Composting 101Composting 101

The what, when, The what, when,

where, why and where, why and

how of compostinghow of composting

Home Page: http://www.extension.umn.edu/county/sherburne/mgardeners

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Minnesota waste factsMinnesota waste facts

• Statewide recycling rate - 47.2%Statewide recycling rate - 47.2%

• Minnesotans threw away Minnesotans threw away 3 million tons3 million tons of of garbage in 1999garbage in 1999

• Organic materials comprise of 25.4% of Organic materials comprise of 25.4% of statewide residential waste (most of which is statewide residential waste (most of which is compostable)compostable)

• Paper products make up Paper products make up 30.8% of statewide 30.8% of statewide residential wasteresidential waste

What is compost?What is compost?

• End product of the decomposition of End product of the decomposition of organic materials by decomposersorganic materials by decomposers

• Valuable soil amendmentValuable soil amendment• Dark, crumbly and earthy Dark, crumbly and earthy

smelling materialsmelling material• A resource that can be A resource that can be

utilized in your own back utilized in your own back yardyard

Why should I compost?Why should I compost?

• There are many benefits to There are many benefits to compostingcomposting– Valuable soil amendmentValuable soil amendment– Effective mulchEffective mulch– Reduction in wasteReduction in waste

• Improves soil structureImproves soil structure– Increases aerationIncreases aeration– Holds moistureHolds moisture– Especially important in sandy soilEspecially important in sandy soil

• Promotes plant growthPromotes plant growth– Contains essential micronutrientsContains essential micronutrients

• Stores nutrientsStores nutrients– Porous structure stores nutrientsPorous structure stores nutrients

Soil amendmentSoil amendment

Soil amendmentSoil amendment

• Flower and vegetable gardensFlower and vegetable gardens– Dig or till 8 to 10 inch deepDig or till 8 to 10 inch deep– Mix 3 to 4 inches of compost through entire Mix 3 to 4 inches of compost through entire

depthdepth

• Seeding new lawnsSeeding new lawns– Till soil 6 inches deepTill soil 6 inches deep– Mix in 4 inches of compostMix in 4 inches of compost

MulchMulch

• Suppress weedsSuppress weeds• Maintain moisture levelsMaintain moisture levels• Control temperatureControl temperature• Prevent soil erosionPrevent soil erosion

MulchMulch• GardensGardens

– Sift compost to remove large, woody materialSift compost to remove large, woody material– Apply 1/2 to 1 inch layerApply 1/2 to 1 inch layer– Keep a few inches away from base of plantsKeep a few inches away from base of plants

• Trees and shrubsTrees and shrubs– Remove sod from base of plantRemove sod from base of plant– Use coarse compostUse coarse compost

• Erosion controlErosion control– Use 2 to 4 inches coarse compostUse 2 to 4 inches coarse compost

Reduce wasteReduce waste• Reduce the amount of waste sent to Reduce the amount of waste sent to

landfills and incineratorslandfills and incinerators• Often illegal to dispose of yardwaste Often illegal to dispose of yardwaste

with other municipal solid wastewith other municipal solid waste

How does compost happen?How does compost happen?• Organic material is processed (for free) by numerous Organic material is processed (for free) by numerous

decomposersdecomposers– BacteriaBacteria– FungiFungi– InvertebratesInvertebrates

WormsWorms NematodesNematodes SpringtailsSpringtails

• Decomposers need food, nutrients, air and water Decomposers need food, nutrients, air and water (you will need to supply these)(you will need to supply these)

• Decomposers also need heat but they supply their Decomposers also need heat but they supply their ownown

Decomposers – microorganisms Decomposers – microorganisms and soil animalsand soil animals

The food web The food web in your in your compost pile compost pile supports a supports a wide variety of wide variety of lifeforms from lifeforms from microscopic microscopic bacteria to bacteria to larger beetles larger beetles and worms.and worms.

