Organic Gardening - Compost the Secret Recipe

2008 SOLARFESTCompost: The Secret Recipe

Wendy Sue Harper, Ph.D.Vegetable and Fruit Technical Assistance

AdvisorNortheast Organic Farming Association

of Vermont

www.nofavt.org

Questions and Answers• What do you want to get out of this talk?• Rot is Hot—but does it have to heat up?• What’s the best recipe for me?• How long have humans made compost?• Why is compost brown?• Which birds make hot compost— better than some people?• What are three things you should not compost?• How do small compost organisms get from pile to

pile?• Why does compost suppress some plant diseases,

and which ones are suppressed best?

Today’s Session• Questions• Compost through the ages• Who’s doing this for you?• Principles of Composting

– Recipes– Methods– What not to compost

• Composts value• Composts use• Questions• Resources

Compost Through the Ages • Native and ancient peoples• U.S. presidents• Albert Howard• Rodale Institute, BioCycle• NOFA’s and MOFGA’s• Towns and cities• Researchers at universities

• Farmers and gardeners have always composted.

New Farm

Richmond Then and Now

What is Compost?• Compost is the biological reduction of

organic wastes to humus. (Golueke)

Scientific American, 1991

The Brush Turkey

Mound builders are “Megapodes,” big feet, (family Megapodiidae)


What is Compost?• Compost is the biological decomposition of

organic matter under controlled aerobicconditions. In contrast, fermentation is the anaerobic decomposition of organic matter .(Epstein)

What is the Secret of Compost?

It is all about biology.

SMBDFW

Tulane Uni.

The Ecology of Compost

DFW

Think About Scale in this Watery World

• Microscopic organisms: swim in thin skins of water that coat particles in compost

• Medium size mites: walk knee-deep in water in pores

• Bigger organisms like insects and worms: make pores in compost

Microflora Swimmers: Bacteria

DFW

SMB SMB

SMB

Microflora Swimmers: Actinomycetes

SMBSMB

SMB

Microflora Swimmers: Fungi & Molds

Mold

FungiDFWSMB

SMB

SMB

University of Edinburgh

Microflora Swimmers: Fungi

Saprophytic

Parasitic

SMB

SMB

Compounds Produced:

Lignin becomes humusSMB

SMB

SMB

Fungal Phenolic Compounds

Melanin Granules

SMB

SMB

SMB

SMBSMB

Microflora Swimmers: Yeast

SMB

SMB

A Plant Virus

Plant Cell

Viruses

SMB

SMB

Microflora Swimmers: Algae

SMB

SMB

SMB

Microfauna Swimmers: Protozoa

Flagellates

Ciliates

Amoebas

DFW

DFW

SMB

Tulane University

Microfauna Swimmers: Rotifers

DFW

Microbus

Microscopy-UK

Microfauna Swimmers: Nematodes

Fungal Hyphae Nooses

Parasitized Nematode

Captured Nematodes

Interesting Relationships and Population Checks and Balances.

DFW

DFW

SMB

SMB

SMB

Mesofauna: Walk Knee-Deep in Water

Mold Mite Beetle Mite

Predatory MiteDFW

DFWDFW

Soil-USDA

More Interesting Relationships!! Phoresy: Detritivore Hitchhikers

Sucker Disc

Immature Mites

PhoreticNematodes

DFW

DFW

DFW

DFW

Mesofauna: Walk Knee-Deep in Water

Bark Lice

Spring Tails

Feathered-winged Beetle

PseudoscorpionDFW

DFW

DFW

DFW

Macrofauna: Pore Makers

Earthworms White Worms or Potworms

Millipede

DFW

DFWDFW


Ispod, Pill or Sow Bug

Slug

Land Snails Maggots or Fly LarvaeDFW

DFW

DFW

DFW


Centipede

Ground Beetle

Ants

DFW

DFW

DFW


Land Planarian, Flat Worm or Turbellaria

Wolf SpiderDFW

DFW

The Ecology of Decomposition& Soils

DFW

Principles of Composting• C:N Ratios

– Recipe• Moisture Balanced with Oxygen

– Recipe– Particle Size

• Temperature – Recipe– Size of pile– Microbes and Macrobes– Time

• Management– Assess Your Level of Interest

The Process in a Compost Pile:

• Microbial enzymatic digestion needs:• C, N, O2, H2O, Microbes, Volume for warmth,

Others?

H2O Vapor, CO2, Heat

On-Farm Composting Handbook

The Hot Composting Process

Active Phase

Curing Phase

Cornell University Waste Management Institute

Hot Compost Process Reviewed

• Stage 1: Quick digestion (1-2 days)

• Stage 2: Thermophilic digestion of cellulose (several weeks to months)

• Stage 3: Curing Phase recolonization by mesophiles (up to 4 months)

C:N Ratio• If hot compost is desired, the ratio preferred is

about 25-30:1, but 20-40:1 is acceptable.• High C materials: straw, hay, woody materials,

dried corn stalks, paper wastes.– Not are Carbon behaves the same.

• High N materials: manures, green material, food wastes.

