Urban Agriculture Technology
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Urban Agriculture Technology

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Urban Agriculture Technology

Urban Agriculture Technology

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Urban Agriculture Technology Urban Agriculture Technology Document Transcript

  • URBAN AGRICULTURE TECHNOLOGY This document presents topics relevant to urban agriculture technologies. The topics are:  Green houses & food treatment  Green roofs  Vertical gardens  Urban livestock  Hydroponics 1. Green houses & food treatment Definition: A building, room, or area, usually chiefly of glass, in which the temperature is maintained within a desired range, used for cultivating tender plants or growing plants out of season. Origin: Greenhouses evolved from Orangeries – a structure developed for nobility some 300 years ago, “partly because of fashion, and partly because weather seemed to be colder than it had been in previous centuries.” An Orangerie, much like a greenhouse were constructed to create a warm space that could create a ‘summer’ environment and where the nobility could entertain during the colder months. Moreover, projects like Kew Gardens demonstrate a desire for human desire for worldliness. Residents of a colder climate wished to possess the beauties of warmer nations. By 1824, the popularity of greenhouses was gaining momentum all across Europe, no longer reserved for the highest elite, they were being used more and more for horticulture purposes. Greenhouses in Québec: The Conseil de production végétale du Québec states that a greenhouse must be able to support its own weight, as well as that of any covering, wind load, snow load, and the produce load without significantly interfering with light. As well, it must be efficient in heating and ventilation, while allowing a sufficient amount of space for cultivating and the work involved. Moreover, it must be agreeable in appearance and be as cost efficient as possible. There are two principal kinds of greenhouses – the traditional greenhouse and the ‘hoop house’. Where the hoop house acts more as protection and thus requires minimal heating and ventilation systems to minimally maintain environmental parameters to slightly prolong the growing season (late March to October), the traditional greenhouse’s goal is more to cultivate in all seasons through optimal control of climatic conditions, which must be more precise. For the emplacement of a traditional greenhouse, in a rural setting, one must consider many factors – these considerations don’t differ too much in an urban setting. The topography must be more or less flat, no more than a 1% slope, the area must be large enough to house the greenhouse, the connected buildings and storage. There are two significant factors that should dictate the orientation of the greenhouse – the wind and the light. Winds have less significant impact on a greenhouse that is orientated in the same direction as the dominant winds, this eases the mechanical ventilation of the greenhouse. In Québec, most of the dominant winds blow from West to East, however, at times, larger structures (especially in an urban setting), can affect their direction, thus these should be investigated. East-West greenhouses benefit from more significant light in the winter months, however, this light is less consistent in other months than a North-South orientated greenhouse. Still, if the goal is a year- round production, it is preferable to orient the greenhouse on an East-West axis ± 15º. It would not be preferable to build a greenhouse in an urban context, as, for lighting purposes, a greenhouse should be distanced by 2.5 times the height of an obstacle. Also, in order to avoid
  • accumulation of snow, it is preferable that a greenhouse be at least 30 m away from obstacles. Elevating a greenhouse would do a lot to rectify these issues, allow for construction in a more urban setting. To avoid inundation, facilitating the evacuation of water should also be important. For more information on the actual structure of a greenhouse for a Québec climate, please refer to Serre: Construction et aménagement pages 20 to 30. For more information on the most preferable equipment for year-long production in our climate, refer to pages 31 to 70. Most preferable species: Because of the constraint environment that is a greenhouse, small compact plants are most preferable, especially in an urban setting where there is not much room for the implementation of many structures. From an economic perspective, should we wish to yield a profit from a greenhouse, the most cost effective vegetables would be cucumbers, tomatoes, peppers and strawberries, as they do not require much room and do give a significant yield. However, is profit is not the goal, but rather the greenhouse is to be an aspect of Community Sustained Agriculture (a project that may or may not be started through government funding, but that is managed by the community), the crop could be expanded to include bok choi, cabbage, lettuce, snap peas, radishes and beets, onions, broccoli. Berry shrubs are also feasible. Fresh herbs are most likely the easiest plant. Vine plants as well as root vegetables are not preferable for an urban greenhouse environment. Weather effects (salt and cold): In climates like Montreal, the roads are heavily salted in winter. The spray from streets on plants can be very damaging if the plants are sensitive to salt. The leaf buds may stop opening, and road-facing sides may die altogether. Luckily, there are plants that are more tolerant of salt. There are many trees, vegetable, and vines that will all survive outside in salty environments – notably vines like grapes and honeysuckle will. The table below is an example of vegetables and their salt tolerances. Table 1. Relative salt tolerance of vegetables* High salt tolerance Medium salt tolerance Low salt tolerance 12 mmhos 10 mmhos 4 mmhos beet tomato radish kale broccoli celery asparagus cabbage bean spinach pepper cauliflower lettuce corn potato muskmelon carrot onion pea squash cucumber 10 mmhos 4 mmhos 3 mmhos