Decomposers - bacteriaDecomposers - bacteria

• Most numerous organisms in compost pileMost numerous organisms in compost pile• Don’t need to be added to compost pile, they Don’t need to be added to compost pile, they

are present virtually everywhere!are present virtually everywhere!• Generate heat associated with compostingGenerate heat associated with composting• Perform the primary breakdown of organic Perform the primary breakdown of organic

materialsmaterials• There are different bacteria There are different bacteria present at different temperaturespresent at different temperatures

• Psychrophilic bacteriaPsychrophilic bacteria– Ideal temperature is around 55°F but they are Ideal temperature is around 55°F but they are

able to survive right down to 0°Fable to survive right down to 0°F

• Mesophilic bacteriaMesophilic bacteria– Thrive at temperatures between 70-90 °F and can Thrive at temperatures between 70-90 °F and can

survive from 40-110 °Fsurvive from 40-110 °F

• Thermophilic bacteriaThermophilic bacteria– Work fastest in temperatures from 104-170 °FWork fastest in temperatures from 104-170 °F– Most efficient decomposersMost efficient decomposers

Bacteria groupsBacteria groups

• Interesting fact - “less than a teaspoon of Interesting fact - “less than a teaspoon of

the common bacteria Escherichia coli, the common bacteria Escherichia coli,

would become a pound in 3 hours and a would become a pound in 3 hours and a

mass the size of the Earth in a day and a mass the size of the Earth in a day and a

half if sufficient food and proper conditions half if sufficient food and proper conditions

were available!”were available!”

Decomposers - bacteriaDecomposers - bacteria

Decomposers - fungiDecomposers - fungi

• Perform primary decompositionPerform primary decomposition• Identified by their root-like fibers or Identified by their root-like fibers or

presence of mushroomspresence of mushrooms• Not as efficient as bacteriaNot as efficient as bacteria• Less temperature tolerant Less temperature tolerant

than bacteriathan bacteria

Decomposers - nematodesDecomposers - nematodes• Most abundant invertebrate in the soilMost abundant invertebrate in the soil• Usually less then 1 millimeter in lengthUsually less then 1 millimeter in length• Prey on bacteria, protozoa, fungal spore Prey on bacteria, protozoa, fungal spore

and each otherand each other

Decomposers - mitesDecomposers - mites• Called fermentation mites or mold mitesCalled fermentation mites or mold mites• Transparent-bodied creaturesTransparent-bodied creatures• Feed on yeastFeed on yeast• Masses often develop over fermenting Masses often develop over fermenting

surfacessurfaces

Decomposers - collembulaDecomposers - collembula• Also know as springtailsAlso know as springtails• Feed mainly on fungi but also eat Feed mainly on fungi but also eat

nematodes and organic detritusnematodes and organic detritus• Major population controlling factor of Major population controlling factor of

fungifungi

Decomposers - wolf spidersDecomposers - wolf spiders

• Build no websBuild no webs• Run freely hunting preyRun freely hunting prey• Prey on all sizes of arthropodsPrey on all sizes of arthropods

Decomposers - centipedeDecomposers - centipede

• Frequently found in soil and compost Frequently found in soil and compost microcommunitiesmicrocommunities

• Prey on almost any type of soil Prey on almost any type of soil invertebrate near their size or slightly invertebrate near their size or slightly largerlarger

Decomposers - sow bugDecomposers - sow bug

• Feed on rotting woody material and leaf Feed on rotting woody material and leaf tissuetissue

• Also know as pill bugs or roly polysAlso know as pill bugs or roly polys

Decomposers - ground beetleDecomposers - ground beetle

• Many different types can be found in and Many different types can be found in and around compost pilesaround compost piles

• Most feed on other organisms, but some Most feed on other organisms, but some feed on seeds and vegetable matterfeed on seeds and vegetable matter

