philadelphia in the early 1970s to the rest of the United States and Europe and other world regions.

Etymology
"Graffiti" (usually both singular and plural) and the rare singular form "graffito" are from the Italian word graffiato ("scratched"). The term "graffiti" is used in art history for works of art produced by scratching a design into a surface. A related term is "sgraffito", which involves scratching through one layer of pigment to reveal another beneath it. This technique was primarily used by potters who would glaze their wares and then scratch a design into them. In ancient times graffiti were carved on walls with a sharp object, although sometimes chalk or coal were used. The word originates from Greek γράφειν—graphein—meaning "to write".

History

The term graffiti originally referred to the inscriptions, figure drawings, and such, found on the walls of ancient sepulchres or ruins, as in the Catacombs of Rome or at Pompeii. Historically, these writings were not considered vandalism, which today is considered part of the definition of graffiti.

The only known source of the Safaitic language, an ancient form of Arabic, is from graffiti: inscriptions scratched on to the surface of rocks and boulders in the predominantly basalt desert of southern Syria, eastern Jordan and northern Saudi Arabia. Safaitic dates from the first century BC to the fourth century AD.

Ancient graffiti
Some of the oldest cave paintings in the world are 40,000 year old ones found in Australia. The oldest written graffiti was found in ancient Rome around 2500 years ago. Most graffiti from the time was boasts about sexual experiences. Graffiti in Ancient Rome was a form of communication, and was not considered vandalism.

Ancient tourists visiting the 5th-century citadel at Sigiriya in Sri Lanka write their names and commentary over the "mirror wall", adding up to over 1800 individual graffiti produced there between the 6th and 18th centuries. Most of the graffiti refer to the frescoes of semi-nude females found there. One reads:

Among the ancient political graffiti examples were Arab satirist poems. Yazid al-Himyari, an Umayyad Arab and Persian poet, was most known for writing his political poetry on the walls between Sajistan and Basra, manifesting a strong hatred towards the Umayyad regime and its walis, and people used to read and circulate them very widely.

Graffiti, known as Tacherons, were frequently scratched on Romanesque Scandinavian church walls. When Renaissance artists such as Pinturicchio, Raphael, Michelangelo, Ghirlandaio, or Filippino Lippi descended into the ruins of Nero's Domus Aurea, they carved or painted their names and returned to initiate the grottesche style of decoration.

There are also examples of graffiti occurring in American history, such as Independence Rock, a national landmark along the Oregon Trail.

Contemporary graffiti
Later, French soldiers carved their names on monuments during the Napoleonic campaign of Egypt in the 1790s. Lord Byron's survives on one of the columns of the Temple of Poseidon at Cape Sounion in Attica, Greece.

The oldest known example of graffiti monikers found on traincars created by hobos and railworkers since the late 1800s. The Bozo Texino monikers were documented by filmmaker Bill Daniel in his 2005 film, Who is Bozo Texino?.

In World War II, an inscription on a wall at the fortress of Verdun was seen as an illustration of the US response twice in a generation to the wrongs of the Old World:

During World War II and for decades after, the phrase "Kilroy was here" with an accompanying illustration was widespread throughout the world, due to its use by American troops and ultimately filtering into American popular culture. Shortly after the death of Charlie Parker (nicknamed "Yardbird" or "Bird"), graffiti began appearing around New York with the words "Bird Lives".

Modern Graffiti
Modern graffiti art has its origins with young people in 1960s and 70s in New York City and Philadelphia. Tags were the first form of stylised contemporary graffiti. Eventually, throw-ups and pieces evolved with the desire to create larger art. Writers used spray paint and other kind of materials to leave tags or to create images on the sides subway trains. and eventually moved into the city after the NYC metro began to buy new trains and paint over graffiti.

While the art had many advocates and appreciators—including the cultural critic Norman Mailer—others, including New York City mayor Ed Koch, considered it to be defacement of public property, and saw it as a form of public blight. The ‘taggers’ called what they did ‘writing’—though an important 1974 essay by Mailer referred to it using the term ‘graffiti.’

Contemporary graffiti style has been heavily influenced by hip hop culture and the myriad international styles derived from Philadelphia and New York City Subway graffiti; however, there are many other traditions of notable graffiti in the twentieth century. Graffiti have long appeared on building walls, in latrines, railroad boxcars, subways, and bridges.