  • * Relative salt tolerance decreases down each column, e.g., tomato is more salt tolerant than cucumber. Another factor of Montreal weather is the cold. There are plants that are especially hearty in cold weather and will not be killed by a frost. The best are beets, Brussels sprouts, carrots, collards, kale, parsley, and spinach. For more information on what vegetables will survive best in our climate, check out the attached links. Native Species: Many of the vegetables we eat may not be local, but the First Nations people fed themselves off the land for years. Plants such as wild greens, seaweed, roots and bulbs, and berries have been grown naturally in Canada. Heating alternatives info: Greenhouses in temperatures like Montreal require alternate forms of heat in the winter months as the sun is more often than not, not enough. To make them more economic and use less energy from fossil fuels and other non-renewable resources, methods used to heat homes can be applied to greenhouses as well. For example, solar heat, bio-diesel, and wind power can be used to heat greenhouses. Compost heat can be harnessed by attaching a compost to a greenhouse. This also increases the CO2 levels for better plant growth, something that is normally done by machines. For greenhouses on rooftops, the escaping heat from air-conditioning and heating units can be transferred over to heat the greenhouse fairly simply. The Science Barge: The Science barge is the pet project of scientists and engineers from the New York Sun Works, a non- profit organization. They implemented, in the Hudson River Harbour, “a sustainable urban farm powered by solar, wind, and biofuels, and irrigated by rainwater and purified river water.” The vegetables production produces no carbon emissions, no net water consumption and no waste stream. The vegetables also require seven times less land and four times less water than regular rural farming processes. At this time, it is one the most innovative and successful example of urban agriculture for a climate similar to that of Québec. For more information on the Science Barge, http://www.nysunworks.org/?page_id=9 New York Sun Works is also playing an important role in Building Integrated Agriculture and Controlled Environment Agriculture. You can check out their website: http://www.nysunworks.org Container Growing: Since 1990, container growing, mostly in what is called pépinières (greenhouse-like structures), has been rapidly gaining popularity in Québec. Traditionally, container growing is defined as cultivating plans in a pot, outside the soil, during a gestation period and until the definitive planting by the user. The plant must spend at least one gestation period in this pot, that its roots might spread and utilise the whole container so it becomes easier to transfer, later, into soil. However, as McGill’s Edible Landscapes project has demonstrated (http://www.mcgill.ca/mchg/pastproject/el/), it is entirely feasible in an outdoor urban area, to produce plants for consumption in one growing season as a Community Sustained Agriculture project. Before undertaking such a project, one must be conscious of the availability of water, wind protection, topography, cost of terrain, availability of labour, and distance from markets and services (if it is to be economically viable). In Québec, we can expect to be able to keep growing containers outside from about end of May to early October. Therefore there must be buildings available to keep the plants during the winter months. For more detailed information on the specifics of container growing, the Conseil des productions végétales du Québec’s books Pépinière: Culture en Containeurs – Planifications, Pépinière: Culture en Containeurs – Hivernage, and Pépinière: Culture en Containeurs – Irrigation provides excellent step by step information on the process. View slide
  • Biotop Canada (www.biotopcanada.com) Composting: Composting has a variety of methods, for small spaces, indoor spaces, and urban spaces. Basic city composting is done in bins with tight fitting lids and bases and no openings large enough for animals, to keep pets away. The containers can be made of metal, plastic, or reinforced wood. The first step of composting is to add 3-4” of woody material to get air to the bottom of the pile, not to be mixed in. Add 2-4” layers of green and brown materials alternately, until the bin is full. Green material is classified as nitrogen products, such as grass or food scraps. Brown material is carbon material, like leaves, newspaper strips. Add a thin soil layer whenever adding a green layer to the top, to prevent smell and animals. Mix bin at least every two weeks, combining old and new materials and adding air for faster decomposition. Continue until bin is