Decomposers - redwormsDecomposers - redworms• Coat processed organic material with Coat processed organic material with

mucus films thatmucus films that– Binds small particles togetherBinds small particles together– Leads to loose and well drained soilLeads to loose and well drained soil– Protects soil against nutrient leachingProtects soil against nutrient leaching

Other compost residents - pestsOther compost residents - pests

• Common pests may include house and fruit Common pests may include house and fruit flies, rodents, raccoons, and domestic flies, rodents, raccoons, and domestic animals such as cats and dogsanimals such as cats and dogs

• Proper bin maintenance and selective Proper bin maintenance and selective material usage will reduce your risk of pest material usage will reduce your risk of pest problemsproblems

Pest controlPest control

• Avoid composting meat and dairy Avoid composting meat and dairy products and other fatty foodsproducts and other fatty foods

• Avoid adding pet food or feces to your Avoid adding pet food or feces to your compost pilecompost pile

• Cover other food waste with a layer of Cover other food waste with a layer of grass, straw, leaves, paper or finished grass, straw, leaves, paper or finished compostcompost

What are the key “ingredients”?What are the key “ingredients”?

• Materials (C:N ratio)Materials (C:N ratio)• Moisture and aerationMoisture and aeration• Particle size/surface areaParticle size/surface area• TemperatureTemperature

C:N RatioC:N Ratio• All living organisms need relatively All living organisms need relatively

large amounts of carbon and smaller large amounts of carbon and smaller amounts of nitrogenamounts of nitrogen

• Microorganisms in compost use carbon Microorganisms in compost use carbon for energy and nitrogen for protein for energy and nitrogen for protein synthesissynthesis

Generally...Generally...

• Green Green materials = nitrogen– ex. green grass clippings

• Brown Brown materials = carbon– ex. autumn leaves, straw

Average Carbon:Nitrogen Ratios

Food Scraps 15:1 GREENSGREENSGrass Clippings 19:1Rotted Manure 25:1

30:1 Ideal for CompostingCorn Stalks 60:1Leaves 40-80:1Straw 80:1 BROWNSBROWNSPaper 170:1Sawdust, woodchips 500:1

• The ideal ratio of carbon:nitrogen of 30:1 will ensure The ideal ratio of carbon:nitrogen of 30:1 will ensure maximum bacteria decompositionmaximum bacteria decomposition

• Mix based on weight not volumeMix based on weight not volume• These are only guidelines, actual values may very (Ex. These are only guidelines, actual values may very (Ex.

leaves from different trees will vary in their carbon content)leaves from different trees will vary in their carbon content)

Moisture and aerationMoisture and aeration

• All compost organisms need air and water All compost organisms need air and water to surviveto survive

• Strive for moisture content around 50%Strive for moisture content around 50%– Without 40% the bacteria will slow downWithout 40% the bacteria will slow down– At 80% and above there is not enough airspace and At 80% and above there is not enough airspace and

aerobic decomposition occurs which is slower and aerobic decomposition occurs which is slower and leads to odor problemsleads to odor problems

• Avoid compacting materials - this Avoid compacting materials - this limits aeration in your pilelimits aeration in your pile

Moisture and aerationMoisture and aeration• Optimal moisture levels occur when Optimal moisture levels occur when

compost is as moist as a wrung out compost is as moist as a wrung out spongesponge

• When watering a dry pile be sure to mix When watering a dry pile be sure to mix Water will just shed off a dry pile Water will just shed off a dry pile

• Mixing once or twice a month will Mixing once or twice a month will increase rate of decomposition by increase rate of decomposition by increasing air spacesincreasing air spaces

• Takes 3–6 X’s longer if not turnedTakes 3–6 X’s longer if not turned

• Particle size is an Particle size is an important factor in important factor in compostingcomposting

• Reducing particle size Reducing particle size increases the surface area increases the surface area available for decomposersavailable for decomposers

• However, if the pieces are However, if the pieces are too small they may too small they may compact together and compact together and limit aerationlimit aeration

• A mixture of small and A mixture of small and larger particles is ideallarger particles is ideal

Particle sizeParticle size

TemperatureTemperature

• High temperature High temperature compost pilecompost pile– Faster Faster

decompositiondecomposition– Helps insure Helps insure

weeds and weeds and pathogens are pathogens are killedkilled

What can be composted?What can be composted?

