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Backyard Composting of Yard Waste

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Title:
Backyard Composting of Yard Waste
Physical Description:
Fact sheet
Creator:
Nordstedt, Roger A.
Publisher:
University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication:
Gainesville, FL
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Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
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Published
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"Publication date: November 1991."
General Note:
"Circular 958"

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University of Florida Institutional Repository
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University of Florida
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All rights reserved by the submitter.
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MISSING IMAGE

Material Information

Title:
Backyard Composting of Yard Waste
Physical Description:
Fact sheet
Creator:
Nordstedt, Roger A.
Publisher:
University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication:
Gainesville, FL
Publication Date:

Notes

Acquisition:
Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status:
Published
General Note:
"Publication date: November 1991."
General Note:
"Circular 958"

Record Information

Source Institution:
University of Florida Institutional Repository
Holding Location:
University of Florida
Rights Management:
All rights reserved by the submitter.
System ID:
IR00003584:00001


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Circular958 November1991BackyardCompostingofYardWaste1 RogerA.Nordstedt,AnneW.BarkdollandM.ElizabethWill2WHATISCOMPOSTING?Compostingisabiologicaldecompositionof organicwastesbybacteria,fungi,worms,andother organismsoccurringundercontrolledaerobic conditions.Theorganismsusecarbon,nitrogen,and othernutrientsreleasedfromtheorganicmatter duringthedecompositionprocess.Theresultisan accumulationofdark,friable,partiallydecomposed material.Inthehomeyard,theprocesscanbe managedbyplacingtheraworganicmaterialsina backyardcompostingstructure.Rawmaterialsfor compostingincludeleaves,pineneedles,twigs,grass, andvegetablewastesfromthegardenandkitchen. Propermanagementisakeyfactor,sincean unmanagedcompostheapmaybecomeaneyesore andanodornuisance.WHYCOMPOST?Compostingofyardtrashisanenvironmentally soundwayofreducingsolidwastebyrecyclinga usefulresourcewhereitisgenerated.Yardtrash materialmakesupabout20%ofthevolumeof collectedmunicipalsolidwaste,andseasonallyitmay accountforupto80%.Keepingthismaterialoutof thewastestreamwillextendtheusefullifeofexisting landfillsandslowtheneedtoacquiremorelandfor futurelandfills.Compostingalsocreatesausefulsoil amendment.Mostpeoplecompostforpersonal reasons,suchastheneedfororganicmaterialinthe garden,and/orasawayoffulfillingtheircommitment torecycling.Whateverthemotivation,an understandingoftherequirementsforsuccessful compostingisnecessary.WHATCANBECOMPOSTED?Manytypesoforganicmaterialsarereadily composted.Yardtrashsuchasfallenleaves,remains ofgardenplants,non-woodyplanttrimmings,and grassclippingscanbecomposted,aswellasvegetable kitchenscraps.Some"raw"(uncomposted)organic materials,suchasgrass,weeds,andgreengarden plantwaste,containfairlylargeamountsofnitrogen. Others,suchasleavesandsmalltwigs,containmuch lessnitrogenandahigherproportionofcarbon. Materialswithhighernitrogenlevelsmaydecompose sorapidlythatsomeofthenitrogenandother nutrientsarelostbeforetheycanbeusedbygrowing plants.Excessnitrogenlevelsmayalsocausenitrogen tobelostasammoniathuscausingodorproblems. Materialscontaininglowlevelsofnitrogenandhigh levelsofcarbonmaycausenitrogendeficienciesinthe plantsiftheyareaddeddirectlytothesoil.Thisis causedbythemicroorganismswhichusenitrogenas theydegradeorganicmaterialthuscompetingwith theplantsfornitrogen.Ifnitrogenispresentin insufficientquantitiesplantnitrogendeficienciesmay result.Toavoidthisproblem,rawmaterialswithhigh nitrogenshouldbecombinedwiththosewithlow nitrogen.Thiswillresultinabettercompost. 1.ThisdocumentisCircular958(availableonlyviaCD-ROM),FloridaCooperativeExtensionService,InstituteofFoodandAgricultural Sciences,UniversityofFlorida.Publicationdate:November1991. 2.RogerA.Nordstedt,associateprofessor;AnneW.Barkdoll,post-doctoralassociate;M.ElizabethWill,formerpost-doctoralassociate, AgriculturalDepartment,CooperativeExtensionService,InstituteofFoodandAgriculturalSciences,UniversityofFlorida,GainesvilleFL 32611. TheInstituteofFoodandAgriculturalSciencesisanequalopportunity/affirmativeactionemployerauthorizedtoprovideresearch,educational informationandotherservicesonlytoindividualsandinstitutionsthatfunctionwithoutregardtorace,color,sex,age,handicap,ornational origin.Forinformationonobtainingotherextensionpublications,contactyourcountyCooperativeExtensionServiceoffice. FloridaCooperativeExtensionService/InstituteofFoodandAgriculturalSciences/UniversityofFlorida/ChristineTaylorStephens,Dean