full, cover with carpet to retain heat and moisture. Compost will be ready after 2-3 months, but letting is sit for another month or two is suggested. Worm Composting: Worm composting is an easy indoor alternative. It can be done indoors or out, and in small buckets, so is great for apartments all year round. Just add moistened bedding and worms to container, and let sit. Add your food waste and over time it will become rich soil. Rainwater Collection: Rainwater can be collected with very little extra effort. After being channelled through downspouts and eaves troughs, it can be collected in large cisterns and used when needed. A roof can collect up to 0.62 gallons/square foot of roof footprint/inch of rain. Rainwater can also be used after treatment for potable uses. A concrete cistern can filter the water to meet national standards. The water is filtered through sand, treated by activated carbon adsorption, and disinfected by an ultraviolet treatment unit before being stored in a large storage tank. Before being pumped into fixtures the water is disinfected again. Urban Orchards: With limited space in urban environments, fruit trees often take up too much space to be feasible. Espalier is a technique that has been used for centuries, to grow fruit trees in 2 dimensional planes. The ability to grow trees against walls not only saves space but can create more fruitful trees. Most trees grown in this manner are grown with grafted dwarf root stock, so that the trees are smaller, although the fruit remains the same. This means that pruning and fruit collection are easier. Planting against walls can extend the plants’ growing season. Because the growing wall will both reflect and absorb heat, the plant is exposed to heat longer than a freestanding tree. Another advantage of espaliering is that more of the plant is exposed to direct sunlight. This results in more flowering and more fruit. The best varieties to try this with are apple or pear trees, but it is possible with fruits such as plums or cherries. The best locations to grow are along faces that receive direct sunlight in the summer but are protected in the winter. And east facing wall will work for this. The process requires care but is relatively simple. Heavy wire is strung up at 0.5 to 1.0 meter intervals, and the branches are trained to grow along these. The trellises can be freestanding or connected to buildings. The diagram below illustrates the steps of creating an espalier. View slide
  • Relevant Sources: For greenhouse construction : Conseil des productions végétales du Québec. Serres : Construction et aménagement. Gouvernment du Québec, 1994. Kurth, Heinz and Geneste. Greenhouses for Longer Summers. Prentice-Hall Canada Inc, Scarborough, Ontario. 1982. Northeast Regional Agricultural Engineering Service. Greenhouse Systems – Automation, Culture and Environment. Cooperative Extension, Ithica, New York, 1994. Northeast Regional Agricultural Engineering Service. Greenhouse Engineering. Cooperative Extension, Ithica, New York, 1994. Agriculture Canada. Energy-conserving urban greenhouses for Canada. Ministry of Supply and Services Canada, 1987. Health and Welfare Canada. Native Foods and Nutrition. Ministry of Supply and Services Canada, 1985. For container growing : Conseil des productions végétales du Québec. Pépinière : Culture en conteneurs – planification. Gouvernement du Québec, 1993. Conseil des productions végétales du Québec. Pépinière : Culture en conteneurs – irrigation. Gouvernement du Québec, 1993. Conseil des productions végétales du Québec. Pépinière : Culture en conteneurs – hivernage. Gouvernement du Québec, 1993.
  • 2. Green Roofs Definition: ”A green roof is a green space created by adding layers of growing medium and plants on top of a traditional roofing system. This should not be confused with the traditional roof garden, where planting is done in freestanding containers and planters, located on an accessible roof terrace or deck.” A green roof system has several layers, which include, from the top to bottom: • “The plants, often specially selected for particular applications, • An engineered growing medium, which may not include soil, • A landscape or filter cloth to contain the roots and the growing medium, while allowing for water penetration, • A specialized drainage layer, sometimes with built-in water reservoirs, • The waterproofing / roofing membrane, with an integral root repellent, and • The roof structure, with traditional insulation either above or below.” Source: http://sitemaker.umich.edu/section9group1/files/greenroof1.jpg ”Green roofs can be designed to be an integral part of a new building, or can be installed later on an existing building. When a building is designed with a green roof system, there can be several benefits. For example, the building is designed to provide the necessary structural support, and won't require reinforcement later. Also, the building can be designed to take advantage of the aesthetic value that a green roof can offer by providing viewing areas.” Brief History: Green roofs have been an integral part of construction systems throughout the world, in both cold and warm climates, at both large and small scales. Earlier examples include the hanging gardens of Babylon which consisted of 3 acres, spread out over seven stories spanning 75 feet vertically. In Scandinavia, the roofs of wooden houses were garnished with sod to insulate them from the cold during wintertime.
