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[[Image:Worm.casts.jpg|thumb|right|Rotary screen harvested vermicompost, composed of worm castings]] |
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'''Vermicompost''' is the product or process of [[composting]] using various [[worm]]s, usually [[Eisenia foetida|red wigglers]], [[Enchytraeus buchholzi|white worms]], and other [[earthworm]]s to create a [[heterogeneous]] mixture of decomposing vegetable or food waste, bedding materials, and vermicast. Vermicast, also called worm castings, worm humus or worm manure, is the end-product of the breakdown of [[organic matter]] by an [[earthworm]].<ref name=autogenerated1>{{cite web |url=http://southwoodsforestgardens.blogspot.com/2009/01/paper-on-invasive-european-worms.html |title=Paper on Invasive European Worms |accessdate=2009-02-22}}</ref> These castings have been shown to contain reduced levels of contaminants and a higher saturation of nutrients than do organic materials before vermicomposting.<ref name="Effects of stocking density and feeding rate on vermicomposting of biosolids">{{cite journal | author = Ndegwa, P.M.; Thompson, S.A.; Das, K.C. | title = Effects of stocking density and feeding rate on vermicomposting of biosolids | journal = Bioresource Technology | volume = 71 | issue = | pages = 5–12 | year = 1998 | pmid = | doi =10.1016/S0960-8524(99)00055-3 | url = http://www.earthworm.co.za/wp-content/uploads/2009/04/effect-of-stocking-density-feeding-rate-on-vermicomposting-of-biosolids.pdf }}</ref> |
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Containing water-soluble nutrients, vermicompost is an excellent, nutrient-rich [[organic fertilizer]] and soil conditioner.<ref>Coyne, Kelly and Erik Knutzen. ''The Urban Homestead: Your Guide to Self-Sufficient Living in the Heart of the City.'' Port Townsend: Process Self Reliance Series, 2008.</ref> This process of producing vermicompost is called ''vermicomposting''. |
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==Suitable species== |
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One of the [[earthworm]] species most often used for composting is the Red Wiggler (''[[Eisenia fetida]]'' or ''[[Eisenia andrei]]''); ''[[Lumbricus rubellus]]'' (a.k.a. red earthworm or dilong (China)) is another breed of [[worm]] that can be used, but it does not adapt as well to the shallow [[compost]] bin as does ''Eisenia fetida''. European nightcrawlers (''[[Eisenia hortensis]]'') may also be used. Users refer to European nightcrawlers by a variety of other names, including dendrobaenas, dendras, and Belgian nightcrawlers. African Nightcrawlers (''[[Eudrilus eugeniae]]'') are another set of popular composters. ''[[Lumbricus terrestris]]'' (a.k.a. Canadian nightcrawlers (US) or common earthworm (UK)) are not recommended, as they burrow deeper than most compost bins can accommodate.<ref name="thf">{{cite web | url=http://herronfarms.webs.com/blog/ | title=Composting with earthworms| publisher=Herron Farms Dawsonville Ga. | accessdate=March 26, 2013}}</ref> |
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Blueworms (''[[Perionyx excavatus]]'') may be used in the tropics.<ref>{{cite web |url=http://www.ctahr.hawaii.edu/oc/freepubs/pdf/HG-46.pdf |title=Composting Worms for Hawaii |accessdate=2009-02-22}}</ref> However, ''P. excavatus'' worms are not suitable for worm compost bins in most of the contiguous United States.{{Citation needed|date=December 2009}} |
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These species commonly are found in organic-rich soils throughout [[Europe]] and [[North America]] and live in rotting [[vegetation]], compost, and [[manure]] piles. They may be an [[invasive species]] in some areas.<ref name=autogenerated1 /><ref>{{cite web |url=http://www.nrri.umn.edu/worms/ |title=Great Lakes Worm Watch |accessdate=2009-02-22}}</ref> As they are shallow-dwelling and feed on decomposing plant matter in the soil, they adapt easily to living on food or plant waste in the confines of a worm bin. |
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Composting worms are available to order online, from nursery mail-order suppliers or [[angling]] (fishing) shops where they are sold as [[Bait (luring substance)|bait]]. They can also be collected from compost and manure piles. These species are not the same worms that are found in ordinary soil or on pavement when the soil is flooded by water. |
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==Large scale== |