An early graffito outside of New York or Philadelphia was the inscription in London reading "Clapton is God" in reference to the guitarist Eric Clapton. Creating the cult of the guitar hero, the phrase was spray-painted by an admirer on a wall in Islington, north London, in the autumn of 1967. The graffito was captured in a photograph, in which a dog is urinating on the wall.

Films like Style Wars in the 80s depicting famous writers such as Skeme, Dondi, MinOne, and ZEPHYR reinforced graffiti's role within New York's emerging hip-hop culture. Although many officers of the New York City Police Department found this film to be controversial, Style Wars is still recognized as the most prolific film representation of what was going on within the young hip hop culture of the early 1980s. Fab5 Freddy and Futura 2000 took hip hop graffiti to Paris and London as part of the New York City Rap Tour in 1983.

Commercialization and entrance into mainstream pop culture
With the popularity and legitimization of graffiti has come a level of commercialization. In 2001, computer giant IBM launched an advertising campaign in Chicago and San Francisco which involved people spray painting on sidewalks a peace symbol, a heart, and a penguin (Linux mascot), to represent "Peace, Love, and Linux." IBM paid Chicago and San Francisco collectively US$120,000 for punitive damages and clean-up costs.

In 2005, a similar ad campaign was launched by Sony and executed by its advertising agency in New York, Chicago, Atlanta, Philadelphia, Los Angeles, and Miami, to market its handheld PSP gaming system. In this campaign, taking notice of the legal problems of the IBM campaign, Sony paid building owners for the rights to paint on their buildings "a collection of dizzy-eyed urban kids playing with the PSP as if it were a skateboard, a paddle, or a rocking horse".

South America
Tristan Manco wrote that Brazil "boasts a unique and particularly rich, graffiti scene ... [earning] it an international reputation as the place to go for artistic inspiration". Graffiti "flourishes in every conceivable space in Brazil's cities". Artistic parallels "are often drawn between the energy of São Paulo today and 1970s New York". The "sprawling metropolis", of São Paulo has "become the new shrine to graffiti"; Manco alludes to "poverty and unemployment ... [and] the epic struggles and conditions of the country's marginalised peoples", and to "Brazil's chronic poverty", as the main engines that "have fuelled a vibrant graffiti culture". In world terms, Brazil has "one of the most uneven distributions of income. Laws and taxes change frequently". Such factors, Manco argues, contribute to a very fluid society, riven with those economic divisions and social tensions that underpin and feed the "folkloric vandalism and an urban sport for the disenfranchised", that is South American graffiti art.

Prominent Brazilian writers include Os Gêmeos, Boleta, Nunca, Nina, Speto, Tikka, and T.Freak. Their artistic success and involvement in commercial design ventures has highlighted divisions within the Brazilian graffiti community between adherents of the cruder transgressive form of pichação and the more conventionally artistic values of the practitioners of grafite.

Middle East
Graffiti in the Middle East has emerged slowly, with taggers operating in Egypt, Lebanon, the Gulf countries like Bahrain or the United Arab Emirates, Israel, and in Iran. The major Iranian newspaper Hamshahri has published two articles on illegal writers in the city with photographic coverage of Iranian artist A1one's works on Tehran walls. Tokyo-based design magazine, PingMag, has interviewed A1one and featured photographs of his work. The Israeli West Bank barrier has become a site for graffiti, reminiscent in this sense of the Berlin Wall. Many writers in Israel come from other places around the globe, such as JUIF from Los Angeles and DEVIONE from London. The religious reference "נ נח נחמ נחמן מאומן" ("Na Nach Nachma Nachman Meuman") is commonly seen in graffiti around Israel.

Graffiti has played an important role within the street art scene in the Middle East and North Africa (MENA), especially following the events of the Arab Spring of 2011 or the Sudanese Revolution of 2018/19. Graffiti is a tool of expression in the context of conflict in the region, allowing people to raise their voices politically and socially. Famous street artist Banksy has had an important effect in the street art scene in the MENA area, especially in Palestine where some of his works are located in the West Bank barrier and Bethlehem.

Southeast Asia
There are also a large number of graffiti influences in Southeast Asian countries that mostly come from modern Western culture, such as Malaysia, where graffiti have long been a common sight in Malaysia's capital city, Kuala Lumpur. Since 2010, the country has begun hosting a street festival to encourage all generations and people from all walks of life to enjoy and encourage Malaysian street culture.

Methods and production
The modern-day graffitists can be found with an arsenal of various materials that allow for a successful production of a piece. This includes such techniques as scribing. However, spray paint in aerosol cans is the number one medium for graffiti. From this commodity comes different styles, technique, and abilities to form master works of graffiti. Spray paint can be found at hardware and art stores and comes in virtually every color.