  • Source: http://blogs.smh.com.au/lifestyle/renovationnation/swedishgrassroof.jpg In the 20 th century, Le Corbusier experimented with green terraces, and the designs of the Rockefeller Center in New York and the Union Square in San Francisco both incorporated green roofs. The green roof industry has recently taken off with the introduction of more efficient building materials, especially when it comes to insulating membranes, as well as a growing environmental consciousness since the 1960s. Currently, the green roof industry is ahead in Europe, in contrast to North America. In Germany, the demand for green roof technology grew significantly in the 1980s. The government presented incentives to the public, such as paying households 35 to 40 Deutsche Mark per square meter of the roof area, which was converted to accommodating greenery. Types: There are several categories of green roofs, and it is important to distinguish them. There are complete systems, modular systems and pre-cultivated vegetation blankets. Complete systems “In a complete green roof system, all parts of the roof are designed to support vegetation growth. These systems provide the most flexibility in terms of the type and nature of growing medium, drainage and protection layers and type of vegetation. Complete systems vary in thickness and weight from as low as 50mm to 75mm (2 to 3 inches) in depth and 60 to 90 kg per sq. m, (12 to 18 lbs per sq. ft.) in weight. They can be installed with a variety of waterproofing membrane types.” Complete systems break up in two important categories, the intensive and extensive green roofs. Table 1 outlines the differences between these two systems.
  • Source: Design Guidelines for Green Roofs, p. 7 The following schema portrays the differences between the intensive and extensive roof types. Source: Architectural Record 03.03, p. 150
  • Modular systems “Modular systems are essentially trays of vegetation in a growing medium that are grown off- site and simply placed on the roof to achieve complete coverage. They are available in different depths of growing medium typically ranging from 75mm to 300mm (3 to 12 inches). The variety of vegetation is typically more limited.” Source: http://www.toronto.ca/greenroofs/images/greengrid385_289.gif Emerging technologies focus on modular systems, seeing that the implementation is easy and requires less effort than the complete green roof system. An example of such a technology is the Biotop System. Especially designed containers permit plants to develop two sets of root system, permitting plants to grow to full maturity without transplanting them. More information is available at http://www.biotopcanada.com. Pre-cultivated vegetation blanket “A pre-cultivated vegetation blanket is a pre-grown interlocking green roof tile. The blanket shown below is available in a thickness of about 45mm (1.75 inches). Blanket systems are available in a variety of system designs. The most versatile system contains 25 mm (1 inch) of planting substrate. The result is a lightweight system ranging in weight from 40 to 60 kg per sq. meter. The majority of the vegetation is made up of several varieties of Sedum, a succulent plant (8.0 to 13.0lbs per sq. ft.) tolerant to extremes in temperature that survives with little or no irrigation while requiring very little maintenance. They are cultivated at ground level, then rolled and transported as a complete system on pallets or by crane.” Source: http://www.toronto.ca/greenroofs/images/elt191_156.gif
  • Benefits: There are many benefits to having a green roof. All sources point these out unanimously. For a building owner, a green roof can present the following benefits:  Energy savings: The green roof protects the building from direct solar radiation, and helps prevent inside temperature from rising. This in turn lowers the energy bill required for cooling the building. In the winter, the added cover and insulating membranes needed in the roof installation help conserve heat.  Roof membrane protection and life extension: The presence of a green roof may double the lifespan of the roof by protecting it against large fluctuations in temperature, UV rays and pedestrians.  Sound insulation: The growing medium helps block lower frequencies of sound, while the vegetation blocks part of the higher frequencies. This could be applicable to noisy residential areas, such as near airports.  Fire resistance: Some studies show that green roofs slow down the spread of fire, since the growing medium is wet or humid.  Additional usable space: Green roofs permit to creation of additional recreational areas or retreats for the elderly or patients in hospitals.  