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Large-scale vermicomposting is practiced in Canada, Italy, Japan, Malaysia, the Philippines, and the United States.<ref>{{cite web |url=http://www.krepublishers.com/02-Journals/JHE/JHE-24-0-000-000-2008-Web/JHE-24-1-000-000-2008-Abst-PDF/JHE-24-1-059-08-1636-%20Aalok-A/JHE-24-1-059-08-1636-%20Aalok-A-Tt.pdf |title=Vermicomposting: A Better Option for Organic Solid Waste Management |accessdate=2009-02-21}}</ref><ref>{{cite web |url=http://www.ecocycle.org/compost/composttea.cfm | title=Compost Tea|accessdate=2009-02-22}}</ref> The vermicompost may be used for farming, landscaping, to create [[compost tea]], or for sale. Some of these operations produce worms for bait and/or home vermicomposting. |
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There are two main methods of large-scale vermiculture. Some systems use a [[windrow]], which consists of bedding materials for the earthworms to live in and acts as a large bin; organic material is added to it. Although the windrow has no physical barriers to prevent worms from escaping, in theory they should not due to an abundance of organic matter for them to feed on. Often windrows are used on a concrete surface to prevent predators from gaining access to the worm population. |
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[[Image:Worm bed wave.svg|thumb|350px|Movement of castings through a worm bed.]] |
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The second type of large-scale vermicomposting system is the raised bed or flow-through system. Here the worms are fed an inch of "worm chow" across the top of the bed, and an inch of castings are harvested from below by pulling a breaker bar across the large mesh screen which forms the base of the bed. |
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Because red worms are surface dwellers constantly moving towards the new food source, the flow-through system eliminates the need to separate worms from the castings before packaging. Flow-through systems are well suited to indoor facilities, making them the preferred choice for operations in colder climates. |
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==Small scale== |
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[[Image:Wormbin.sample.jpg|thumb|right|Demonstration home scale worm bin at a community garden site - painted plywood]] |
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For vermicomposting at home, a large variety of bins are commercially available, or a variety of adapted containers may be used. They may be made of old plastic containers, wood, [[Styrofoam]], or metal containers. The design of a small bin usually depends on where an individual wishes to store the bin and how they wish to feed the worms. |
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Some materials are less desirable than others in worm bin construction. Metal containers often conduct heat too readily, are prone to rusting, and may release [[Heavy metal (chemistry)|heavy metal]]s into the vermicompost. Some [[Cedrus|cedars]], [[Yellow cedar]], and [[Coast Redwood|Redwood]] contain resinous oils that may harm worms,<ref name=raising>{{cite web |url=http://www.p2pays.org/ref/35/34577.pdf |title=Raising Earthworms Successfully |accessdate=2009-03-04}}</ref> although [[Western Red Cedar]] has excellent longevity in composting conditions. [[Tsuga|Hemlock]] is another inexpensive and fairly rot-resistant wood species that may be used to build worm bins.<ref>[http://vermontworms.com/red-wiggler-compost-worm-bin/]{{dead link|date=October 2012}}</ref> |
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Bins need holes or mesh for aeration. Some people add a spout or holes in the bottom for excess liquid to drain into a tray for collection. Worm compost bins made from recycled or semi-recycled plastic are ideal, but require more drainage than wooden ones because they are non-absorbent. However, wooden bins will eventually decay and need to be replaced. |
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Small-scale vermicomposting is well-suited to turn kitchen waste into high-quality [[soil amendment]]s, where space is limited. Worms can decompose organic matter without the additional human physical effort (turning the bin) that [[composting|bin composting]] requires. |
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Composting worms which are detritivorous (eaters of trash), such as the red wiggler ''Eisenia fetidae'', are epigeic (surface dwellers) together with symbiotic associated microbes are the ideal vectors for decomposing food waste. Common earthworms such as ''Lumbricus terrestris'' are anecic(deep burrowing) species and hence unsuitable for use in a closed system.<ref>{{cite web|title=The Worm Dictionary and Vermiculture Reference Center|url=http://www.working-worms.com/content/view/43/68/#d|publisher=Working Worms|accessdate=3 October 2012}}</ref> Other soil species that contribute include [[insect]]s, other worms and [[mold]]s.<ref>{{cite web|last=Trautmann |first=Nancy |url=http://compost.css.cornell.edu/invertebrates.html |title=Invertebrates of the Compost Pile |publisher=Cornell Center for the Environment |date= |accessdate=2012-10-03}}</ref> |
