Let it Rot - Keys to Effective Composting

Eﬀective
Composting
Independence Gardens
Portland, OR
Download the handout
that goes along with
this slideshow!
http://bit.ly/AyRFHp
January 2012
© Independence Gardens LLC
Tuesday, January 31, 2012

Topics We’ll Cover
• What is composting?
• Why compost?
• Composting methods
• How to make compost…
eﬀectively
• Harvesting/using compost
• Vermi- intro
• Questions and hands-on
practice
What We’ll Cover TodayPreview
Got Questions?
Please ask as we go along.

What We’ll Skip Today
• The process by which
organic materials such as
grass clippings, leaves, and
food waste are broken
down and decomposed
• A strategy for recycling
organic (living/no longer
living) matter into a useful
and necessary soil
ingredient
And Some Other OptionsWhat is composting?

Why Compost?
• Food & paper are the two
largest contributors to landfills
- More than 1/2 of all landfill waste
- More than all plastics, diapers,
styrofoam, and tires COMBINED
• Food is the #1 least recycled
waste product
- NOT taking into account the food
that goes down sink disposals
• But composting food waste and
paper is easy, and FUN!
Why compost?

Columbia Ridge Landfill 137 miles
When stuﬀ goes “away”…
The Metro region
landfills 270,500 tons of
food and non-recoverable
paper per year: 21% of
the waste stream

• It does not (have to)
- Involve chemicals, huge amounts of
power, or transportation
• It does…
- Offer “closed loop” sustainability
• From table to compost to garden to table
- Reduce landfill waste & runoff
- Help your plants survive drought
- Discourage pests
- Encourage microbial life in soil
- Act as a healthy soil amendment
• Improve tilth
• Offer steady release of nutrients
What does compost do?

Backyard composting methods
• Hot/fast
• Cold/slow
• Pile
• Trench
• Pit
• Container
- Ex: 3-bin systems
- Ex: Earth Machines (a.k.a.
Darth Vader hats)

• Sheet mulching
- a.k.a. “lasagna gardening”
- Slow; use to prep beds for later planting
• Vermicomposting
- Red wriggler WORMS!
- Slow method that breaks food waste down
into “black gold”
• Commercial
- Hot/fast: don’t try this at home
- Can break down a wider variety of
materials than backyard scale
Other composting methods

• Ingredients/recipe
- 3 parts “brown”
- 1 part “green”
• Particle size
• Moisture
• Air
• Temperature
• Turning the pile
• Duration
Compost considerations
BROWN (C)
1
BROWN (C)
1
GREEN (N)
1
BROWN (C)
1

• “Browns” (Carbon)
– Examples:
• Brown leaves
• Dry grass
• Straw
• Small sticks
• “Greens” (Nitrogen)
– Examples:
• Food Waste
• Manures
– From herbivores!
• Green grass
Remember the Recipe….3 parts brown to 1 part green
Ingredients/recipe

GREENS
- fruit & vegetable scraps
- coﬀee grounds
- rice & pasta
- eggshells
- tea bags
- flowers
- plant trimmings
- hedge clippings and other
fresh yard debris
- fresh grass (small
amounts)
- animal manures (e.g.
chicken, rabbit, goat,
horse, cow, alpaca)
- seaweed/kelp
Compost: YES
BROWNS
- coﬀee filters
- stale bread
- houseplant cuttings
- paper napkins & towels
- dryer lint (mostly cotton)
- hair (yours/your pets’)
- clean cardboard/paper
- wood ash (NOT Duraflame/
Presto logs!)
- leaves
- straw or hay
- small twigs/chips
- dried grass & weeds
- cotton rags
- animal bedding (sawdust)

MEAT
- chicken, beef, fish
- bones
- fat
DAIRY
- milk
- yogurt
- cheese
Compost: NO
PLASTIC
- bags
- straws
- juice boxes
METAL
- wrappers
- aluminum foil

• Smaller is better!
• Chop it up!
• Bury food in pile!
Particle size

• Damp enough to leave hands
moist (like a wrung-out
sponge)
– Often becomes not the case in the
fall / winter/ spring
• When squeezed, water
should not drip out
Best Practice:
TARP IT!
Covering your pile
retains...
• Heat
• Appropriate nutrients
• Moisture content
The Monsoon
Continues!Moisture

• Aerobic microbes are
good
– Breathe in oxygen
– Release CO2
• Anaerobic microbes are
smelly!
– Release methane
Air

• Hot pile = good pile
– 140°F for 3 days to kill
pathogens and weed
seeds
Temperature
Best Practice:
USE A COMPOST
THERMOMETER
• Allows you to measure
temps accurately

• Makes food more
available for microbes
• Aerates the pile
• Keeps the pile hot
• Make sure you turn all of
the pile
• Yes, you can turn in
all seasons
Turning the pile

• Turn until pile stops
warming up…
- Food is gone, so microbes
dead/dormant/less active
• Average backyard
compost pile is finished
in 4-6 months
• Other methods can be
faster or slower
Duration

• Much slower composting
method than pile or
trench
- Give yourself 6 months to 1
year for a whole area to be
plantable
• But it’s more flexible
- You can compost in place
around existing plants
• Step-by-step…
Sheet mulching basics

1. Mow down existing grass/plants and remove invasives
2. Add a 2” N layer (grass clippings, manure, kelp, cottonseed
meal, fish product, urine, coﬀee grounds, kitchen scraps)
3. Aerate soil with a digging fork & water
4. Lay down a C weed barrier (cardboard or 10ish layers oﬀ
newspaper)
5. Add ~ ½” N layer
6. Repeat steps 4 (with any C source) & 5 to desired thickness
7. Water well
8. Add a 12” blanket C layer (straw, leaves, wood chips,
shredded paper)
Sheet mulching how-to

Harvesting Compost
• When pile is cooled,
compost is ready to use
- Can be tarped and stored for
6-12 months
• Screening
- Use chicken wire or hardware
cloth in wooden frame
- “Overs” can be used to start
new compost pile
• Curing
- Letting finished compost sit
for 2-3 months will make it
darker, more stable nutrients
Harvesting

• Fertilizer
- Mix compost into soil
around plants
• Potting Soil
- 1 Shovel compost
- 1 Shovel good black soil
- ½ Shovel perlite
- 1 Shovel sand
• Topsoil
- 1 Shovel compost
- 1 Shovel sand
Recipes

• Compost “halo”
- Good fertilization method
- Lay a ring of compost on
ground around plant stems
- Cover with soil
• Planting with compost
- Mix with dark surface soil
- Put at bottom of planting
hole
- Plant!
Recipes

• Know your habits
- How much kitchen/yard
waste do you produce?
- How will you collect
scraps? (countertop unit,
fridge or freezer...)
- How much time/desire do
you have to tend?
- Do you have household/
neighborhood buy-in?
- Could you share the work?
And then there is you...

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Let it Rot - Keys to Effective Composting

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