Urban agriculture: The roofs permit the production of “high quality organic foods, and medicinal and ornamental plants. This has the advantage of reducing associated transportation and refrigeration costs, reducing the time and distance from field to table, ensuring ripeness at harvest, and providing new employment opportunities for city dwellers.” This is clearly the case in McGill’s Edible Landscape Project. Green roofs also profit the general public in several ways.  Urban heat island effect: Urban and suburban areas tend to overheat in the summer because of the important presence of dark, asphalt-paved surfaces, which absorb heat. This leads to an over-consumption of energy to cool down habitable areas. Green roofs permit to absord or reflect the solar rays and reduce the temperature in cities.  Storm water retention: This aspect is particularly relevant to Montreal. When it rains, the water is collected in the city’s sewage system. In Montreal, during excess water accumulation, the sewage system releases the water into the St. Lawrence and Des Prairies Rivers – which obviously has environmental consequences. Green roofs permit to accumulate some of the water, or at least prevent it from going directly into the sewage system. Additionally, the rain water is filtered by the green roof, so the runoff is cleaner.  Air cleaning: Not only do green roofs permit additional conversion of CO2 to O2, but the plants also capture airborne polluting particles.  Creation of habitat: Green roofs can accommodate specifies of plants and animals, such as birds and insects, that
  • would otherwise lack shelter or a habitable space. Other Considerations: See pages 10-18 in the Design Guidelines for Green Roofs, at http://www.cmhc- schl.gc.ca/en/inpr/bude/himu/coedar/upload/Design-Guidelines-for-Green-Roofs.pdf for a complete breakdown of variables to consider when building a green roof, such as maintenance, laws and cost estimates. Examples: An extensive list of green roofs is available at the following website: http://www.greenroofs.com/projects/plist.php References: The following site is the most comprehensive source, especially for this project. Although many sources were consulted, the following one really proved to be the most complete and adapted for understanding the basics of green roofs. http://www.cmhc-schl.gc.ca/en/inpr/bude/himu/coedar/upload/Design-Guidelines-for-Green-Roofs.pdf Similar information (almost identical) was also found in the following book, published in French. It is an especially good source for local Montreal projects and discussing local laws when it comes to green roofs. ”Toitures vertes à la montréalaise”, by Maude Landrevile, available at the Blackadder-Lauterman library. Two other sites proved to be good, and have more links to yet other useful pages. http://www.toronto.ca/greenroofs/what.htm http://www.bluestem.ca/green-roofs.htm
  • 3. Vertical Gardens At the turn of the twentieth century, Gertrude Jekyll, inspired by the Arts and Crafts Movement in Great Britain, starts planting vegetation in the cracks and crevices of stone walls. Almost one hundred years later, Patrick Blanc, the pioneer behind the modern vertical garden creates hydroponic living walls after observing how vegetation can grow on soilless surfaces (cliff sides, rocks, tree trunks) in Malaysia. His vertical gardens can turn the banal wall of a city into “a valuable shelter for biodiversity.” Patrick Blanc’s Mur Vegetal manage to weave very natural ecosystems into the urban fabric in a very dynamic and innovative manner. www.verticalgardenpatrickblanc.com
  • Patrick Blanc’s vertical gardens were the catalyst for a new form of horticulture and gardening. A great example of this is ELT Living Wall Systems, who are based out of Brantford, Ontario. ELT began as a company that manufactured easy-to-assemble green roof tiles, and now they also provide modular living wall panels for both pre-grown and planted vegetation—all you need is soil and your plant of choice. The vertical garden tile is made in way that will retain soil, but allow for the even distribution of water and nutrients. The pockets slope downwards and have grooves that will push the
  • water to the back so that the roots can get the necessary food and stay moist. Water is poured into the panel from the top and then trickles down to the bottom where excess water is caught in a catch- basin. The ELT living wall panels can be used to grow anything from ornamental grasses to flowers to vegetables and herbs and can be arranged to created very interesting textures and patterns. The panels are made of UV resistant 100% Recyclable black High Density Polyethylene. www.eltlivingwalls.com The MFO park in Zurich Switzerland is an exemplifying project that uses the notion of gardening vertically. Burckhardt + Partner and Raderscall Landschafts architekten designed what has been dubbed an “urban park”, where a lightweight metallic lattice structure has been built for the growth of vines. Visitors access the structure via stairs, reaching a sundeck, loggias, and cantilevered lookouts that give an overhead glimpse of the space below. At this lowest level are benches, pools, and the start of the vines following cables that taper outwards in a conical shape towards the roof. Depending on the time of year one visits, the vegetal "walls" are sparse, full, or colorful. http://www.raderschall.ch/projekte/parks/mfo1.php