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==Climate and temperature== |
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The most common worms used in composting systems, redworms (''[[Eisenia foetida]],'' ''[[Eisenia andrei]],'' and ''[[Lumbricus rubellus]]'') feed most rapidly at temperatures of 15–25 °C (59-77 °F). They can survive at 10 °C (50 °F). Temperatures above 30 °C (86 °F) may harm them.<ref>Appelhof, p. 3</ref> This temperature range means that indoor vermicomposting with redworms is suitable in all but tropical climates.<ref>{{cite web|url=http://vermicomposters.com |title=Map of vermicomposters |publisher=Vermicomposters.com |date= |accessdate=2012-10-03}}</ref> (Other worms like [[Perionyx excavatus]] are suitable for warmer climates.<ref>Appelhof, p. 41</ref>) If a worm bin is kept outside, it should be placed in a sheltered position away from direct sunlight and insulated against frost in winter. |
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It is necessary to monitor the temperatures of large-scale bin systems (which can have high [[Heat capacity|heat-retentive]] properties), as the [[feedstocks]] used can [[compost]], heating up the worm bins as they decay and killing the worms. |
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==Feedstock== |
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There are few food wastes that vermicomposting cannot compost, although [[meat]] waste and [[dairy products]] are likely to [[putrefaction|putrefy]], and in outdoor bins can attract [[vermin]]. [[Green waste]] should be added in moderation to avoid heating the bin. |
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===Small-scale or home systems=== |
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Such systems usually use kitchen and garden waste, using "earthworms and other [[microorganisms]] |
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to digest organic wastes, such as kitchen scraps".<ref>{{cite journal|first=Piper |last=Selden |first2=Michael |last2=DuPonte |first3=Brent |last3=Sipes |first4=Kelly |last4=Dinges |url=http://www.ctahr.hawaii.edu/oc/freepubs/pdf/HG-45.pdf |title=Small-Scale Vermicomposting |format=PDF |journal=Home Garden |volume=45 |publisher=University of Hawai'i |date=August 2005 |accessdate=2012-10-03}}</ref> |
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This includes: |
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* All fruits and vegetables (including [[citrus]] and other "high acid" foods) |
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* Vegetable and fruit peels and ends |
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* Coffee grounds and filters |
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* Tea bags (even those with high [[tannin]] levels) |
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* Grains such as bread, cracker and cereal (including moldy and stale) |
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* Eggshells (rinsed off) |
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* Leaves and grass clippings (not sprayed with [[pesticides]]<ref>{{cite journal|last=Reinecke|first=SA|coauthors=Reinecke, AJ|title=The impact of organophosphate pesticides in orchards on earthworms in the Western Cape, South Africa.|journal=Ecotoxicology and Environmental Safety |year=2007|month=February|volume=66|issue=2|pages=244–51|pmid=16318873 |url=http://www.aseanenvironment.info/Abstract/41014272.pdf |format=PDF |doi=10.1016/j.ecoenv.2005.10.006}}</ref>) |
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===Large-scale or commercial=== |
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Such vermicomposting systems need reliable sources of large quantities of food. |
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Systems presently operating<ref>[http://www.jgpress.com/BCArticles/2000/110051.html Latest Developments In Mid-To-Large-Scale Vermicomposting]{{dead link|date=October 2012}}</ref> use: |
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* Dairy cow or pig manure<ref>{{cite news|last=Barrett |first=Janice |url=http://www.wormpower.net/pdf/Holstein_World.pdf |title=Putting Worms to Work |publisher=Holstein World |date=August 2005 |format=PDF |accessdate=2012-10-03}}</ref> |
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* [[Sewage sludge]].<ref>[http://www.redland.qld.gov.au/Residents/History/Oursuburbs/Cleveland/Pages/Cleveland%20timeline.aspx ]{{dead link|date=October 2012}}</ref><ref>{{cite web|last=Lotzof |first=M. |url=http://www.p2pays.org/ref/20/19982.htm |title=Very Large Scale Vermiculture in Sludge Stabilisation |publisher=Vermitech Pty Limited |date= |accessdate=2012-10-03}}</ref> Cornell Waste Management has shown that land that had sewer sludge (biosolids) applied was devoid of worms. |
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* Agricultural waste |
