Home composting

What is composting?

Composting is the rapid breakdown and decomposition of organic material such as food scraps and garden organics. Appropriate moisture content, oxygen and heat are required for the composting process to occur. Under these conditions micro-organisms break down the organic matter into a nutrient rich soil-like product which can be utilised by plants. The composting process helps to decrease the amount of organic material disposed of to landfill. Organic material decomposing in landfill creates harmful greenhouse gases. Creating a composted product therefore prevents generation of these harmful emissions whilst enriching Perth's sandy soils.

There are various ways of composting, including the covered compost heap, a compost bin and a compost tumbler, and by worm farming. There are different principals to consider in the choice of each method, however, the main considerations are the purpose, size and type of your garden.

How does composting occur?

Micro-organisms are the major factor involved in the composting process. Bacteria, unable to live in high temperatures, start off the process by breaking down the readily available organic material. This initial process generates heat, causing the temperature in the compost pile to rise. A different type of bacteria take over and continues to convert organic material into a soil-like substance (called humus). More heat is generated by these bacteria increasing the temperature within the compost mass.

The temperature increase helps to kill weed seeds, and other pathogens that can cause harm to human and environmental health. Once most of the degradable organic matter has been broken down, the temperature starts to decrease within the compost. Decomposition will continue but at a much slower rate. This process takes approximately 12 weeks. Once the temperature has fallen to that of ambient air, the maturation stage occurs. The compost is then left undisturbed for about 30 days to fully mature.

How to compost at home?

Composting is a process that can easily be performed at home. The following steps show how easy it is to create your own compost bin or heap.

  1. Choose a location. The compost heap/bin should be placed directly onto the soil in a sunny position.
  2. Starting materials. It is best to start your compost bin with 'brown' material, which consists of dried leaves and shredded garden organics. These materials decompose slowly and have low moisture levels. Place alternative layers of 'green' materials, which consist of food scraps or grass clippings. Add some water it the compost material is too dry.
  3. Maintenance. Keep your compost heap/bin moist but not too wet (the consistency of a wet wrung out sponge). Adding food scraps to the centre of the heap/bin will help keep pests away and allow decomposition to occur more rapidly as the highest temperature point is in the middle of the compost. To increase aeration within the compost, turn the material at least once a week.
  4. When to use: Compost should be ready to use in three to six months. Dampen and lift the compacted compost with a garden fork to separate into a crumby texture.
     

Troubleshooting with home composting

PROBLEM

CAUSES

SOLUTION

Compost taking too long to break down

Too dry

Add water

 

Not the right mix

Add equal amounts of vegetable scraps or fresh lawn clippings (greens), with fallen leaves or straw (browns)

 

Not enough air

Turn more, add more compost worms, punch holes in your bin, add in some piping to help airation

Smelly compost

Too wet
To acidic
Insufficient air
 

See below
Add wood ash or dolomite to neutralise the heap
Turn more regularly
 

Flies

Open organic matter
Meat or dairy products
 

Cover organic waste with a layer of soil
Avoid putting meat or dairy products in the compost mix
 

Too wet

Too much water has been added
Organic waste is too moist
 

Improve drainage under the heap
Mix in some dry 'brown' materials or shredded newspaper
 

Pests or rodents

Attracted to uncovered food or warmth

Cover each organic layer with soil and place the bin on a layer of fine mesh

A large number of slaters and ants

Heap is too dry

Add water or moist materials

Spiders under the lid

Attracted by the flies

Place handle on the lid
Check for spiders
Cover each organic layer with soil
 

What can and can't be composted

There are a lot of materials within the home that can be composted, however there are some materials which are not suitable.

WHAT CAN BE COMPOSTED

WHAT CANNOT BE COMPOSTED

Green organic materials

There are many organic waste items that may
encourage vermin such as rats, flies and cockroaches,
and will smell when they decompose.
 

  • Leaves (Green prunings)
  • Grass (Green clippings)
  • Food scraps
  • Coffee grounds
  • Tea bags
  • Hair from your brush & comb
  • Seaweed
     
  • Fats and oils
  • Meat products
  • Dairy products
  • Cat or dog faeces
  • Plastics, steel, aluminium and glass
     

Brown organic materials

  • Dried leaves & dried grass clippings
  • Sawdust (not treated pine)
  • Wood shavings (not treated pine)
  • Hay and straw
  • Vacuum cleaner dust
  • Shredded paper
  • Newspaper
  • Egg shells
     
 

Download brochures from your local council on composting and wormfarming

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