Stencil graffiti
Stencil graffiti is created by cutting out shapes and designs in a stiff material (such as cardboard or subject folders) to form an overall design or image. The stencil is then placed on the "canvas" gently and with quick, easy strokes of the aerosol can, the image begins to appear on the intended surface.

Some of the first examples were created in 1981 by artists Blek le Rat in Paris, in 1982 by Jef Aerosol in Tours (France); by 1985 stencils had appeared in other cities including New York City, Sydney, and Melbourne, where they were documented by American photographer Charles Gatewood and Australian photographer Rennie Ellis.

Tagging
Tagging is the practice of someone spray-painting "their name, initial or logo onto a public surface" in a handstyle unique to the writer. Tags were the first form of modern graffiti. A number of recent examples of graffiti make use of hashtags.

Modern experimentation

Modern graffiti art often incorporates additional arts and technologies. For example, Graffiti Research Lab has encouraged the use of projected images and magnetic light-emitting diodes (throwies) as new media for graffitists. yarnbombing is another recent form of graffiti. Yarnbombers occasionally target previous graffiti for modification, which had been avoided among the majority of graffitists.

Uses
Theories on the use of graffiti by avant-garde artists have a history dating back at least to the Asger Jorn, who in 1962 painting declared in a graffiti-like gesture "the avant-garde won't give up".

Many contemporary analysts and even art critics have begun to see artistic value in some graffiti and to recognize it as a form of public art. According to many art researchers, particularly in the Netherlands and in Los Angeles, that type of public art is, in fact an effective tool of social emancipation or, in the achievement of a political goal.

In times of conflict, such murals have offered a means of communication and self-expression for members of these socially, ethnically, or racially divided communities, and have proven themselves as effective tools in establishing dialog and thus, of addressing cleavages in the long run. The Berlin Wall was also extensively covered by graffiti reflecting social pressures relating to the oppressive Soviet rule over the GDR.

Many artists involved with graffiti are also concerned with the similar activity of stenciling. Essentially, this entails stenciling a print of one or more colors using spray-paint. Recognized while exhibiting and publishing several of her coloured stencils and paintings portraying the Sri Lankan Civil War and urban Britain in the early 2000s, graffitists Mathangi Arulpragasam, aka M.I.A., has also become known for integrating her imagery of political violence into her music videos for singles "Galang" and "Bucky Done Gun", and her cover art. Stickers of her artwork also often appear around places such as London in Brick Lane, stuck to lamp posts and street signs, she having become a muse for other graffitists and painters worldwide in cities including Seville.

Graffitist believes that art should be on display for everyone in the public eye or in plain sight, not hidden away in a museum or a gallery. Art should color the streets, not the inside of some building. Graffiti is a form of art that cannot be owned or bought. It does not last forever, it is temporary, yet one of a kind. It is a form of self promotion for the artist that can be displayed anywhere from sidewalks, roofs, subways, building wall, etc. Art to them is for everyone and should be showed to everyone for free.

Personal expression
Graffiti is a way of communicating and a way of expressing what one feels in the moment. It is both art and a functional thing that can warn people of something or inform people of something. However, graffiti is to some people a form of art, but to some a form of vandalism. And many graffitists choose to protect their identities and remain anonymous or to hinder prosecution.

With the commercialization of graffiti (and hip hop in general), in most cases, even with legally painted "graffiti" art, graffitists tend to choose anonymity. This may be attributed to various reasons or a combination of reasons. Graffiti still remains the one of four hip hop elements that is not considered "performance art" despite the image of the "singing and dancing star" that sells hip hop culture to the mainstream. Being a graphic form of art, it might also be said that many graffitists still fall in the category of the introverted archetypal artist.

Banksy is one of the world's most notorious and popular street artists who continues to remain faceless in today's society. He is known for his political, anti-war stencil art mainly in Bristol, England, but his work may be seen anywhere from Los Angeles to Palestine. In the UK, Banksy is the most recognizable icon for this cultural artistic movement and keeps his identity a secret to avoid arrest. Much of Banksy's artwork may be seen around the streets of London and surrounding suburbs, although he has painted pictures throughout the world, including the Middle East, where he has painted on Israel's controversial West Bank barrier with satirical images of life on the other side. One depicted a hole in the wall with an idyllic beach, while another shows a mountain landscape on the other side. A number of exhibitions also have taken place since 2000, and recent works of art have fetched vast sums of money. Banksy's art is a prime example of the classic controversy: vandalism vs. art. Art supporters endorse his work distributed in urban areas as pieces of art and some councils, such as Bristol and Islington, have officially protected them, while officials of other areas have deemed his work to be vandalism and have removed it.