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* Food processing and grocery waste |
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* Cafeteria waste |
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* Grass clippings and [[wood chips]] |
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==Harvesting== |
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[[Image:Worm.bin.jpg|right|thumb|Worms in a bin being harvested]] |
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Vermicompost is ready for harvest when it contains few-to-no scraps of uneaten food or bedding {{Citation needed|date=March 2009}}. There are several methods of harvesting from small-scale systems: "dump and hand sort", "let the worms do the sorting", "alternate containers" and "divide and dump."<ref>Appelhof, pp. 79-86</ref> These differ on the amount of time and labor involved and whether the vermicomposter wants to save as many worms as possible from being trapped in the harvested compost. |
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While harvesting, it's also a good idea to try to pick out as many eggs/cocoons as possible and return them to the bin. Eggs are small, lemon-shaped yellowish objects that can usually be seen pretty easily with the naked eye and picked out.<ref>[http://vermontworms.com/red-wiggler-eggs-compost-worm-eggs/]{{dead link|date=October 2012}}</ref> |
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==Properties== |
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Vermicompost has been shown to be richer in many [[nutrient]]s than [[compost]] produced by other [[composting]] methods.<ref>{{cite web|last=Dickerson |first=George W. |url=http://www.cahe.nmsu.edu/pubs/_h/h-164.pdf |title=Vermicomposting: Guide H-164 |publisher=New Mexico State University |format=PDF |date=June 2001 |accessdate=2012-10-03}}</ref> It also has outperformed a commercial plant medium with nutrients added, but needed adjustment for magnesium and pH.<ref>{{cite web|last=Sherman |first=Rhonda |url=http://www.bae.ncsu.edu/topic/vermicomposting/vermiculture/castings.html |title=Earthworm Castings as Plant Growth Media |publisher=Department of Biological and Agricultural Engineering at NCSU |date= |accessdate=2012-10-03}}</ref> |
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However, other studies have shown that the effects of home made, backyard, vermicompost compared to municipal compost were lower in terms of soil microbial biomass,<ref name=autogenerated2>{{cite journal|last=Lazcano|first=Cristina|coauthors=Gómez-Brandón, María; Domínguez, Jorge|title=Comparison of the effectiveness of composting and vermicomposting for the biological stabilization of cattle manure|journal=Chemosphere|date=July 2008|volume=72|issue=7|pages=1013–1019|doi=10.1016/j.chemosphere.2008.04.016 |url=http://webs.uvigo.es/jdguez/wp-content/uploads/2011/10/Comparison-of-the-effectiveness-of-composting-and-vermicomposting.pdf |format=PDF}}</ref> soil microbial activity,<ref name=autogenerated2 /> and yields of a species of [[ryegrass]]. |
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Further, one study concluded that the differences between methods of composting were in large part due to the feedstock, and therefore no generalizations can be made between composts made from varying materials. |
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It is rich in microbial life which converts nutrients already present in the soil into plant-available forms. |
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Unlike other compost, worm castings also contain [[mucus|worm mucus]] which helps prevent nutrients from washing away with the first watering and holds moisture better than plain soil.<ref>Nancarrow, Loren; Taylor, Janet Hogan (1998). [http://books.google.com/books?id=rmtZ91zbxLMC&printsec=frontcover&dq=The+Worm+Book&source=bl&ots=h7KFpfKigc&sig=r_L-YXzDAst_-lmjRkLuXcX3vqo&hl=en&sa=X&ei=DChsUNS2Oei40gHJvIH4CQ&ved=0CDEQuwUwAA#v=onepage&q&f=false ''The Worm Book: The Complete Guide to Gardening and Composting with Worms''] Ten Speed Press. p. 4. ISBN 978-0-89815-994-3.</ref> |
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==Benefits== |
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'''Soil''' |
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* Improves soil aeration |
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* Enriches soil with micro-organisms (adding [[enzymes]] such as [[phosphatase]] and [[cellulase]]) |
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* Microbial activity in worm castings is 10 to 20 times higher than in the soil and organic matter that the worm ingests <ref>{{cite journal|last=Logsdon|first=Gene|title=Worldwide progress in vermicomposting|journal=BioCycle|year=1994|month=October|volume=35|issue=10|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=3324953|page=63}}</ref> |
