Composting:
the rotten truth
Anne Kolaczyk
Purdue University Master Gardener
©2006Anne Kolaczyk
Composting
Composting 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.
Kinds
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Bin composting
Tumbler composting
Sunken pail composting
Sheet composting
Anaerobic composting
Vermicomposting
Why do it
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Environmentally responsible
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Keeps biodegradable waste out of
landfills and sewage plants
Alternative to burning
Gives you a vibrant garden
without chemical fertilizers
Saves money
Learning tool
What it involves
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Adding ingredients
Maintaining proper temperature
Turning
Maintaining moisture
Harvesting
Bin composting
“backyard composting”
Composting bins
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Ready made
Homemade
Bin-less pile
Ready made
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Expensive
Limited capacity
Good if space is an
issue
Homemade
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Three bins are best
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One to fill
One that’s “cooking”
One to turn others into or to draw from
Bin-less pile
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Just a pile with no partitions
Hard to maintain sufficient depth to
achieve high enough temperatures
Easy and nothing to build
Moveable
What you can compost
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Yard waste
Kitchen scraps
Newspaper
Cardboard
What not to compost
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Meat scraps
Bones
Dairy products
Pet waste
Diseased plants
Invasive weeds
C:N ratio
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Should be 30 parts carbon to 1 part
nitrogen by weight
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Grass Clippings 19:1
Leaves 40:1
Equal weight of each would give you
approximately 30:1 ratio for pile
What’s what
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Brown (Carbon)
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Leaves
Dirt
Grocery bags
Bird seed hulls
Wood chips
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Green (Nitrogen)
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Grass clippings
Plant clippings
Fertilizer
Coffee grounds
C:N ratio, my take
Whatever!
Care of compost
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Passive
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Let sit
Takes months and months
Active
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Turn often
Keep moist (H2O 40-60% of weight)
Have proper ratio of C:N (30:1)
2-6 weeks (depending on ingredients)
Let’s get real
Concerns
I don’t have room
Solutions
Use commercial bin
It takes too long
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It smells
Not if you maintain C:N ratio
Temps too low to kill
diseases, fungi, weed seeds
Use local community composting
facility for problem pieces,
compost the rest
Attracts animals
Bury food waste in center
Maintain proper conditions
 Cut up large pieces
Uses
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Early stages as mulch
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Later stages for soil amending
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Keeps weeds from growing
Helps retain moisture
Beneficial minerals go into soil
Enriches soil
Helps with moisture retention
Removes/reduces need for chemical
fertilizers that leach into our ground water
What method is right for me???
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How much space do I have?
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What do I want to compost?
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Is it indoor or outdoor or both?
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?
What’s my ewww! factor?
How committed am I to composting?
Resources
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Purdue Extension office
Library
Internet
Bin
Anaerobic
Tumbler
Just do it!
composting
Vermi
Pail
Sheet