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BackyardCompostingofYardWaste Page2Withproperlawnmanagement,grassclippingsdo notneedtoberemovedfromthelawn.Ifgrass clippingsarecollectedandcomposted,theyshouldbe mixedwithotheryardwastetoprovidebulkanda properratiooftwoimportantplantnutrients,carbon andnitrogen(C/N).Otherwise,theclippingsmay compactandrestrictairflowinthecompostpileand causeunpleasantodors. Twigs,branchesgreaterthan1/4inchindiameter andfibrouspalmfrondsshouldbeprocessedina shredder/chipperbeforecomposting.Leaves, especiallywaxytypessuchasliveoak,laureloak, wateroak,andmagnolia,alsobenefitfrombeing shreddedbeforecomposting.Largerwoodymaterial canalsobecompostedbutrequiresalongertimeto decompose.Whenchippedtoasmallsizeand supplementedwithanitrogensource,decomposition canbeaccelerated. Mostplantdiseaseorganismsandplantseedsare destroyedbyhightemperatures(130-140F).These hightemperaturesmaybereachedinthepileduring propercomposting,howeveritisusuallydifficultina homecompostingsystemtomixapilewellenoughto bringallwastestothecenterandassurecomplete destructionofseedsandpathogens.Thisbeingthe case,itisnotadvisabletoaddlargeamountsofseedladenweedsordiseasedplantstothecompostpileif theresultingcompostistobeusedinthegarden. Thehightemperaturesgeneratedincompostalso inhibitharboringandbreedingofinsectsinthe compostpile.Plantstreatedwithpesticidesshould notbeaddedtothecompostpile. Kitchenwastes,suchasvegetableandfruitscraps, coffeegrounds,andeggshells,mayalsobeaddedto thecompostpile,buttheyshouldbeincorporated immediatelytoavoidodors.Althoughmeatscraps, fat,bones,grease,anddairyproductsare compostable,theyshouldnotbeincorporatedinthe homecompostpile.Theseitemsattractanimals, createnuisanceodors,andareslowtodecompose. Sawdustmayalsobeaddedtothecompostpilein moderateamountsifahighnitrogenmaterialisbeing compostedorifadditionalnitrogenisapplied. Approximately1poundofnitrogen(6cupsof ammoniumnitrate)isrequiredforevery100pounds ofdrysawdust.Woodashesareasourceoflimeand shouldbeaddedtoacompostpileonlyinsmall amountsifatall.Largeamountsoflimewillcause lossofnitrogenfromthepile. Althoughordinaryblack-and-whitenewspaperis compostable,ithasalownitrogencontentand decomposesslowly.Ittendstocompactandrestrict airflowunlessshredded.Itisrecommendedthat newspaperberecycledratherthancomposted.Other organicmaterialsthatcanbeusedtoaddnutrients, particularlynitrogen,toacompostpileinclude livestockmanures.COMPOSTINGPRINCIPLESRapidcompostingrequiresanenvironmentin whichmicroorganismswillthrive.Optimummoisture, aeration,temperature,particlesizeandcarbonto nitrogenratioareimportantforefficientcomposting.MoistureMicrobialactivityrequiresadequatemoisture, usually40-60%.Atthismoisturelevel,ahandfulof thecompostwillfeelwetbutwatercannotbe squeezedoutofit.Thecompostpilemustbekept moist,butnotsoggy.Materialswhicharetoowetwill compactandrestrictthemovementofairthroughthe pile.Itmaybenecessarytoaddmorewaterduring thecompostingperiodiftheweatherisdry.AerationMicrobesactiveincompostingrequireoxygento efficientlybreakdownorganicmaterials.Bulky materialssuchasleaves,pineneedles,chippedtwigs, andstrawkeepthecompostpilefromsettlingand allowairtoenter.Thecompostpileshouldbe periodicallyturnedormixedtoincorporateoxygen. Heatisgeneratedbythemicrobesduringthe decompositionprocess.Turningalsoshiftsmaterial fromtheouter(cooler)partofthepiletothecenter (hotter).Thefrequencyofturningdependsuponthe materialsbeingcomposted,thecomposttemperature andthemoistureconditions,butgenerallyshouldbe doneonaweeklybasisinwarmweather.Turning shoulddefinitelybedoneifthetemperatureinthe centerofthepilereaches140Forifodorsare present.TemperatureTemperatureisafunctionofpilesize,oxygenand moisturecontent.Toreachtemperaturesdesirablein composting,apilemustbelargeenoughtoprovide aninsulatingeffectfortheinteriorofthepile. Temperatureisanimportantenvironmentalfactor affectingbiologicalactivity,andcompostingis