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* Attracts deep-burrowing earthworms already present in the soil |
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* Improves water holding capacity<ref>Appelhof, p. 111</ref> |
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'''Plant growth''' |
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* Enhances germination, plant growth, and crop yield |
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* Improves root growth and structure |
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* Enriches soil with micro-organisms (adding [[plant hormone]]s such as [[auxins]] and [[gibberellic acid]]){{Citation needed|date=March 2009}} |
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'''Economic''' |
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* Biowastes conversion reduces waste flow to [[landfill]]s |
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* Elimination of biowastes from the waste stream reduces contamination of other recyclables collected in a single bin (a common problem in communities practicing [[Materials recovery facility|single-stream recycling]]<ref>See Wikipedia article on [[single-stream recycling]].</ref>) |
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* Creates low-skill jobs at local level |
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* Low capital investment and relatively simple technologies make vermicomposting practical for less-developed agricultural regions |
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'''Environmental''' |
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* Helps to close the "[[metabolic rift|metabolic gap]]" through recycling waste on-site |
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* Large systems often use temperature control and mechanized harvesting, however other equipment is relatively simple and does not wear out quickly{{Citation needed|date=March 2009}} |
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* Production reduces [[greenhouse gas]] emissions such as [[methane]] and [[nitric oxide]] (produced in landfills or [[incinerator]]s when not composted or through [[methane harvest]])<ref>{{cite web|url=http://www.msnbc.msn.com/id/19459535/ |title=Waste Management to tap landfill methane |publisher=MSNBC |date=June 27, 2007 |accessdate=2012-10-03}}</ref> |
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==As fertilizer== |
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[[Image:Wormbin.bedding.jpg|thumb|right|Mid-scale worm bin (1 m X 2.5 m up to 1 m deep), freshly refilled with bedding]]Vermicompost can be mixed directly into the soil, or [[steep]]ed in water and made into a [[compost tea|worm tea]] by mixing some vermicompost in water, bubbling in oxygen with a small air [[pump]], and steeping for a number of hours or days. |
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The microbial activity of the compost is greater if it is aerated during this period. The resulting liquid is used as a fertilizer or sprayed on the plants. |
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The dark brown waste liquid, or [[leachate]], that drains into the bottom of some vermicomposting systems as water-rich foods break down, is best applied back to the bin when added moisture is needed due to the possibility of [[phytotoxin]] content and organic acids that may be toxic to plants.<ref name=raising/> |
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The pH, nutrient, and microbial content of these fertilizers varies upon the inputs fed to worms. Pulverized limestone, or calcium carbonate can be added to the system to raise the pH. |
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==Troubleshooting== |
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[[Image:Worms and fruit fly eggs.jpg|right|thumb|150px|Worms and fruit fly pupas under the lid of a home worm bin.]] |
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===Smells=== |
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When closed, a well-maintained bin is odorless; when opened, it should have little smell - if any, the smell is earthy.<ref>Appelhof, p. 113</ref> Worms require gaseous oxygen.<ref>Appelhof, p. 92</ref> Oxygen can be provided by airholes in the bin, occasional stirring of bin contents, and removal of some bin contents if they become too deep or too wet. If decomposition becomes anaerobic from excess feedstock added to the bin in wet conditions, or layers of food waste have become too deep, the bin will begin to smell like ammonia. |
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===Moisture=== |
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If decomposition has become anaerobic, to restore healthy conditions and prevent the worms from dying, the smelly, excess waste water must be removed and the bin returned to a normal moisture level. To do this, first reduce addition of food scraps with a high moisture content and second, add fresh, dry bedding such as shredded newspaper to your bin, mixing it in well. |
