What is Composting?

View our Composting Fact Sheet (57.69kb)

Making your own garden compost is a lot easier than most people realise. With a simple heap you can recycle most of your organic household and garden waste and enrich your garden’s soil at the same time. It’s also an extremely satisfying way to help the environment.

By turning food scraps and organic garden waste into compost you can:

• Improve soil quality and garden vitality by releasing the rich nutrients in the compost into the soil of your garden
• Prevent greenhouse gas emissions by encouraging the aerobic breakdown of organic material and reduces the amount of garden and kitchen waste going to Landfill
• Recycle valuable nutrients and reduce the use of artificial fertilisers
• Saves you money

A composting system confines the organic material and often controls the conditions in the material so that the breakdown is accelerated. A composting system can be started in old garbage bins, wooden boxes, or in a simple heap.

Composting organisms require four equally important components to work effectively:

Nitrogen (Green ingredients): supply your pile with nitrogen which grow and reproduce organisms to oxidise the carbon.  These additions are often green and wet: kitchen scraps, fresh lawn clippings, weeds pulled from your garden.  Every pile needs the green ingredients, but if all you have is green stuff, your pile can turn stinky and mucky.  Too much green stuff can lead to a rotting pile instead of a composting pile.

Carbon: (Brown ingredients): supply your pile with carbon for energy (heat).  These items are often brown and drier--fall leaves, branches, hedge clippings, straw, etc.  The carbon is very necessary but again, too much has its consequences.  If you have a pile with mostly prunings from your hedge and other woody stuff, the pile can take years to break down.  It can sit there and linger in your back yard and you may begin to make plans to will your compost to your grandchildren.

Oxygen, for oxidizing the carbon, facilitating the decomposition process. Done by regularly turning the mixture.
Hint: If your compost becomes starved of oxygen, then it starts to produce greenhouse gases - so it's important to get air into your compost heap, for example by turning it regularly.

Water: mixture should be moist, but not soaking wet to maintain activity without causing anaerobic conditions

Hint: Make sure your material is cut into a small particle size as smaller particles break down more rapidly

Finally, the addition of some soil will encourage the introduction of composting microorganisms which facilitate the breakdown of the material.

Your Four Step Guide to Creating Great Compost

1. Choose a Site: Place your compost heap or bin in a well-drained area that has some shade. Too much sun will dry out your compost.

2. What to Compost:

• Green Ingredients: Compost needs a mixture of nitrogen rich organic materials such as fruit and vegetable peelings, and green garden vegetation such as fresh grass clippings and green leaves.
• Brown Ingredients: Nitrogen-poor, carbon rich materials such as dry leaves, woody twigs, paper and straw.
• Water
• Some soil or completed compost to introduce composting micro-organisms

3. Layering: Start with a thick layer of coarse material (~15cm), such as twigs or mulch, this is used for drainage. Then follow with a layered A,B,C system using the materials above A. Garden clippings and kitchen scraps, B. Dry leaves and paper (wet). C. Add water after each layer to keep the heap moist but not wet. Then repeat steps ABC. Finish with step D. Sprinkling soil or finished compost on top of food scraps will make a richer compost and help reduce odours.

4. Maintaining Your Compost: Keep your compost well aerated to prevent foul odours or methane. Turn your compost with a garden fork on a weeky basis. Otherwise place garden stakes or pipes through the heap to allow air in.

Depending on the mix of ingredients the duration for the compost to turn into a rich soil can be anything from 6 weeks to 6 months.

Hint: Cover your heap so that it is just moist, not wet. If it is wet or saturated mix more dry brown material through it and turn.
Hint: If you wish, add compost accelerator (young nettles are an excellent natural accelerator) to help speed up the composting process.

What to add to a Compost Heap

• Vegetable and food scraps
• Fallen leaves (in layers)
• Tea leaves and tea bags
• Coffee grounds
• Vacuum cleaner dust
• Soft stems
• Dead flowers
• Old potting mix
  
• Used vegetable cooking oil
• Egg shells
• Old newspapers (wet)
• Grass cuttings in layers
• Weeds
  
• Sawdust (not from teated timber)
• Wood ash
• Human and animal hair
  

What not to add to a Compost Heap

• Meat and dairy products
• Diseased plants
• Metals, plastic, glass
• Animal manures (especially the droppings of cats and dogs)
• Fat
• Magazines
• Large branches
• Weeds that have seeds or underground stems
• Bread or cake (may attract mice)
• Bones
• Sawdust from treated timber
  

Interesting facts

• About half of what we throw into the garbage bin is food and garden vegetation.
• Compost bins and worm farms are available from some local councils.
• Anything that’s sharp or thorny should also be left out, because although the compost heap will destroy the thorns, you’re likely to scratch yourself later on, risking a trip for a tetanus injection.
• Did you know that increasingly more and more local councils are introducing organic recycling services to reduce the amount of organic waste going to landfill. Check whether your local council have a scheme and if they don’t ask them to introduce one.

Troubleshooting Composting

Smelly Compost: If it gets too wet or if there is not enough air in the heap your compost can smell. A common cause is having too much food and not enough dry ingredients in your compost.
How to fix it:

• Fork in dry leaves or garden mulch.
• Add garden lime, dolomite or woodfire ash to the heap to reduce acidity.
• Turn the compost to add air.
• Combine nitrogen-rich ingredients with sawdust or shredded newspaper before adding to the heap.
• Give your compost heap a ‘floor’ of planks to ensure good drainage.

Pests/ Vermin: Cockroaches, mice or rats can sometimes make your compost their home.
How to fix it:

• Always cover food with a layer of garden vegetation or soil – then cover heap  with underfelt, hessian or polythene plastic sheet.
• Turn the compost to discourage habitation.
• Fine wire under the compost bin or heap helps keep out mice and rats.
• Avoid placing dairy products, meat and seafood in the compost.

Compost Slow to Mature: A slow composting system can mean that the compost is not hot enough, or there may not be enough air or water.
How to fix it:

• Add nitrogen-rich material, such as kitchen scraps or green garden vegetation.
• Turn the heap and add water.
• Cover the compost with insulating material in winter if it gets too cold.

Composting Links

• International Composting Awareness Week website which can be found at: http://www.compostweek.com.au/ and do your bit for the environment.
• BBC Bloom website: http://www.bbc.co.uk/bloom/actions/composting.shtml

View our Composting Fact Sheet (57.69kb)