Pixnit is another artist who chooses to keep her identity from the general public. Her work focuses on beauty and design aspects of graffiti as opposed to Banksy's anti-government shock value. Her paintings are often of flower designs above shops and stores in her local urban area of Cambridge, Massachusetts. Some store owners endorse her work and encourage others to do similar work as well. "One of the pieces was left up above Steve's Kitchen, because it looks pretty awesome"- Erin Scott, the manager of New England Comics in Allston, Massachusetts.

Graffiti artists may become offended if photographs of their art are published in a commercial context without their permission. In March 2020, the Finnish graffiti artist Psyke expressed his displeasure at the newspaper Ilta-Sanomat publishing a photograph of a Peugeot 208 in an article about new cars, with his graffiti prominently shown on the background. The artist claims he does not want his art being used in commercial context, not even if he were to receive compensation.

Territorial
Territorial graffiti marks urban neighborhoods with tags and logos to differentiate certain groups from others. These images are meant to show outsiders a stern look at whose turf is whose. The subject matter of gang-related graffiti consists of cryptic symbols and initials strictly fashioned with unique calligraphies. Gang members use graffiti to designate membership throughout the gang, to differentiate rivals and associates and, most commonly, to mark borders which are both territorial and ideological.

As advertising
Graffiti has been used as a means of advertising both legally and illegally. Bronx-based TATS CRU has made a name for themselves doing legal advertising campaigns for companies such as Coca-Cola, McDonald's, Toyota, and MTV. In the UK, Covent Garden's Boxfresh used stencil images of a Zapatista revolutionary in the hopes that cross referencing would promote their store.

Smirnoff hired artists to use reverse graffiti (the use of high pressure hoses to clean dirty surfaces to leave a clean image in the surrounding dirt) to increase awareness of their product.

Radical and political

Graffiti often has a reputation as part of a subculture that rebels against authority, although the considerations of the practitioners often diverge and can relate to a wide range of attitudes. It can express a political practice and can form just one tool in an array of resistance techniques. One early example includes the anarcho-punk band Crass, who conducted a campaign of stenciling anti-war, anarchist, feminist, and anti-consumerist messages throughout the London Underground system during the late 1970s and early 1980s. In Amsterdam graffiti was a major part of the punk scene. The city was covered with names such as "De Zoot", "Vendex", and "Dr Rat". To document the graffiti a punk magazine was started that was called Gallery Anus. So when hip hop came to Europe in the early 1980s there was already a vibrant graffiti culture.

The student protests and general strike of May 1968 saw Paris bedecked in revolutionary, anarchistic, and situationist slogans such as L'ennui est contre-révolutionnaire ("Boredom is counterrevolutionary") and Lisez moins, vivez plus ("Read less, live more"). While not exhaustive, the graffiti gave a sense of the 'millenarian' and rebellious spirit, tempered with a good deal of verbal wit, of the strikers.

The developments of graffiti art which took place in art galleries and colleges as well as "on the street" or "underground", contributed to the resurfacing in the 1990s of a far more overtly politicized art form in the subvertising, culture jamming, or tactical media movements. These movements or styles tend to classify the artists by their relationship to their social and economic contexts, since, in most countries, graffiti art remains illegal in many forms except when using non-permanent paint. Since the 1990s with the rise of Street Art, a growing number of artists are switching to non-permanent paints and non-traditional forms of painting.

Contemporary practitioners, accordingly, have varied and often conflicting practices. Some individuals, such as Alexander Brener, have used the medium to politicize other art forms, and have used the prison sentences enforced on them as a means of further protest. The practices of anonymous groups and individuals also vary widely, and practitioners by no means always agree with each other's practices. For example, the anti-capitalist art group the Space Hijackers did a piece in 2004 about the contradiction between the capitalistic elements of Banksy and his use of political imagery.

Berlin human rights activist Irmela Mensah-Schramm has received global media attention and numerous awards for her 35-year campaign of effacing neo-Nazi and other right-wing extremist graffiti throughout Germany, often by altering hate speech in humorous ways.