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BackyardCompostingofYardWaste Page3dependentonthisactivity.Eachtypeoforganismhas anoptimumtemperaturerange.Compostingis designedtofunctionintherangeof95F-160F. Themosteffectiverangeforcompostingseemstobe 122F-131F.Highertemperaturesof131F-140F maybedesirabletodestroyweedseedsorplant pathogens.Attemperaturesabove149Fmanyofthe organismsinvolvedincompostingbecomeinactiveor die.ParticlesizeReductionintheparticlesizeofrawmaterialswill increasethespeedofthecompostingprocessby increasingthesurfaceareaavailableformicrobesto attack.Itisthereforeagoodideatoputsmalllimbs andtwigsthroughachipperbeforecomposting. Leavesmaybeprocessedinashredderorcutupwith alawnmower,preferablywithamulchingattachment. Thiswillbreakthewaxycoatingandexposethemore easilydegradedinteriorofleaves.Sizereductionalso reducesthevolumeofthecompostpile,thereby savingspace.Particlesizecouldbetoosmallifthe pilewereconstructedofmaterialthesizeofsawdust. Thiswoulddecreaseaeration,reducetherateof compostingandperhapscauseanaerobicconditions.NitrogenlevelMicrobialactivityisaffectedbytheC/Nratioof organicmaterial.Materialshighincarbonrelativeto nitrogen(i.e.C/N>30),suchasstrawandsawdust, willdecomposeveryslowlyunlessasourceofnitrogen isadded.MaterialswithalowC/Nratioaregood sourcesofnitrogenandincludemanure,inorganic fertilizer,vegetabletablescrapsandgrassclippings. TheoptimumC/Nratioforrapidcompostingisabout 30/1orless.TheapproximateC/Nratioformaterials (Table1)commonlyusedinbackyardcomposts rangesfromabout15to600.DESIGNINGANDBUILDINGACOMPOSTERThetypeofcomposterwhichisusedshouldbe theonethatbestsuitstheneedsandcapabilitiesof theuser.Theyvarygreatlyinexpenseandinthe amountofphysicallaborrequiredtomanagethem. Severaltypesofunitsaredescribedbelowthatcanbe madeathome,althoughunitsofsimilardesigncan alsobepurchased. Table1. ApproximateC/NRatioforvariousmaterials commonlyusedinbackyardcomposts. Material C/NRatio FruitWastes 35 GrassClippings 20 Leaves 60 RottedManures 20 Sawdust/Wood 600 Straw 100 TableScraps 15 Figure1. DrumComposterDrumcomposterIfyouhaveasmallamountofwasteorwantto makeonlyasmallamountofcompost,composting canbedoneinacoveredgarbagecanorothermetal orplasticcan(Figure1).Holes(tinchindiameter) shouldbemadeinthesidesandbottomofthedrum anditshouldbesetuponblockstoallowair circulationandwaterdrainage.Thematerialcanbe mixedandaeratedwithagardentoolorbyturning thedrumonitssideandrollingitaroundonthe groundifithasasecuredlid.Thedrumcanalsobe placedonrollersorcasterstomaketurningeasier. Moreelaboratedrumcomposterscanbefabricatedby mountingthebarrelonapipe.Thepipecanbe placedthroughthesidesorthroughtheendsofthe barrel.Reinforcingcanbeprovidedwithapipefloor flange.Pipefloorflangesareavailableatmost hardwarestores.Thebarrelcanbesuspendedby supportingthepipesonposts,blocks,orother structure.Ahingeddoorcanalsobeplacedonthe barreltofacilitateloadingandunloadingofthedrum composter.Turningofthecompostingmaterialis alsomucheasierwiththistypeofdrumcomposter.

