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.

Choose a location. The compost heap/bin should be placed directly onto the soil in a sunny position.
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.
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.
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

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