Composting:the rotten truth
Anne KolaczykPurdue University Master Gardener2006Anne Kolaczyk
CompostingComposting is the transformation of organic material (plant matter) through decomposition into a soil-like material called compost.Invertebrates (insects and earthworms), and microorganisms (bacteria and fungi) help in this transformation.
KindsBin compostingTumbler compostingSunken pail compostingSheet compostingAnaerobic compostingVermicomposting
Bin compostingwhat most people doTumblercommercial bin that rotateswhen turned every day, produces compost in about a monthsmall sizeneed multiple tumblers or you have a stretch when you cant compostgood for kitchen waste
Sunken pailGood for kitchen waste5 gal pails with drainage holes in the bottomburied almost to top and coveredWhen full, throw some dirt in and close upBy the time you fill up a second bucket, the first should be doneSmelly when open
Sheet composting4 to 6 inches over garden in fallspade into soil in the springMulching is sheet composting at its simplestDigging holes and burying waste is sheet composting
Anaerobic compostingairless, can be done in plastic bags, smelly if bag breaksGood for small quantitiesAdd a few handfuls of dirtLeave in sun and turn every few weeks
Vermicompostingusing wormsSuperior nitrogen-rich compostSecrete calcium carbonate which regulates the soils pHEnzymes they secrete promote growth
Why do itEnvironmentally responsibleKeeps biodegradable waste out of landfills and sewage plantsAlternative to burningGives you a vibrant garden without chemical fertilizersSaves moneyLearning tool
What it involvesAdding ingredientsMaintaining proper temperatureTurningMaintaining moistureHarvesting
Some methods require fewer of these steps as the system itself handles the choreno turning is necessary with buried pail; if your bin pile is big enough, the temp will be fine.
Bin compostingbackyard composting
Composting binsReady madeHomemadeBin-less pile
Ready made ExpensiveLimited capacityGood if space is an issue
Good for small spaces
Homemade Three bins are bestOne to fillOne thats cookingOne to turn others into or to draw from
Bin-less pileJust a pile with no partitionsHard to maintain sufficient depth to achieve high enough temperaturesEasy and nothing to buildMoveable
Need a cubic yard to get interior hot enough to kill off pathogens and weed seeds.
What you can compostYard wasteKitchen scrapsNewspaperCardboard
What not to compostMeat scrapsBonesDairy productsPet wasteDiseased plantsInvasive weeds
Meat scraps and bones attract animals. Smell and can take a long time to decompose. Same with dairy products.Pet waste may carry pathogens. There is some controversy about whether pet waste can be composted safely.
Might also avoid diseased plants and invasive weeds. The temp of your pile might not be high enough to kill them off.
C:N ratioShould be 30 parts carbon to 1 part nitrogen by weightGrass Clippings19:1 Leaves 40:1Equal weight of each would give you approximately 30:1 ratio for pile
Whats whatBrown (Carbon)LeavesDirtGrocery bagsBird seed hullsWood chips
Green (Nitrogen)Grass clippingsPlant clippingsFertilizerCoffee grounds
C:N ratio, my takeWhatever!
Care of compostPassiveLet sitTakes months and monthsActiveTurn oftenKeep moist (H2O 40-60% of weight)Have proper ratio of C:N (30:1)2-6 weeks (depending on ingredients)
Lets get real
ConcernsSolutionsI dont have roomUse commercial binIt takes too long Maintain proper conditions Cut up large piecesIt smells Not if you maintain C:N ratioTemps too low to kill diseases, fungi, weed seedsUse local community composting facility for problem pieces, compost the restAttracts animalsBury food waste in center
UsesEarly stages as mulchKeeps weeds from growingHelps retain moistureBeneficial minerals go into soilLater stages for soil amendingEnriches soilHelps with moisture retentionRemoves/reduces need for chemical fertilizers that leach into our ground water
What method is right for me???
How much space do I have?Is it indoor or outdoor or both?What do I want to compost? How much waste do I have a week?How and where do I want to use the compost?How much time can I spend on it a week?Whats my ewww! factor?How committed am I to composting?
ResourcesPurdue Extension officeLibraryInternet
Just do it!
Bin compostingwhat most people doTumblercommercial bin that rotateswhen turned every day, produces compost in about a monthsmall sizeneed multiple tumblers or you have a stretch when you cant compostgood for kitchen waste
Sunken pailGood for kitchen waste5 gal pails with drainage holes in the bottomburied almost to top and coveredWhen full, throw some dirt in and close upBy the time you fill up a second bucket, the first should be doneSmelly when open
Sheet composting4 to 6 inches over garden in fallspade into soil in the springMulching is sheet composting at its simplestDigging holes and burying waste is sheet composting
Anaerobic compostingairless, can be done in plastic bags, smelly if bag breaksGood for small quantitiesAdd a few handfuls of dirtLeave in sun and turn every few weeks
Vermicompostingusing wormsSuperior nitrogen-rich compostSecrete calcium carbonate which regulates the soils pHEnzymes they secrete promote growth
Some methods require fewer of these steps as the system itself handles the choreno turning is necessary with buried pail; if your bin pile is big enough, the temp will be fine.
Good for small spaces
Need a cubic yard to get interior hot enough to kill off pathogens and weed seeds.
Meat scraps and bones attract animals. Smell and can take a long time to decompose. Same with dairy products.Pet waste may carry pathogens. There is some controversy about whether pet waste can be composted safely.
Might also avoid diseased plants and invasive weeds. The temp of your pile might not be high enough to kill them off.
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