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BackyardCompostingofYardWaste Page4 Figure2. WovenorWeldedWireBinWovenorweldedwirebinAnothermethodistobuildapilewithinapenof flexiblewovenwireorsnowfencing(Figure2).The structuremaybe3to5feetindiameterand4feet high.Advantagesofthisdesignarethataircan circulatefreelythroughthepile,anditiseasyand inexpensivetorelocate.Toturnthepile,thewire cylinderisdisconnected,removedfromaroundthe currentpile,andsetupagaincloseby.The compostingmaterialcanthenbeplacedbackinthe newlylocatedbin.Thisdesigncanbemademore stableandeasiertomanagebyattachingthewireto woodormetalfencepostswithagateorremovable panelononeside.Thematerialwouldbeturned withapitchforkoracompostturner(described below).Three-chamberbinAdurablestructureforrapidcompostingisthe three-chamberbin(Figure3).Itholdsafairlylarge amountofcompostandallowsgoodaircirculation. Thisdesignworksasanassemblylinewiththe compostineachbinbeingatadifferentstageinthe decompositionprocess.Therawmaterialisstartedin thefirstbinwhereitisallowedtoheatupfor1to2 weeks.Itisthenmovedintothenextbinandleftfor another1to2weekswhileanewbatchisstartedin thefirstbin.Finally,thematerialinthemiddlebin isplacedinthelastbintocuretoafinishedcompost. Thistypeofstructureisnotlimitedtothreebins. Fourormorebinsmaybeconstructed,alwaysleaving atleastoneemptybinforfreshmaterial. Goodconstructionmaterialsforthethreechamberbinarewoodthathasbeentreatedwitha preservativetopreventrottingandvinyl-coatedwire mesh.Eachbinshouldbeabout3feetby5feetand Figure3. Three-ChamberBin3ormorefeethigh.Thefloorinthebinscanbe earthen,wood,orotherporousmaterial.Removable woodslatsonthefrontofthebinscanbeheldin placebyposts.Theslatswillincreasethecapacityof thebinsandmaketheloadingandunloadingofthe binsmucheasier. Thethree-chamberbincanalsobemadewith concreteblocksorbrickslaidtogether.Spacesmay beleftbetweenthebricksorblockstoallowfreeair circulationintothecompostmaterial.Theblockscan alsobemortaredorfastenedtogetherwithsurface bondingcementforamorepermanentstructure. However,provisionsshouldbemadeforaeration holesiftheblocksaremortaredorbondedtogether.COMMERCIALLYAVAILABLECOMPOSTERS ANDACCESSORIESSeveraltypesofcompostunitsandavarietyof usefulaccessoriescanbepurchasedfromgarden supplystoresandmail-ordercatalogs.The compostingunitsrangeinpricefromlessthan$100 toafewhundreddollars.Theyofferanalternativeto thosewhodonotwanttoconstructtheirownunit. Durabilityandeaseofloading,unloading,andturning areimportantfeaturestolookforinacomposter. Thecommercialcomposters,designedtomake theprocessaslaborfreeandattractiveaspossible, aregenerallyoftwodesigns;drumtumblers(Figure 1)andbins(Figure2andFigure3).Thebinsare constructedofeitherplasticorgalvanizedmetal,sit directlyontheground,havehingedorremovablelids, andareattractivelymadeandanimal-resistant. Loadingandturninginstructionsareusuallyprovided withthecomposter.Thedrumstylecompostersare metalormoldedplasticbarrelsmountedonastand, eitherverticallyorhorizontally.Thematerialis loadedandunloadedthroughadooronthesideor ononeend.Thecompostisturnedbyrotatingor tumblingthedrum.Desirablefeaturesincludequality ofconstruction,heightandsizeoftheloadingdoor, andeaseofturning.Theloadingdoorshouldbehigh enoughtoaccommodateawheelbarrowbutnotso

