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CompostingCompostingBill DeKramer

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What is Compost? What is Compost?

Nature recycles organic matter (OM) in place

Composting is a man-made system to recycle OM more quickly and efficiently

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Topics for tonightTopics for tonight

Compost and soil structure / valueElements of a compost pileWhat makes compost work - the bugs

involvedTypes of compostingBuilding some models

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A Compost pile is not a garbage pile

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Compost and soil structureCompost and soil structure

Structural components of soil– Sand– Silt – Clay

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What ratios would you like in What ratios would you like in your garden?your garden?Medium Loam:

– 20% clay– 40% sand– 40% silt

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Benefits of compost to the soilBenefits of compost to the soil

Organic Matter (OM)Microbes

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What is Organic Matter?What is Organic Matter?

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Organic MatterOrganic Matter

Food for soil food web microbesHumus (not hummus)

– OM that has reached a point of stability, i.e. won’t break down any more

– Humus is a colloidal substance, and increases the soil's cation exchange capacity, hence its ability to store nutrients by chelation.

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What Microbes are in Compost?What Microbes are in Compost?

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MicrobesMicrobes

BacteriaFungiAmoebas, slime molds, multi-celled algaeNematodes Bugs

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Essential Elements for CompostEssential Elements for Compost

CarbonNitrogenOxygenWater

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Elements to Control in Elements to Control in CompostCompostFood stock: Carbon and NitrogenMoistureAirTemperatureParticle SizepH

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Food stockFood stock

Carbon sources:– Hay and Straw– Leaves– Black and white newspaper– Sawdust and Wood chips

Nitrogen sources– Kitchen scraps– Weeds (without seed heads)– Animal manure (except dog, cat, pig or human)

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What not to addWhat not to add

Kitchen scraps like meats, oils, fish, dairy products, and bones

Weeds that have gone to seed or spread by their roots (quack grass, etc.)

Herbicide treated grass clippings or weedsDog, cat, pig or human faeces

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Carbon / Nitrogen ratioCarbon / Nitrogen ratio

Having the right carbon / nitrogen ration makes a difference in how quickly the food stock breaks down.

Ideal is 25 : 1 carbon to nitrogen

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Common Compost MaterialsCommon Compost Materials

Kitchen / Table scraps 15:1Grass clippings 12:1Old manure 20:1Fruit waste 25:1Corn stalks 60:1Old leaves and straw 80:1Paper 170:1Sawdust and wood chips 500:1

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Prohibited for Organic Prohibited for Organic ProductionProduction Prohibited

– Sewage sludge– Glossy paper and coloured ink– Paraffin from waxed cardboard (not to exceed .75%)

Regulated– Slaughterhouse, hatchery, fish-farm waste– Yeast fermentation waste– Whey– Mushroom compost

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MoistureMoisture

Ideal is about 50%Rule of thumb: like a wrung out spongeThe amount of moisture determines if the

pile is aerobic or anaerobic

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AirAir

There are 2 types of compost piles– Aerobic– Anaerobic (Bokashi)

If an aerobic bin gets too wet, it can become anaerobic and create toxins

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TemperatureTemperature

Hot CompostCool Compost

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Hot Compost Hot Compost (50º-75º C)(50º-75º C)

Relies more on aerobic bacteriaMakes compost quicklyCan kills pathogens and weedsRequires frequent turningRequires attention to brown/green ratioVery fertile, but not as fertile as cool

compost

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Cool Compost Cool Compost (25º-50º C)(25º-50º C)

Low maintenanceCan be built (layered) over timeTakes longer to finish than hot compostDoesn’t kill pathogens or weeds

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Particle SizeParticle Size

The smaller the particle, the quicker it decomposes

For example, grated apples break down faster than whole apples

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pHpH

Ideal pH is around 7 (neutral)Usually don’t need to worry about pH if

including a wide variety of food stocks, but some things like an excess of coffee grounds can make the pile acidic.

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Types of CompostingTypes of Composting

LayeredWorm (vermiculture)BokashiSheet composting

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Building a layerBuilding a layer

When starting a new pile, lay some twigs in the bottom to help keep air in

Alternate layers of brown and green Sprinkle a handful or shovel full of soil or

compost in with the layers as inoculate Finish with a layer of brown material that acts

like a “scab” – Up to half the carbon and nitrogen can be lost to the

atmosphere if exposed to the sun and air. When starting a future set of layers, pull the

scab back to allow the materials to be in contact

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Layered CompostLayered Compost

This is the most common form of composting Layered composting is an evolution of

the Indore method that focused on the carbon/nitrogen ratios and moisture.

Layers of brown and green material are alternated

Batch method is when the layers of the whole pile are built in one go. This is usually for the hot method

Continuous method is when layers of the pile are built periodically as the materials come available. This is usually for the cool method.

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Demonstration pileDemonstration pile

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Composting in WinterComposting in Winter

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Screens for Finished CompostScreens for Finished Compost

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Worm Composting Worm Composting (vermiculture)(vermiculture)

Composts food waste rapidlyBin needs to stay between 12º - 25º CNeeds a moist environment (worms

breathe through their skin)Worms need oxygen and produce CO2

pH around 7 but can tolerate 4.2 - 8.0Bedding can be cardboard, shredded

paper, decaying leaves or peat moss

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Worm CastingsWorm Castings

Worm castings are very rich– Produce plant-available nutrients– Wide variety of microbes inoculating the rest

of the compost pileWorms can produce their weight in

castings every 24 hours

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Storing the Worm BinStoring the Worm Bin

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The WormsThe Worms

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Feeding the WormsFeeding the Worms

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Demonstration Demonstration

Building a Worm Bin

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Bokashi Bokashi

Bokashi is a Japanese term meaning 'fermented organic matter'

Bokashi is anaerobic composting utilizing a starter to inoculate the pile with specific organisms (facultative anaerobes)

Quick way to compost food scraps Carbon / Nitrogen ratio is much less important Microbes that grow in bokashi are very different

from aerobic compost so it adds diversity to the soil food web

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Facultative AnaerobesFacultative Anaerobes

Facultative anaerobes are organisms that can be simultaneously aerobic and anaerobic

They adapt to the oxygen level of their environment

When low oxygen they switch to their fermenting metabolism, which utilizes enzymes to break down food.

Fermentation only partially breaks down the food so it needs to be finished by other microbes

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Sheet CompostingSheet Composting

Sheet composting is a method of building a garden bed by creating a compost “pile” as the bed itself

Sheet composting is designed to mimic the natural processes that occur in forests.  You build it right on top of grass or weeds so all the natural organic matter that's already there and the microbial populations don't get hauled away with stripping off the sod or weeds.

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Layers in a Sheet CompostLayers in a Sheet Compost

Cover the area with cardboard or newspaper and water it in well

To accelerate the decomposition of the grass and cardboard, put a thin layer of manure down under the cardboard

Cover the cardboard or newspaper with organic matter like compost, peat moss, straw, or leaves and water this well so it's like a damp sponge.

Plant it.  Wherever you want to put a plant, push the straw and leaves away a bit, add a little soil and compost and put the plant in it.

This is covered more in Building a Garden Bed

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QuizQuiz

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SummarySummary

What are the most important points about composting?

Why would you want to compost?How will you apply this information?

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2nd Summary2nd Summary

Composting is one of the most effective ways to improve your soil and the soil food web

There are many ways to create compost. The most important way is your way, the way that fits your time and lifestyle

“Just do it!”

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