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Composting and Worm Farms

Did you know that nearly half of what we throw into our general waste bin can be made into compost and mulch?

Organic materials such as garden waste and food scraps are a valuable resource that can be used to improve our gardens.

In the City of Mitcham you have three options for disposing of organic material:

What is Compost?

Composting is a natural process where organic material (food and garden waste) is broken down by micro-organisms over a period of time. The final product is referred to as humus and is dark in colour, crumbly and has a pleasant earthy-smell.

Benefits of Composting

Composting is an easy, inexpensive and efficient way of recycling in your own backyard and has many benefits including:

  • Creating healthy gardens by adding valuable nutrients, enhancing the water-holding capacity of soil and reducing water loss through evaporation.
  • Reducing plant stress during summer.
  • Reducing soil erosion.
  • Reducing the amount of organic waste going to landfill and the related greenhouse gases.

What can I put in my Compost?

  • Vegetable and fruit scraps
  • Fallen leaves and fruit
  • Tea leaves and tea bags
  • Coffee grounds
  • Vacuum cleaner dust
  • Dead flowers
  • Soft stems of plants
  • Egg shells
  • Old newspapers (shredded)
  • Lawn clippings
  • Twigs and straw
  • Sawdust and small amounts of wood ash or lime
  • Tissues

What can't I put in my Compost?

  • Meat, fish and dairy products (they attract rats and vermin and can smell)
  • Large branches (they won’t break down)
  • Timber products treated with chemicals
  • Magazines
  • Diseased plants
  • Weeds with bulbs or underground storage parts (active compost will destroy most weed seeds)
  • Large amounts of bread or cake (they also attract vermin)
  • Plastics
  • Bones
  • Cat and dog droppings

Some of these items can go in your green organics kerbside bin and turned into mulch by commercial composter.

How to Compost

The composting process needs Air + Ingredients + Microorganisms + Time

1. Choosing the method

Your compost should be placed in a well-drained, shady position. There are many types of compost units that you can use to compost at home. Whichever bin you choose it is important to operate it aerobically, that means with the help of oxygen, to reduce the potential of unpleasant odours.

Types of units include:

  • Plastic bins with ventilation holes or slits in the side.
  • Metal drums with holes in the side and the base removed.
  • Metal or plastic rotating drums (tumblers) on a stand.
  • Enclosures made from timber, bricks or chicken wire.
  • Open heap (should be covered with a plastic sheet or Hessian material).

It is necessary to weigh up the advantages and disadvantages of each method as some designs may attract unwanted animals and vermin or may not be suitable for small properties.

Worm farms are a great alternative to backyard composting for people who live in units or courtyard blocks. Worm farming can turn your kitchen scraps, small garden waste and even dog poo into fertiliser, called castings. Worm castings can be applied to pot plants and garden beds as well as to potting mix as a soil conditioner.

Compost units and worm farms are available for purchase from most hardware stores and nurseries.

2. Collecting the Ingredients

Your compost needs a mixture of nitrogen-rich (green) materials such as fruit and vegetable peelings, fresh grass clippings, weeds and manure and nitrogen-poor (brown) materials such as dry leaves, woody twigs, paper, straw and wood ash. Add some completed compost or rich soil to your compost ingredient list as this will provide the micro-organisms that help break down the compost ingredients and turn them into rich, soil-like compost.

3. Layering

To build the compost, start with a thick layer of coarse material, such as twigs or mulch, follow with a thin layer of food scraps, then a layer of mature grass clippings, then a layer of manure and so on. Make sure you add water to the heap after each layer.

4. Maintaining your Compost

To assist the composting process you should:

  • Regularly mix and turn your compost material to allow air penetration.
  • Keep the compost moist, but not too wet.
  • Add greens and browns as required for that system but keep layers thin.
  • Place the compost unit in a well drained position, partially shaded from the sun.
  • Tear or break up your ingredients into small pieces before adding them to the unit.

How to Use Compost

It can take between six weeks and six months for the compost to be ready for use. It all depends on the mix of organic materials and how well the compost process is working. The compost is ready to use when all materials added are unrecognisable and it resembles a deep brown, rich and sweet smelling soil. Use your compost to feed your plants, spread over your lawn, act as a soil conditioner and be a starter for a new compost heap.

Health Precautions

Compost is produced from the breakdown of natural materials and can contain a variety of living organisms such as bacteria and fungi. On rare occasions these organisms have been associated with illness and allergies in humans. When dealing with compost it is important to take the following precautions:

  • Wash hands after handling compost or soil materials.
  • Protect broken skin by wearing gloves.
  • Keep the compost pile moist to prevent fungal spores or bacteria becoming airborne.
  • Avoid inhalation of dry compost.
  • If you suffer from illness or allergies wear a face mask.

Hints for Healthy Compost

Rats and Mice

Rats and mice are attracted to compost units by the warmth generated by the pile, when inappropriate materials such as meat, dairy, fish and cakes are added or when food scraps are left too close to the surface. To reduce the potential of attracting rats and mice to your pile do not add inappropriate materials and cover kitchen scraps with a layer of soil. If your compost unit has a lid make sure that it can close securely.


Most of the flies around a compost heap are small vinegar flies, which are harmless. If the flies being attracted to your compost are houseflies or blowflies then they are most likely being attracted by meat, dairy foods and manure. Again, avoid adding these materials and cover any other food scraps with a layer of soil, grass or leaves.


If your compost is generating unpleasant odours it may be because your pile is too wet or is not getting enough oxygen. To improve aeration, turn and mix your pile fortnightly. If your pile is too wet you will need to add more nitrogen poor materials to the mixture and improve drainage.


Ants can be attracted to compost units if the pile is too dry, not hot enough in the middle or has kitchen scraps too close to the surface. Make sure that your compost pile has the correct mix of greens and browns to ensure high temperatures during decomposition and add the required amount of water so that your pile is moist (like a damp “squeezed out” sponge) but not wet.

For further information please contact Council on 8372 8888 or at