  • 4. Urban Livestock Potentially positive and/or negative aspects of animal keeping: Positive (or negative) Negative (or positive) - produce (healthy) food - dung and urine disposal problems - use waste / clean or scavenge the environment - disease risk - provide income and emotional value - theft - status, savings, tradition - zoonoses / hygiene - dung for garden - nuisance - draught - much work René van Veehuizen, ed., Cities Farming For the Future. RUAF Foundation, 2006. Opportunities and Barriers to Urban Livestock Keeping in the North America: Barriers * Little known, unknown, and/or illegal experience on which no information is available * Disparate and un-coordinated legal codes at municipal level on urban livestock keeping * Space restrictions * Inadequate knowledge and/or unsafe (eg. unsanitary) practices * Cultural resistance to raising animals for food and other economic purposes * Often practised by marginalised groups and regulated by elite groups. Opportunities * Survives because of economic need, cultural endurance, and social resistance * Produces fresher and tastier meat * Experiences brought by immigrant and rural migrant communities * Local dialogue between practitioners and regulators can proceed in tandem with new development at international level * Species for small areas like fish, guinea pigs, rabbits, and chickens incomplete * Technical training; workshops; community engagement in urban livestock * Community-wide food systems education * Community dialogue on food security needs René van Veehuizen, ed., Cities Farming For the Future. RUAF Foundation, 2006. Feasible Animals for The City: Aquaponics:
  •  Aquaponics is a system where fish and plants are raised in the same system. (see the Growing Power section under Precedents for an explanation of how a system would work)  Talapia-Relatively adaptable, although they prefer warm water. They eat algae, salad, and worms. They are easy to raise, and marketable to restaurants.  Yellow Perch-They are bottom feeders, and will therefore eat almost anything. They prefer cooler water and are a favorite among chefs.  A simple re-circulation system can be as small as 4ft x 4ft. (see http://www.webofcreation.org/BuildingGrounds/aqua/TOC.html for information on how to build one) and can sustain 20-30 tilapia fingerlings. Vermiculture:  Worm (red wigglers) compost; a nutrient rich, organic fertilizer and soil conditioner.  Produces compost with a higher nutrient ratio than any other composting method.  Worm castings are rich with microbial life which aids in breaking down nutrients already in the soil into a form that plant roots can absorb.  Worm mucus helps soil hold moisture better and keeps nutrients from washing away.  Worms can be raised in bins or piles of soil, and therefore require minimum overhead and maintenance.  Worms eat food waste (twice their body weight/day) and multiply rapidly.  Requires little room.  See http://www.growingpower.org/worms.htm for more information. Honeybees:  One hive contains appx. 60,000 bees and produces appx. 150 lbs. honey/year.  Requires little room.  Helps produce bigger fruit and vegetables. Chickens:  Require appx. 4 sq. ft./chicken  One chicken lays appx. one egg every 25 hrs.  Improves garden health  Suppresses pests and weeds  Builds soil fertility  Produces much fresher eggs than are sold at the regular supermarket Goats:  Require 60 sq. ft./goat  Requires appx. 20 minutes of care per day  Can be used for dairy (milk, butter, yogurt, cheese) or sold for their meat to ethnic groups.  Eat leftover vegetable waste  See http://www.goselfsufficient.co.uk/keeping-a-goat.html for more information. Precedents:  Fairmont Hotels: -The Fairmont Royal York, Toronto, Ontario -3 queen bees and 10,000 worker bees are residing in the 14 th story triple hive apiary. -Executive chef David Garcelon in partnership with Toronto Beekeepers’ Cooperative and Foodshare will deliver local sustainable honey to hotel guests. -The bees are a natural extension of the existing roof-top herb garden. -They encourage more flowers, healthier plants and bigger fruit. -See http://radioroyalyork.ca/2008/06/the-fairmont-royal-yorkencourages-urban-bee-havior/ for more information.
