Composting food and garden materials

Composting is a free and simple process that you can do at home. Garden waste and your fruit and vegetable scraps can all be composted to improve the soil in your gardens and pots. There is a composting method to suit your lifestyle.

Watch the video: Living Greener.

Rethink waste fact sheets:

Ingredients

Compost is the soil-like organic material that is created when plant and vegetable matter breaks down and is rich in microorganisms and nutrients. It can be used as a potting mix, soil conditioner, or simply as a natural fertiliser.

This table includes organic materials that can be composted, some of which are not good for worm farms. More information is available under Methods.

The first column list compost types. The second column lists each ingredient grouped by type.

 Type Ingredients 

Nitrogen products ('greens')
  • Fruit
  • Vegetables
  • Coffee grounds
  • Tea bags (avoid the plastic mesh bags used for some specialty teas)
  • Fresh grass clippings (in smaller amounts)

Carbon products ('browns')
  • Dried leaves 
  • Dried grass clippings (preferable)
  • Mulch and straw
  • Paper towel
  • Newspaper (not the glossy pages)
  • Cardboard
  • Shredded paper
  • Toothpicks and timber skewers
  • Twigs and sticks (thin and broken up only)
  • Vacuum cleaner bag contents

Do not add the following ingredients to compost:

  • dairy products
  • pet faeces (e.g. cats and dogs)
  • meat scraps and bones
  • weeds
  • plants that are diseased or have been sprayed with pesticides
  • plastic
  • treated timber
  • vegetable fats and oils.

Methods

There are a few different composting methods you can use. The best one for you depends on your lifestyle, the size of your property, the amount of kitchen/garden waste your household produces, and how much time and money you want to spend looking after a compost system.

The first column identifies different compost methods, with images to clarify. The second column details the different ingredients usable within each compost methods. The third column includes general notes relating to each method of compost.

Compost method Ingredients  Notes 
Heap 
Compost heap with shovel sticking out
 Garden waste only  Pile lawn clippings and prunings in a heap. Turn regularly to speed up breakdown of garden waste. 

Compost bin

Black compost bin with indented pattern around the bin
 Garden waste and food scraps 
  • Works well for people with a backyard.
  • Will take longer to break down into compost. Larger food and garden pieces are acceptable. 

Compost barrel or tumbler

Green compost barrel with a silver A frame holding it off the ground on an angle.
Garden waste and food scraps 
  • Chop or cut food and garden material into much smaller pieces - to break down quicker.
  • Requires regular rotation.
  • Do not fill the tumbler as they are heavy to tumble, and parts may break. 

Worm farm

Black circular raised worm farm with 5 black legs
 Garden waste and food scraps 
  • Suitable for small spaces e.g. balcony or garage
  • No pet faeces, especially if recently wormed
  • No acidic foods e.g. onions, chilli, citrus
  • Use the worm liquid as a diluted fertiliser (1:10)

Solving problems

The first column includes a range of possible issues that could occur when attempting to compost. The second column identifies possible causes for each of the problems. The third column contains possible solutions to each problem and cause.

Problem  Cause  Solution 
Compost smells Compost is too wet 
  • Add more carbon material (browns) to dry the compost material.
  • Mix in lime or dolomite to bring the acid mixture back to a neutral pH level.
Not enough air
  • Turn the pile more regularly to improve drainage and aeration.
  • Add coarse material (e.g. twigs) to create air pockets.
  • Stand a pipe with air holes or slits in the centre of the compost bin to increase the air flow through the centre of the material.  
Slow to break down Not enough 'active' ingredients  Add more 'active' ingredients to compost mix, i.e. comfrey leaves, food waste, livestock or chicken manure. 
Not enough air  Turn more regularly 
Compost too dry Add more water until compost is damp all the way through 
Pieces too large
  • Broccoli or corn stalks, apple cores, citrus skins, eggshells, twigs and prunings can take longer to compost. Use an old blender or food processor to reduce food particles.
  • Cut, break, mow or mulch garden waste into smaller particles. 
Maggots or cockroaches
(both maggots and cockroaches are beneficial to the breakdown process, so if you can tolerate them, they will help your materials to break down faster)		 Ingredients such as meat or fats added to bin
  • Avoid adding meats or fats to bin.
  • Cover maggots with garden lime.
  • Cover each layer of food waste with carbon materials.
  • Turn more regularly to mix fresh scraps with already composted material.
Mice and rats Excess bread or grains 
  • Turn heap more regularly to ‘disturb’ their environment.
  • Cover each layer of food waste with carbon materials.
  • Put fine wire mesh under the bin/heap.
Compost is too dry
  • Add more water until heap is damp all the way through.
  • Leave the lid open during a rain shower.
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