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===Pest species=== |
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Pests such as rodents and flies are attracted by certain materials and odors, usually from large amounts of kitchen waste, particularly meat. Eliminating the use of meat or dairy product in a worm bin decreases the possibility of pests.<ref>{{cite web |url=http://oacc.info/DOCs/Vermiculture_FarmersManual_gm.pdf |title=Manual of On-Farm Vermicomposting and Vermiculture |accessdate=2009-12-10 | page= 8}}</ref> |
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In warm weather, fruit and vinegar flies breed in the bins if fruit and vegetable waste is not thoroughly covered with bedding. This problem can be avoided by thoroughly covering the waste by at least 2 inches of bedding. Maintaining the correct pH (close to neutral) and water content of the bin (just enough water where squeezed bedding drips a couple of drops) can help avoid these pests as well. |
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===Worms escaping=== |
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Having worms escape is one of the most feared outcomes for many new vermicomposters. Worms generally stay in the bin, but may try to leave the bin when first introduced, or often after a rainstorm when outside humidity is high.<ref>[http://vermontworms.com/compost-worm-escape/ Compost Worm Escape]{{dead link|date=October 2012}}</ref> Maintaining adequate conditions in the worm bin and putting a light over the bin when first introducing worms should eliminate this problem.<ref>[http://vermontworms.com/compost-worm-escape/]{{dead link|date=October 2012}}</ref> |
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===Nutrient levels=== |
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Commercial vermicomposters test, and may amend their products to produce consistent quality and results. Because the small-scale and home systems use a varied mix of feedstocks, the nitrogen, potassium and phosphorus content of the resulting vermicompost will also be inconsistent. NPK testing may be helpful before the vermicompost or tea is applied to the garden. |
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In order to avoid over-fertilization issues, such as [[nitrogen burn]], vermicompost can be diluted as a tea 50:50 with water, or as a solid can be mixed in 50:50 with [[potting soil]].<ref>{{cite book|last=Grant|first=Tim|last2=Littlejohn|first2=Gail|title=Teaching Green, The Middle Years |year=2004|publisher=New Society Publishers|location=Gabriola Island, B.C.|isbn=978-0-86571-501-1 |page=121 |url=http://books.google.com/books?id=v46QjUMYuxkC&pg=PT114&lpg=PT114&dq=vermicompost+and+nitrogen+burn&source=bl&ots=75U3sXc3z2&sig=ojybaKIEAYrU7a9RjZy6SwJeerM&hl=en&ei=7N33SbWLGpyytAPRypXrDg&sa=X&oi=book_result&ct=result&resnum=}}</ref> |
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The mucus produced creates a natural time release fertilizer which cannot burn plants.<ref>{{cite web|url=http://www.vermidirtfarms.net/Castings_or_Compost.php |title=Compost or Worm Castings? |publisher=VermiDirt |date= |accessdate=2012-10-03}}</ref> |
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==See also== |
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{{Portal|Sustainable development}} |
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* [[Composting]] |
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* [[Decompiculture]] |
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* [[Fertilizer]] |
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* [[Home composting]] |
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* [[Waste management]] |
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==Notes== |
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{{reflist|2}} |
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==References== |
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*{{cite book|last=Appelhof|first=Mary|title=Worms Eat My Garbage|year=2007|publisher=Flowerfield Enterprises|location=Kalamazoo, Mich.|isbn=978-0-9778045-1-1|edition=2nd}} |
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==External links== |
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*{{wikiversity-inline}} |
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{{Horticulture and Gardening}} |
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[[Category:Biodegradable waste management]] |
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[[Category:Organic gardening]] |
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[[Category:Composting]] |
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