Genocide denial
In Serbian capital, Belgrade, the graffiti depicting a uniformed former general of Serb army and war criminal, convicted at ICTY for war crimes and crimes against humanity, including genocide and ethnic cleansing in Bosnian War, Ratko Mladić, appeared in a military salute alongside the words "General, thank to your mother". Aleks Eror, Berlin-based journalist, explains how "veneration of historical and wartime figures" through street art is not a new phenomenon in the region of former Yugoslavia, and that "in most cases is firmly focused on the future, rather than retelling the past". Eror is not only analyst pointing to danger of such an expressions for the region's future. In a long expose on the subject of Bosnian genocide denial, at Balkan Diskurs magazine and multimedia platform website, Kristina Gadže and Taylor Whitsell referred to these experiences as a young generations' "cultural heritage", in which young are being exposed to celebration and affirmation of war-criminals as part of their "formal education" and "inheritance". There are numerous examples of genocide denial through celebration and affirmation of war criminals throughout the region of Western Balkans inhabited by Serbs using this form of artistic expression. Several more of these graffiti are found in Serbian capital, and many more across Serbia and Bosnian and Herzegovinian administrative entity, Republika Srpska, which is the ethnic Serbian majority enclave. Critics point that Serbia as a state, is willing to defend the mural of convicted war criminal, and have no intention to react on cases of genocide denial, noting that Interior Minister of Serbia, Aleksandar Vulin decision to ban any gathering with an intent to remove the mural, with the deployment of riot police, sends the message of "tacit endorsement". Consequently, on 9 November 2021, Serbian heavy police in riot gear, with graffiti creators and their supporters, blocked the access to the mural to prevent human rights groups and other activists to paint over it and mark the International Day Against Fascism and Antisemitism in that way, and even arrested two civic activist for throwing eggs at the graffiti.

Offensive graffiti

Graffiti may also be used as an offensive expression. This form of graffiti may be difficult to identify, as it is mostly removed by the local authority (as councils which have adopted strategies of criminalization also strive to remove graffiti quickly). Therefore, existing racist graffiti is mostly more subtle and at first sight, not easily recognized as "racist". It can then be understood only if one knows the relevant "local code" (social, historical, political, temporal, and spatial), which is seen as heteroglot and thus a 'unique set of conditions' in a cultural context.
 * A spatial code for example, could be that there is a certain youth group in an area that is engaging heavily in racist activities. So, for residents (knowing the local code), a graffiti containing only the name or abbreviation of this gang already is a racist expression, reminding the offended people of their gang activities. Also a graffiti is in most cases, the herald of more serious criminal activity to come. A person who does not know these gang activities would not be able to recognize the meaning of this graffiti. Also if a tag of this youth group or gang is placed on a building occupied by asylum seekers, for example, its racist character is even stronger.

By making the graffiti less explicit (as adapted to social and legal constraints), these drawings are less likely to be removed, but do not lose their threatening and offensive character.

Elsewhere, activists in Russia have used painted caricatures of local officials with their mouths as potholes, to show their anger about the poor state of the roads. In Manchester, England, a graffitists painted obscene images around potholes, which often resulted in them being repaired within 48 hours.

Decorative and high art

In the early 1980s, the first art galleries to show graffitists to the public were Fashion Moda in the Bronx, Now Gallery and Fun Gallery, both in the East Village, Manhattan.

A 2006 exhibition at the Brooklyn Museum displayed graffiti as an art form that began in New York's outer boroughs and reached great heights in the early 1980s with the work of Crash, Lee, Daze, Keith Haring, and Jean-Michel Basquiat. It displayed 22 works by New York graffitists, including Crash, Daze, and Lady Pink. In an article about the exhibition in the magazine Time Out, curator Charlotta Kotik said that she hoped the exhibition would cause viewers to rethink their assumptions about graffiti.

From the 1970s onwards, Burhan Doğançay photographed urban walls all over the world; these he then archived for use as sources of inspiration for his painterly works. The project today known as "Walls of the World" grew beyond even his own expectations and comprises about 30,000 individual images. It spans a period of 40 years across five continents and 114 countries. In 1982, photographs from this project comprised a one-man exhibition titled "Les murs murmurent, ils crient, ils chantent..." (The walls whisper, shout and sing...) at the Centre Georges Pompidou in Paris.

In Australia, art historians have judged some local graffiti of sufficient creative merit to rank them firmly within the arts. Oxford University Press's art history text Australian Painting 1788–2000 concludes with a long discussion of graffiti's key place within contemporary visual culture, including the work of several Australian practitioners.

Between March and April 2009, 150 artists exhibited 300 pieces of graffiti at the Grand Palais in Paris.