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BackyardCompostingofYardWaste Page5highastonecessitateliftingthematerialabovethe Figure4. CompostAccessories:compostturner, thermometer,screen.waistduringloadingandunloading.Thevertical drumunitstendtobealittlemoreawkwardtoturn whenthedrumisfull. Availableaccessoriescanmakecompostingmore efficientandeasier.Asnotedearlier,iftheparticle sizeoftherawmaterialgoingintothecomposteris smaller,thecompostingprocesswilltakelesstime. Severalshreddersandchipperspoweredbyanelectric motororgasengineareavailable.Choosingthe properequipmenttodothejobisimportant. Machinesthatarecalled"leaf-shredders"areoften inexpensiveandpoweredbyelectricity.Thecutting oftheleavesmaybedonewitharapidlyrotating, replaceablenylonfilament.Theyarenotdesignedto shredlargematerial.Chipper/shredders,ontheother hand,comeinseveralsizesdependinguponthesize ofmaterialtobeprocessedanddesiredcapacity. Theyareconsiderablymoreexpensivethanleaf shredders,rangingfromafewhundredtoseveral hundreddollars. Otheraccessoriesincludethermometersfor measuringtheinternaltemperatureofthecompost pileandscreensforprocessingthefinishedcompost (Figure4).Thescreenscanbeusedtoremove materialstoberecycledforfurthercomposting,orto sizethecompostforspecificenduses.Thereisalso acompostturneravailablethat,wheninsertedintoa compostpileandthenwithdrawn,pullsmaterialfrom insidethepiletotheoutside(Figure4).Thisaction mixesandaeratesthecompostingmaterial.Various typesofinoculumarealsoavailableforcompostpiles. Theorganismsnecessaryforcompostingarerarelya limitingfactorastheyarealreadypresentonthe materialtobecomposted.Researchhasnotshown inoculumadditontobenecessaryforcomposting exceptperhapsinspecialcases.Theseaccessoriescan bepurchasedthroughmailordercatalogsadvertised ingardeningmagazines.GETTINGSTARTED-BUILDINGTHE COMPOSTPILEChoosealocationforthecompostpilewhichis nearawaterspigot.Considerhowyouwillgetthe rawmaterialstothepileandhowyouwillmovethe finishedcomposttoareasinwhichitwillbeused.A partlysunnyareaprotectedfromdryingwindsand withgooddrainageisbest.Thesizeofthepilemay varygreatlywiththeamountofmaterialsonhand.It shouldnotbelessthan3feethighand3feetwide,or itmaynotmaintainthehightemperaturesnecessary forrapiddecomposition.Drumcompostersshouldbe filledtonomorethanabout2/3oftheircapacityin ordertoassurepropermixing. Thecompostpileshouldbebuiltinlayersorall ingredientsshouldbethoroughlymixed.Thishelps ensurethepropermixingofnitrogen-richandcarbonrichmaterials.Thereareavarietyof"recipes"for addingmaterialstopiles;however,somegeneralrules apply.Successivelayers,each3to4inchesdeep,of differenttypesofmaterialsshouldbeused: 1.nitrogen-containingmaterialsuchasmanure, kitchenwaste,grassclippings,orinorganic fertilizerscontainingnitrogen. 2.bulkymaterialsuchasleaves,chippedtwigs, straw,orsawdust. Watershouldbeappliedbetweeneachcompleted setoflayerstoachievethepropermoisturecontent. Thematerialshouldbewet,butnotsowetthatyou cansqueezewateroutofitwithyourhand.MAINTAININGTHECOMPOSTPILEThecompostpileshouldbeperiodicallymixedto incorporateoxygen(whichisrequiredforcomposting) andtoexposeseeds,insectlarvae,andpathogens (disease-causingorganisms)tothelethaltemperatures atthecoreofthepile.Thiscanbedonewitha pitchfork,shovel,oratoolthatcanbepurchased whichisspeciallymadeforthistask.Checkthe internaltemperatureofthecompostpileregularly andturnthepilewhenitreachesabout140F.Piles shouldbeturnedimmediatelyifammoniaoroffensive odorsassociatedwithanaerobicconditions(lackof oxygenorair)aredetected.Anaerobicconditionscan becausedbytoomuchwaterorbycompaction.

