How to

How to Make Compost

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

Read more about, Why you should compost

By turning food scraps and organic garden waste into compost you can:
• Improving soil quality and garden vitality by releasing rich nutrients into the soil.
• Suppressing plant diseases and pests, this reduces or eliminates the need for chemical fertilisers and manures helping you save money.
• Reducing the amount of organic waste going to landfill therefore preventing greenhouse gas emissions and leachate which can pollute land, groundwater and waterways.
• Helping soils retain moisture – you do not need to water that often.
• Helping absorb and filter runoff, protecting streams from erosion and pollution.

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.

Balance of ingredients

Good compost is produced by blending leafy ‘green’ matter with harder ‘brown’ matter. ‘Green’ matter includes grass clippings, vegetable scraps, and soft green prunings. ‘Brown’ matter is shredded woody branches, dried leaves, straw and shredded newspaper.

Try to add brown and green matter in layers, not making any layer too thick. If you put in too much green matter, the compost may go sludgy and smelly. Too much brown matter and it won’t break down quickly. With a good balance of the two, composting will proceed quickly.

Composting organisms require four equally important components to work effectively:

1. 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.

2. 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.

3. 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.

4. 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.

What to add to a Compost Heap

• Vegetable and food scraps
• Fallen leaves (in layers)
• Dead flowers
• Weeds
• Grass cuttings in layers
• Coffee grounds
• Tea leaves and tea bags
• Soft stems
• Old potting mix
• Egg shells
• Old newspapers (wet)
• Used vegetable cooking oil
• Sawdust (not from treated timber)

What not to add to a Compost Heap

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

How to start your Compost Heap

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:

See the list above and remember 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.

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. If your composting is unsuccessful, consult the checklist in Yates Garden Guide.


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