Environmental effects
Spray paint has many negative environmental effects. The paint contains toxic chemicals, and the can uses volatile hydrocarbon gases to spray the paint onto a surface.

Volatile organic compound (VOC) leads to ground level ozone formation and most of graffiti related emissions are VOCs. A 2010 paper estimates 4,862 tons of VOCs were released in the United States in activities related to graffiti.

Asia
In China, Mao Zedong in the 1920s used revolutionary slogans and paintings in public places to galvanize the country's communist movement.

Based on different national conditions, many people believe that China's attitude towards Graffiti is fierce, but in fact, according to Lance Crayon in his film Spray Paint Beijing: Graffiti in the Capital of China, Graffiti is generally accepted in Beijing, with artists not seeing much police interference. Political and religiously sensitive graffiti, however, is not allowed.

In Hong Kong, Tsang Tsou Choi was known as the King of Kowloon for his calligraphy graffiti over many years, in which he claimed ownership of the area. Now some of his work is preserved officially.

In Taiwan, the government has made some concessions to graffitists. Since 2005 they have been allowed to freely display their work along some sections of riverside retaining walls in designated "Graffiti Zones". From 2007, Taipei's department of cultural affairs also began permitting graffiti on fences around major public construction sites. Department head Yong-ping Lee (李永萍) stated, "We will promote graffiti starting with the public sector, and then later in the private sector too. It's our goal to beautify the city with graffiti". The government later helped organize a graffiti contest in Ximending, a popular shopping district. Graffitists caught working outside of these designated areas still face fines up to NT$6,000 under a department of environmental protection regulation. However, Taiwanese authorities can be relatively lenient, one veteran police officer stating anonymously, "Unless someone complains about vandalism, we won't get involved. We don't go after it proactively."

In 1993, after several expensive cars in Singapore were spray-painted, the police arrested a student from the Singapore American School, Michael P. Fay, questioned him, and subsequently charged him with vandalism. Fay pleaded guilty to vandalizing a car in addition to stealing road signs. Under the 1966 Vandalism Act of Singapore, originally passed to curb the spread of communist graffiti in Singapore, the court sentenced him to four months in jail, a fine of S$3,500 (US$2,233), and a caning. The New York Times ran several editorials and op-eds that condemned the punishment and called on the American public to flood the Singaporean embassy with protests. Although the Singapore government received many calls for clemency, Fay's caning took place in Singapore on 5 May 1994. Fay had originally received a sentence of six strokes of the cane, but the presiding president of Singapore, Ong Teng Cheong, agreed to reduce his caning sentence to four lashes.

In South Korea, Park Jung-soo was fined two million South Korean won by the Seoul Central District Court for spray-painting a rat on posters of the G-20 Summit a few days before the event in November 2011. Park alleged that the initial in "G-20" sounds like the Korean word for "rat", but Korean government prosecutors alleged that Park was making a derogatory statement about the president of South Korea, Lee Myung-bak, the host of the summit. This case led to public outcry and debate on the lack of government tolerance and in support of freedom of expression. The court ruled that the painting, "an ominous creature like a rat" amounts to "an organized criminal activity" and upheld the fine while denying the prosecution's request for imprisonment for Park.

Europe

In Europe, community cleaning squads have responded to graffiti, in some cases with reckless abandon, as when in 1992 in France a local Scout group, attempting to remove modern graffiti, damaged two prehistoric paintings of bison in the Cave of Mayrière supérieure near the French village of Bruniquel in Tarn-et-Garonne, earning them the 1992 Ig Nobel Prize in archeology.

In September 2006, the European Parliament directed the European Commission to create urban environment policies to prevent and eliminate dirt, litter, graffiti, animal excrement, and excessive noise from domestic and vehicular music systems in European cities, along with other concerns over urban life.

In Budapest, Hungary, both a city-backed movement called I Love Budapest and a special police division tackle the problem, including the provision of approved areas.

United Kingdom
The Anti-social Behaviour Act 2003 became Britain's latest anti-graffiti legislation. In August 2004, the Keep Britain Tidy campaign issued a press release calling for zero tolerance of graffiti and supporting proposals such as issuing "on the spot" fines to graffiti offenders and banning the sale of aerosol paint to anyone under the age of 16. The press release also condemned the use of graffiti images in advertising and in music videos, arguing that real-world experience of graffiti stood far removed from its often-portrayed "cool" or "edgy'" image.