Grass and yard trimmings/clippingsGrass and yard trimmings/clippings

LeavesLeaves

Coffee grounds/filtersCoffee grounds/filters

Tea leaves/bagsTea leaves/bags

Fruits and vegetable trimmingsFruits and vegetable trimmings

Wood chipsWood chips

SawdustSawdust

Egg shellsEgg shells

Livestock manureLivestock manure

What should not be composted?What should not be composted?

Diseased or insect infested plantsDiseased or insect infested plants

Cat and dog manureCat and dog manure

Evergreen needlesEvergreen needles

Poison ivy and other poisonous plantsPoison ivy and other poisonous plants

Weeds that contain seedsWeeds that contain seeds

Meat and animal productsMeat and animal products

Fatty foodsFatty foods

Dairy productsDairy products

Compost bin sizeCompost bin size

• For fast efficient composting your bin needs to For fast efficient composting your bin needs to bebe– Large enough to hold heat and moistureLarge enough to hold heat and moisture– Small enough to admit air through the centerSmall enough to admit air through the center• Rule of thumbRule of thumb– A compost pile need to A compost pile need to

be at least 3ft. by 3ft. by be at least 3ft. by 3ft. by 3ft.3ft.

– Upper limits are about Upper limits are about 5ft. by 5ft. by any length5ft. by 5ft. by any length

Building your compost pileBuilding your compost pile• Build in layersBuild in layers

– 8 to 10 inches of ‘brown’ material8 to 10 inches of ‘brown’ material– Several inches of ‘green’ materialSeveral inches of ‘green’ material– One inch of soilOne inch of soil

• Establish proper Establish proper moisture contentmoisture content

• Avoid compacting Avoid compacting materialsmaterials

Compost bin typesCompost bin types

• There is a great deal of variety in There is a great deal of variety in composting structurescomposting structures

• Compost bins vary in their cost, Compost bins vary in their cost, required labor, volume, and time required labor, volume, and time required for finished compostrequired for finished compost

Open pilesOpen piles

• Slowest rate of decompositionSlowest rate of decomposition• Least expensive methodLeast expensive method• Minimal pest control and containmentMinimal pest control and containment

Holding unitsHolding units• Helps keep decomposing materials organizedHelps keep decomposing materials organized• Reduces pest problemsReduces pest problems• Requires no turningRequires no turning• Relatively slow rate of decomposition (6 Relatively slow rate of decomposition (6

months to 2 years)months to 2 years)

Turning unitsTurning units

Three-Three-chambered chambered

binbin

Barrel or Barrel or drum drum

compostercomposter

• Allow for easier mixing of materialsAllow for easier mixing of materials

• Result in a hotter pile and reduced composting Result in a hotter pile and reduced composting time (as soon as 2-3 weeks)time (as soon as 2-3 weeks)

• Usually more expensive and more labor intensiveUsually more expensive and more labor intensive

LocationLocation

• Avoid areas with drying windAvoid areas with drying wind

• Partial sun will help heat the pilePartial sun will help heat the pile

• Should be easily accessible yet not Should be easily accessible yet not interfere with yard activitiesinterfere with yard activities

• Should not be offensive to neighborsShould not be offensive to neighbors

Finished CompostFinished Compost

• Avoid using unfinished compost, organic Avoid using unfinished compost, organic acids may harm plant rootsacids may harm plant roots

• If compost is still hot, smells like If compost is still hot, smells like ammonia, orammonia, oryou can still identify much of the you can still identify much of the original organic material it is not original organic material it is not ready to use yetready to use yet

• Composting is complete when the pile stays at Composting is complete when the pile stays at or near the ambient temperatureor near the ambient temperature

• Finished compost is dark, crumbly, and has an Finished compost is dark, crumbly, and has an earthy smellearthy smell

• The volume of finished compost willThe volume of finished compost will

have been reduced by 30 to 50 percenthave been reduced by 30 to 50 percent

Finished CompostFinished Compost

Problem solving – what if?Problem solving – what if?