  • -The Fairmont Waterfront, Vancouver, BC -2 queen bees and 120,000 worker bees are residing in the “Honey Bee Suites” which are adjacent to the 2,100 square foot herb garden located on the third-floor terrace. -The honey is used in the hotel’s food dishes as well as in its bar where it is incorporated in their martini recipes. -See http://www.edible-britishcolumbia.com/blog/?cat=8 for more information.  Growing Power, Milwaukee, WI: -Non-profit Urban Agriculture and Education Facility -Grows enough food for 2,000 people on 2 acres -Raises tilapia, yellow perch, worms, bees, chickens, goats, ducks, and turkeys. -Aquaponics system: -Tilapia and yellow perch are raised in tanks whose water is drained into a gravel bed where watercress and bacteria break down the ammonia into nitrogen. The water is pumped to the growing beds and then back to the fish tank. The system is easy to build and only requires a small pump and heat to run. -See http://www.growingpower.org/ for more information.  Some Relevant Heifer International Projects http://www.heifer.org -The Toronto Beekeepers Cooperative -3 hives were given to The Toronto Beekeepers Cooperative and Foodshare in 2002; they are currently keeping 12 hives with a few hundred thousand bees -They passed on 3 hives to the Everdale Environmental Learning Centre in 2003 to “pass on the gift.” -The bees contribute to more productive urban fruit and vegetable harvests as pollinators are not abundant in cities. -This provides a local source of sugar, reducing the demand for imported sugar cane whose production is responsible for more biodiversity loss than any other crop worldwide. -For most people in the city, this is the only accessible way to learn beekeeping. -Healing bee products, creams, salves, lip balm, honey-wine and candles are also produced. -See http://www.foodshare.net/download/Urbanbees.pdf for more information. -Just Food’s City Farms Program, New York City -Teaches low-income neighborhoods how to grow their own produce and livestock and then allows them to sell it for profit at City Farms Markets. -Have recently developed a City Chicken program which promotes the best practices of raising chickens in the city and teaches people how to build coops and city regulations. -See http://www.justfood.org/cityfarms/chickens/ for more information. -ReVision House Urban Agriculture, Dorchester, MA -Provides job training, transitional housing and education to homeless young mothers and their children. -Market-based urban farming program -Aquaponic system produces tilapia and herbs. The three story back porch of the reVision house was converted into a solar greenhouse where hydoponic systems were constructed. -Apiculture (honey bees) -Vermiculture -See http://www.vpi.org/Re-VisionFarm/ for more information. -Cabrini Greens Project, Chicago, IL -Kids from the Cabrini Greens housing project grow produce and raise chickens, goats, and ducks -Currently raising the funds to buy a pasteurizing machine so that cheese can be made from the goats’ milk. -Expecting two bull calves to plow their land. -See http://www.growingpower.org/chicago_projects.htm and http://www.metropolismag.com/html/content_1098/oc98risk.htm for more information
  • 5. Hydroponics WHAT IS HYDROPONICS? Hydroponics is a method of growing plants by using a water and nutrient solution instead of soil. The term is derived from the greek word ‘hydro’ meaning water and ‘ponos’ meaning labor. Almost any plant will grow using hydroponics, but there are some that are more practical and take to it better than others. Examples of such plants are fruit bearing crops, leafy crops such as lettuce, herbs and flowering plants. “The hydroponic greenhouse vegetable industry has a growth rate of 10 percent per year and accounts for nearly 95 percent of the greenhouse vegetables produced in North America.” http://www.buzzle.com/articles/hydroponics-in-commercial-food-production.html BENEFITS OF HYDROPONICS IN URBAN AGRICULTURE -More plants can be grown in a given space -Less water used since none is consumed by weeds (5% of the water soil would use!) -Plants can be stacked vertically -No runoff -No soil born disease -Grow year round -More control over nutrient levels equals better produce -Plants need different amounts of water depending on what stages of growth they’re in -Combine raising fish with hydroponics by attaching a fish tank to the system and instead of having to clean the fish tank the waste can be cycled through the system and used as plant food. WHAT IS NEEDED? 1. The Growing Medium -used mainly for starting seedlings -the less amount used the better in terms of cost -ideally reuseable or biodegradable -porous, clean, no effect to pH balance, drainable -aims to hold an equal amount of air and water -ex: vermiculite sawdust, peat moss, sand, perlite (air puffed glass pellets), rockwool (molten rock spun fibers) coconut coir (from coconut husks) perfect starts (molded sponge made from organic compost and a biodegradable binder) 2. Nutrients In soil nutrients come from rocks, minerals, animal waste, and decomposing plants and animal matter. Soil provides a buffer to the plants, so in hydroponics if something is wrong with the solution the plants will be effected instantly. 3. Oxygen -Roots need air! -Roots absorb oxygen and in turn emit carbon dioxide. -It is important the roots receive air to maintain health and avoid rotting as well. HOW IS IT DONE? There are many different hydroponic techniques. NFT system