To back the campaign, 123 Members of Parliament (MPs) (including then Prime Minister Tony Blair), signed a charter which stated: "Graffiti is not art, it's crime. On behalf of my constituents, I will do all I can to rid our community of this problem."

In the UK, city councils have the power to take action against the owner of any property that has been defaced under the Anti-social Behaviour Act 2003 (as amended by the Clean Neighbourhoods and Environment Act 2005) or, in certain cases, the Highways Act. This is often used against owners of property that are complacent in allowing protective boards to be defaced so long as the property is not damaged.

In July 2008, a conspiracy charge was used to convict graffitists for the first time. After a three-month police surveillance operation, nine members of the DPM crew were convicted of conspiracy to commit criminal damage costing at least £1 million. Five of them received prison sentences, ranging from eighteen months to two years. The unprecedented scale of the investigation and the severity of the sentences rekindled public debate over whether graffiti should be considered art or crime.

Some councils, like those of Stroud and Loerrach, provide approved areas in the town where graffitists can showcase their talents, including underpasses, car parks, and walls that might otherwise prove a target for the "spray and run".

Australia

In an effort to reduce vandalism, many cities in Australia have designated walls or areas exclusively for use by graffitists. One early example is the "Graffiti Tunnel" located at the Camperdown Campus of the University of Sydney, which is available for use by any student at the university to tag, advertise, poster, and paint. Advocates of this idea suggest that this discourages petty vandalism yet encourages artists to take their time and produce great art, without worry of being caught or arrested for vandalism or trespassing. Others disagree with this approach, arguing that the presence of legal graffiti walls does not demonstrably reduce illegal graffiti elsewhere. Some local government areas throughout Australia have introduced "anti-graffiti squads", who clean graffiti in the area, and such crews as BCW (Buffers Can't Win) have taken steps to keep one step ahead of local graffiti cleaners.

Many state governments have banned the sale or possession of spray paint to those under the age of 18 (age of majority). However, a number of local governments in Victoria have taken steps to recognize the cultural heritage value of some examples of graffiti, such as prominent political graffiti. Tough new graffiti laws have been introduced in Australia with fines of up to A$26,000 and two years in prison.

Melbourne is a prominent graffiti city of Australia with many of its lanes being tourist attractions, such as Hosier Lane in particular, a popular destination for photographers, wedding photography, and backdrops for corporate print advertising. The Lonely Planet travel guide cites Melbourne's street as a major attraction. All forms of graffiti, including sticker art, poster, stencil art, and wheatpasting, can be found in many places throughout the city. Prominent street art precincts include; Fitzroy, Collingwood, Northcote, Brunswick, St. Kilda, and the CBD, where stencil and sticker art is prominent. As one moves farther away from the city, mostly along suburban train lines, graffiti tags become more prominent. Many international artists such as Banksy have left their work in Melbourne and in early 2008 a perspex screen was installed to prevent a Banksy stencil art piece from being destroyed, it has survived since 2003 through the respect of local street artists avoiding posting over it, although it has recently had paint tipped over it.

New Zealand

In February 2008 Helen Clark, the New Zealand prime minister at that time, announced a government crackdown on tagging and other forms of graffiti vandalism, describing it as a destructive crime representing an invasion of public and private property. New legislation subsequently adopted included a ban on the sale of paint spray cans to persons under 18 and increases in maximum fines for the offence from NZ$200 to NZ$2,000 or extended community service. The issue of tagging become a widely debated one following an incident in Auckland during January 2008 in which a middle-aged property owner stabbed one of two teenage taggers to death and was subsequently convicted of manslaughter.

Tracker databases
Graffiti databases have increased in the past decade because they allow vandalism incidents to be fully documented against an offender and help the police and prosecution charge and prosecute offenders for multiple counts of vandalism. They also provide law enforcement the ability to rapidly search for an offender's moniker or tag in a simple, effective, and comprehensive way. These systems can also help track costs of damage to a city to help allocate an anti-graffiti budget. The theory is that when an offender is caught putting up graffiti, they are not just charged with one count of vandalism; they can be held accountable for all the other damage for which they are responsible. This has two main benefits for law enforcement. One, it sends a signal to the offenders that their vandalism is being tracked. Two, a city can seek restitution from offenders for all the damage that they have committed, not merely a single incident. These systems give law enforcement personnel real-time, street-level intelligence that allows them not only to focus on the worst graffiti offenders and their damage, but also to monitor potential gang violence that is associated with the graffiti.