• The pile smells like rotten eggs?The pile smells like rotten eggs?– Not enough air/too much waterNot enough air/too much water– Add coarse material like dry leavesAdd coarse material like dry leaves– Pile should be wet like a wrung out Pile should be wet like a wrung out

spongesponge• The pile smells like ammonia?The pile smells like ammonia?

– Too much nitrogen, not enough carbonToo much nitrogen, not enough carbon– Add dry leaves, sawdust or strawAdd dry leaves, sawdust or straw

Problem solving – what if?Problem solving – what if?

• My compost pile is not heating up?My compost pile is not heating up?– Examine bin size, moisture content, air Examine bin size, moisture content, air

flow, and material ratios (C:N)flow, and material ratios (C:N)

• My compost pile is attracting pests?My compost pile is attracting pests?– Eliminate meat dairy products Eliminate meat dairy products

and fatty foods from binand fatty foods from bin– Bury food waste under a few Bury food waste under a few

inches of material like leaves and inches of material like leaves and grassgrass

Other OptionsOther Options

Have too much yard waste to backyard Have too much yard waste to backyard compost?compost?

Want to compost kitchen waste but don’t Want to compost kitchen waste but don’t have the yard space to do it?have the yard space to do it?

Here are some alternatives to backyard Here are some alternatives to backyard composting...composting...

• Municipal compostingMunicipal composting– Available though many cities and townshipsAvailable though many cities and townships– Often take larger yard trimmings (and chip Often take larger yard trimmings (and chip

them)them)– Usually offered as a free serviceUsually offered as a free service– Finished compost often available for freeFinished compost often available for free

• Contact your local county Extension Contact your local county Extension educator, county solid waste officer, or educator, county solid waste officer, or city recycling coordinator for more infocity recycling coordinator for more info

Municipal CompostingMunicipal Composting

Grass ClippingsGrass ClippingsGrass clippings are a great source of Grass clippings are a great source of nitrogen for your compost pile but nitrogen for your compost pile but usually you have more clippings then usually you have more clippings then needed. What can you do with excess needed. What can you do with excess clippings? Leave them on your lawn! clippings? Leave them on your lawn! Leaving grass clippings on lawn returns Leaving grass clippings on lawn returns nutrients to the soil (clippings will nutrients to the soil (clippings will naturally decompose).naturally decompose).

VermicompostingVermicomposting• Method of composting kitchen scraps and Method of composting kitchen scraps and

other organic materialother organic material• Materials are placed in an aerated container Materials are placed in an aerated container

with redwormswith redworms– Redworms are able to digest 2/3 their body Redworms are able to digest 2/3 their body

weight in a dayweight in a day

• Worm bins can be made out of any material Worm bins can be made out of any material that holes can be drilled intothat holes can be drilled into

CreditsCredits

• This project was developed by the This project was developed by the University of Minnesota Extension University of Minnesota Extension Service-Sherburne County and the Service-Sherburne County and the Sherburne County Master GardenersSherburne County Master Gardeners

• Funding assistance provided by the Funding assistance provided by the Sherburne County SCORE grantSherburne County SCORE grant

• Some of the graphics used were taken from the Some of the graphics used were taken from the Master Master Composter Manuel - Cornell Waste Management Composter Manuel - Cornell Waste Management InstituteInstitute

Questions?/Comments!Questions?/Comments!