  • -no medium -plants suspended in channel of solution -solution flows through one end of the tray and back into the reservoir through the other -roots not completely submerged but only at the bottom -requires a pump -a power outage will kill most of the plants and is a large drawback Wick System -nutrient solution drawn into a growing tray holding a medium from a larger reservoir by a wick Water Culture System -floating styrofoam platform holds plants -air pump supplies oxygen to roots of plants, which are kept in the solution -mainly good for growing lettuce -cheap Ebb and Flow System -flooding and draining the growing tray by pump connected to a timer -solution cycles from the trays to the reservoir -flooding and draining can be set specific to the plant type and time of day -similar power outage drawback Drip System -nutrient solution is dripped onto plants from a reservoir containing a submerged pump -in a recovery drip system excess solution returns to the reservoir -a non recovery drip system requires less attention because the nature of the solution isn’t changed each time it is collected from the plants Aeroponics System -roots hang in the air and are misted with the nutrient solution Current Hydroponic Development http://www.youtube.com/watch?v=CCTOR6m3k9w “we’ve stacked up people but we have not stacked up farming” Sources: www.hydroponicsdictionary.com www.omegagarden.com Related Considerations: Water Quality “In selecting a greenhouse site, a grower must be aware of several chemical properties that might cause problems for greenhouse growers: pH, alkalinity, soluble salts, calcium, magnesium, boron, fluoride, chloride, sulfates, sodium, carbonate, and iron. The cleaner the water, the greater the opportunity to achieve maximum yields. The water designated for use in a greenhouse must be analyzed for agricultural suitability during greenhouse site selection.” Greenhouse environment “Computers can operate hundreds of devices within a greenhouse (vents, heaters, fans, hot water mixing valves, irrigation valves, curtains. lights. etc.) by utilizing dozens of input parameters, such as outside and inside temperatures, humidity, outside wind direction and velocity, carbon dioxide levels and even the time of day or night. Unlike early control systems, computers are used today to collect and log data provided by greenhouse production managers. A computer can keep track of all relevant information. such as temperature, humidity, C02, and light levels. It dates and time tags the information and stores it for current or later use. Such a data acquisition system enables the grower to gain a comprehensive understanding of all factors affecting the quality and timeliness of the product. Whatever the source of energy, it should be conserved once it is in the greenhouse. In regions of cold winter weather, thermal curtains of porous polyester or an aluminum foil fabric are
  • installed to reduce night heat loss by as much as 57%. In the deserts of the southwest, winter temperatures are not severe enough to warrant curtains. While curtains will provide energy savings, they are not sufficiently effective to warrant their high cost. Furthermore, the shade from the curtains, even when rolled up and stored during the day, can reduce yields.” http://ag.arizona.edu/PLS/faculty/MERLE.html Merle H. Jensen Department of Plant Sciences, University of Arizona, Tucson, AZ 85721 Lighting One of the key advantages of hydroponics is the level of control over plant needs. Control over the amount of light is often reached using grow lights, since hydroponic systems are ideal for growth indoors. “Metal halide grow lights consist of an arc tube made of alumina, inside of which is argon, mercury vapor and a variety of metals. The different metals give color to the light the lamp produces. The argon gas is used to get the lamp going at first when electrical current is introduced inside the arc tube from electrodes on either end. The arc of current vaporizes the metals and mercury, and thus light is produced. The benefit of using these lamps is that for such small bulbs they produce a lot of light, and are efficient to run. HPS grow lights are also called high-pressure sodium lights. Like the MH lights, HPS lights also use an alumina arc tube. Inside this tube you will find sodium, mercury, and the noble gas Xenon to get the light started. Like the metal halide lights, HPS lights also require a ballast for their use, to stabilize their operation. LED grow lights are similar in function to the lights you might see on Christmas trees during holiday times. They are a small, efficient and very bright light. The diode functions as a semi-conductor, and there are two crystals in this type of bulb. LED bulbs light up when electrical current moves from one crystal to the other. The light produced is surrounded by a reflector and is used with a lens to emit the light where you want it to go.” http://EzineArticles.com/?expert=Susan_Slobac