• Start with 1 handful of N wastes to 3 of C wastes.• Cornell’s WWW site for recipe design:

– http://compost.css.cornell.edu/Composting_Homepage.htmlCornell University Waste Management Institute

What NOT to Compost• Plants diseased with a virus• Organic materials treated with toxic substances

– PT lumber wastes• Plastics• Pet wastes• Coal ash• Plants containing poisonous substances

• **Weeds gone to seed• **Diseased plants (non-virus)• **Meat, dairy, food oil

Cuke: University of Illinois Extension

Moisture Balanced with O2• If hot compost is desired, a range of 50-60% is

preferred, but 40-65% is acceptable.• Field Test: Compost should feel like a damp

sponge. Moist, but you can’t ring water out of it.• Generally, if the C:N ratio is OK, moisture is

OK. • Cornell’s WWW site for recipe design

– //http://compost.css.cornell.edu/Composting_Homepage.html

• Particle size and thus pile porosity are important too!

Proper Moisture Too Much Moisture


Getting Oxygen into the Pile:Good Porosity


Desired Recipe Characteristics:

Characteristic ReasonableRange

Preferred Range

Carbon toNitrogen Ratio

20:1-40:1 25:1-30:1

Moisture Content 40-65% 50-60%

pH 5.5-9 6.5-8.5

Oxygen Content Minimum 5%

On-Farm Compost Handbook

Temperature• Thermophilic

– over 40oC or 105oF– Destroy Weed Seeds– Destroy Pathogens– Quicker– More Management– More Labor– Less Disease

Suppression– Microorganisms:

Bacteria, and Fungi and Actinomycetes

• Mesophilic– 10- 40oC or 50-105oF– Less Management– Less labor– More Disease

Suppression– Slower– May Not Destroy

Weed Seeds and Pathogens

– Micro and Macro-Organisms Involved

SMB

SMB

SMB

Management

VS.

.

Compost a Recipe for Trouble!

Aerobic Methods

• Small piles and bins

• Windrows

• Passive aeration

On-Farm Compost Handbook

Gardener’s Easy Practical Compost Method • In bins or free standing.• Build pile by adding 1 handful

of green/wet stuff for every 3 handfuls of brown/dry stuff, added overtime.

• Add soil/old compost for odor control.

• Turn and rebuild pile in fall, mix in garden cleanup debris.

• Wait 2-3 years before using.• Do not add weeds gone to seed

or plants infected with viruses.

ORGANIC MATERIALS

ORGANIC MATERIALS - Grass, leaves, weeds, etc.

ORGANIC MATERIALS

1-2” manure

Cross Section of Layering in Compost Bin

1-2”

6-8”

SOIL

SOIL

SOIL

SOIL LINE

Troubleshooting (Summer)• Wet and stinky?

• Dry not working?

• No heat when turned?

• Add C materials and turn in sunny weather. Shape to shed water. Break up matting or compaction.

• Add N materials and turn when raining. Shape to hold water.

• Look at material if dark and crumbly with good earth smell, may be curing. No? Check size and see above.

What Composting Does for You!1. Decrease bulk of the pile (CO2 gas)2. C:N ratio3. Odor 4. Hot composting kills weed seeds & pathogens5. Cool composting provides disease suppression6. Humified (turning to humus) material is a slow

release fertilizer7. Wastes become useful material

gardener’s brown gold

Compost Improves Soil FertilitySoil Fertility is

The ability of a soil to provide a physicalphysical, chemicalchemical, and biologicalbiological environment for the plant that is health sustaining.

This is along term ecosystem based or ecological agriculture perspective!

Promote Soil Tilth with Compost• All the physical properties of soil related to plant growth

– Including: structure, drainage, aeration, moisture holding capacity, bulk density

– It aggregates soil creating structure. • And Thus:

– Drainage and aeration in clay soils (macropores) – Water holding capacity in sandy soils (micropores)– Lower bulk densities

*Cause it creates the missing pores!*Macropore hold air and drain—between soil aggregatesMicropores hold water—within soil aggregates

OM = Drought Prevention Insurance

Promote Diverse Soil Organisms with Compost

• Provides food and energy for organisms• Stimulate plant root growth• Stimulate diverse communities of

microorganisms• Suppress diseases: fungal best

SMB

SMB

SMB

Promote Soil-Plant Nutrition with Compost

• Increase Cation Exchange Capacity (CEC)• Over-time builds N, P, S & micronutrients• Chelation or complexing of metals• Help to buffer soils pH reaction

K+

Using Compost

• Mulch or top dressing• Soil amendment• Potting mix ingredient


Questions?

Useful Compost Resources• The Rodale Book of Composting

by Deborah L. Martin & Grace Gershuny. Rodale Press. 1992.

• On-Farm Composting Handbook by Robert Rynk. NRAES-54. 1992.

• Cornell’s WWW site:http://compost.css.cornell.edu/Composting_Homepage.html

• ATTRA’s WWW site:– http://attra.ncat.org/

Biological Slide References• DFW: The Decomposer Food Web: Ecology

of organisms of compost and soil litter byDr. Daniel Dindal, Professor Emertius, Soil Ecologist, SUNY-Syracuse

• SMB: Soil Microbiology and Biochemistry from Soil Science Society of America

The End

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Organic Gardening - Compost the Secret Recipe