Composting Seminar

May 15, 2008 6:30 p.m.
Akeley Methodist Church, Akeley, PA
Presented by: Penn State Master Gardeners

Why Compost?

• speeding up the natural decay process
• limited landfill space should be reserved for materials that cannot be recycled or composted
• garbage handling is the 4th largest expense for many cities - composting reduces those costs
• you need to replenish in the soil, what you take out
• PA’s goal is to recycle 35% of municipal waste
• National Compositing Council estimates the average U.S. household generates 650lb of compostables every year

Did you know: The amount of energy needed to produce 1 aluminum can can power your refrigerator for an hour.

What do you need?

• decomposers
• food for the decomposers
• the right amount of air, water, and warmth to keep them happy
• decompoers will come from the soil itself
• ‘if you build it, they will come’
• soil
• leaves
• food scraps
• manure
• finished compost

You do not need additives, starters, etc - they are strictly a money-maker for companies

What Can Be Composted

• garden trimmings
• kitchen scraps
• grass clippings
• leaves
• old potting soil
• manure
• sawdust
• hair
• wood ash (OK if used sparingly)

Do Not Compost

(attracts pests, vermins, spread disease)

• oil
• fat
• grease
• fish
• meat
• dairy
• uwashed egg shells
• cat or dog waste
• disease or insect ridden plants
• lime (increase the compost pH and promotes ammonia odor problems)
• sunflower seeds and walnuts (excuse substance to prevent things from growing)

Ammonia smell means that nitrogen is being escaped into the atmosphere

Highest temp should be 155 degrees F (to kill seeds, insects, disease plants)

Is shredding necessary?

• smaller particles decompose faster
• but also decrease airflow in the pile

What is needed

Carbon rich organic wastes are called browns
Nitrogen rich organic wastes are called greens

Browns greater than 30:1 ratio
Greens less than 30:1 ratio

Try to balance browns and greens to negate each other (make 30:1 ratio)

Too many browns

• decay very slowly
• coarse browns can keep a pile aerated
• tend to accumulate in the fall
• tie up nitrogen in soil if not full comp.
• may need to stockpile until can mix

Too many greens

• decay rapidly
• poor aeration - may have foul odors if composted alone
• tend to accumulate in spring and summer
• supply nitrogen for composting
• best composting if mixed with browns

Aerobic composting

• composting with decomposers that need air (oxygen)
• the fastest way to make high quality compost
• produces no foil odors
• aerobic decomposers produce heat
• active composting occurs in 55-155
• a thermometer is nice, but not necessary

In winter, the composter will go dormant but you can still contribute compost (spring time will revive it)

Does it have to get hot? No, but it goes slower

Lack of heat is usually:

• lack of nitrogen
• not enough air
• too much water

Pile aeration

• browns help to maintain good porosity in pile
• compacted pile has lost porosity can be increased by turning
• include big sticks

Water

• too much = loss of air in pile .. anaerobic conditions
• too little = bacterial activity will slow or cease
• pile water content should be at 40-60%
• as wet as a squeezed out sponge
• if too dry, add water as you turn pile
• if too wet, add browns and or turn the pile

When pile no longer heats after mixing, allow it to cure (stand without mixing) for at least 4 weeks before using the compost

Cover finished compost - don’t want rain washing out all the nutrients

To make it fast

• turn pile ever 5-7 days
• during first few weeks temp should reach 140
• after 4 weeks, less heat will be produced and compost will maintain lower temp (100 degrees)
• after 4 more weeks pile will no longer heat after turning and volume will be about one third of original
• allow to cure for 4 more weeks

When is compost finished?

• color is dark brown
• is crumbly, loose, and humus-like
• has an earthy smell
• contains no readily recognizeable feedstock
• pile has shrunk to about 1/3 of its original volume

Compost is not a fertilizer
It is an amendment

Simple tests for finished compost

Bag test

Sealing compost in a plastic bag for several days should produce no foul odor

Germination test

Will seeds germinate in it?

Where should I put my compost pile?

• Where it is convenient
• good drainage
• away from any wells

Ideal size is approximately a 3 foot cube

Troubleshooting

Rotton odor

• putrid smell or rotten egg small
• usually results from anaerobic = excess moisture, compaction
• Fix: turn pile

Ammonia odor

• too much nitrogen (Greens)
• Fix: add high carbon browns and turn

Low pile temp

• pile is too small
• cold weather
• too dry
• poor aeration
• lacks nitrogen
• make pile bigger or insulate sides
• add water
• turn the pile add greens and turn pile

Benefits of Composting

• supplies organic matter to soil
• attracts earthworms (what goes into a worm comes out 10x better)
• stimulates beneficial microorganisms
• increase soil water hold capacity
• increases soil nutrient retention
• with heavy metals and contaminated soil, compost keeps plants from absorbing those harmful things
• compost will pH balance the soil
• improves soil tilth and friability
• improves solid drainage
• loosens heavy clay soils
• suppresses soil-borne plant pathogens (diseases)
• nitrogen and phosphorus are mostly in organic forms
• released slowly to plants
• not readily leached from the topsoil

Using compost

• as a soil amendment
• be sure that compost is mature
• aslawn top dressing
• as potting mix (no more than 1/3 compost by volume)

Using unfinished compost

Surface mulch

• max 3” depth
• start 3-4” from trunk
• extend out to dripline
• do not use fresh wood chips - it will strip nitrogen out of soil to decompose

Recommended Books

• The Rodale Book of Composting: Easy Methods for Every Gardener
• Gardener’s Guide to Better Soil

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