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BackyardCompostingofYardWaste Page6Withinafewweeksafterstarting,thepileshouldbe hotinthecenter.Heatingindicatesthatthematerial iscompostingproperly.Temperatureswithinthe compostpileincreaseduringthedecomposition processandmayapproach150Forhigher.Failure toheatmaybetheresultoftoolittleortoomuch water,alackofnitrogen,airnotgettingintothe centerofthepile(materialpackedtootightly),orthe pilebeingtoosmall.Asthematerialdecomposes,the pilemayshrinktoaboutone-halfitsoriginalvolume. Thecompostingprocessiscompletewhenthereisno heatproducedinthepileafterturningandthe materialisdark,friableanddoesnotcontain distinguishableplantpartslikeleaves. Thecompostisreadytouseafter1to12months, dependingonthedegreeofinitialshreddingandlevel ofmanagement.Thematerialwillbedarkand crumblyintexture,fairlydry,andhaveanearthy odor.Dependingontheintendeduseofthe compost,itmaybedesirabletoputthematerial througha1/2inchscreenbeforeusing.Thelarger particlescanbereturnedtothecompostpileto decomposefurther.USINGCOMPOSTAROUNDTHEHOME SoilAmendmentAlayerofcompost1to3inchesthickmaybe workedintogardensoil.Whenincorporatedinthis way,compostaddssmallamountsofnutrientstothe soilandservesto: 1.increaseasandysoil'sabilitytoretainadded moisture,therebyreducingdroughtdamage, 2.makethesoileasiertocultivate, 3.improvedrainageandaerationofclayeysoils, 4.supplyverysmallamountsofmanyessential elementsneededforplantgrowth, 5.reduceadverseeffectsofexcessiveacidityand overfertilizationbyincreasingthebuffering capacityofthesoil, 6.increasethebiologicalactivityofearthwormsand othersoilorganisms,and 7.allowthesoiltoholdmoreplantnutrientsfor longerperiodsoftime.MulchCompostcanalsobeusedtoreplacematerials suchascypressmulchandstrawasamulching material.Itmaybeappliedina2to3inchlayeron topofthesoilaroundtrees,shrubs,flowers,and gardenplants.Organicmulchesarevaluablebecause they: 1.reducerainfallrunoff,therebyincreasingthe wateravailabletoplants, 2.decreasewaterevaporationlossfromsoil, 3.helppreventsoilerosionlossbywindorwater, 4.helpcontrolweeds, 5.keepthesoilcoolerinhotweatherandwarmerin coldweather,and 6.presentapleasingappearance.PottingMixCompostmayalsobeblendedwithsoil,perlite, sandandothermaterialstomakeapottingmixfor containerizedplants.