Gang injunctions
Many restrictions of civil gang injunctions are designed to help address and protect the physical environment and limit graffiti. Provisions of gang injunctions include things such as restricting the possession of marker pens, spray paint cans, or other sharp objects capable of defacing private or public property; spray painting, or marking with marker pens, scratching, applying stickers, or otherwise applying graffiti on any public or private property, including, but not limited to the street, alley, residences, block walls, and fences, vehicles or any other real or personal property. Some injunctions contain wording that restricts damaging or vandalizing both public and private property, including but not limited to any vehicle, light fixture, door, fence, wall, gate, window, building, street sign, utility box, telephone box, tree, or power pole.

Hotlines and reward programs
To help address many of these issues, many local jurisdictions have set up graffiti abatement hotlines, where citizens can call in and report vandalism and have it removed. San Diego's hotline receives more than 5,000 calls per year, in addition to reporting the graffiti, callers can learn more about prevention. One of the complaints about these hotlines is the response time; there is often a lag time between a property owner calling about the graffiti and its removal. The length of delay should be a consideration for any jurisdiction planning on operating a hotline. Local jurisdictions must convince the callers that their complaint of vandalism will be a priority and cleaned off right away. If the jurisdiction does not have the resources to respond to complaints in a timely manner, the value of the hotline diminishes. Crews must be able to respond to individual service calls made to the graffiti hotline as well as focus on cleanup near schools, parks, and major intersections and transit routes to have the biggest impact. Some cities offer a reward for information leading to the arrest and prosecution of suspects for tagging or graffiti related vandalism. The amount of the reward is based on the information provided, and the action taken.

Search warrants
When police obtain search warrants in connection with a vandalism investigation, they are often seeking judicial approval to look for items such as cans of spray paint and nozzles from other kinds of aerosol sprays; etching tools, or other sharp or pointed objects, which could be used to etch or scratch glass and other hard surfaces; permanent marking pens, markers, or paint sticks; evidence of membership or affiliation with any gang or tagging crew; paraphernalia including any reference to "(tagger's name)"; any drawings, writing, objects, or graffiti depicting taggers' names, initials, logos, monikers, slogans, or any mention of tagging crew membership; and any newspaper clippings relating to graffiti crime.

Documentaries

 * 80 Blocks from Tiffany's (1979), a rare glimpse of the late 1970s in New York City toward the end of the notorious South Bronx gangs, the documentary shows many aspects of the South Bronx's predominantly Puerto Rican community, including reformed gang members, current gang members, the police, and the community leaders who try to reach out to them.
 * Stations of the Elevated (1980), the earliest documentary about subway graffiti in New York City, with music by Charles Mingus
 * Style Wars (1983), an early documentary on hip hop culture, made in New York City
 * Piece by Piece (2005), a feature-length documentary on the history of San Francisco graffiti from the early 1980s
 * Infamy (2005), a feature-length documentary about graffiti culture as told through the experiences of six well-known graffiti writers and a graffiti buffer
 * NEXT: A Primer on Urban Painting (2005), a documentary about global graffiti culture
 * RASH (2005), a feature documentary about Melbourne, Australia, and the artists who make it a living host for street art
 * Jisoe (2007), a glimpse into the life of a Melbourne, Australia, graffiti writer shows the audience an example of graffiti in struggling Melbourne Areas.
 * Roadsworth: Crossing the Line (2009), about Montréal artist Peter Gibson and his controversial stencil art on public roads
 * Exit Through The Gift Shop (2010) was produced by the notorious artist Banksy. It tells the story of Thierry Guetta, a French immigrant in Los Angeles, and his obsession with street art; Shepard Fairey and Invader, whom Guetta discovers is his cousin, are also in the film.
 * Still on and non the wiser (2011) is a ninety-minute-long documentation that accompanies the exhibition with the same name in the Kunsthalle Barmen of the Von der Heydt-Museum in Wuppertal (Germany). It draws vivid portrayals of the artists by means of very personal interviews and also catches the creation process of the works before the exhibition was opened.
 * Graffiti Wars (2011), a documentary detailing King Robbo's feud with Banksy as well as the authorities' differing attitude towards graffiti and street art

Dramas

 * Wild Style (1983), about hip hop and graffiti culture in New York City
 * Turk 182 (1985), about graffiti as political activism
 * Bomb the System (2002), about a crew of graffitists in modern-day New York City
 * Quality of Life (2004) was shot in the Mission District of San Francisco, co-written by and starring a retired graffiti writer.
 * Wholetrain (2006), a German film

title: Graffiti