Why compost?

Every year Kiwis throw away more than three million tonnes of rubbish, of which more than 45% is food waste!

Every 6kg of unsorted rubbish sent to landfill emits nearly 5kg of carbon dioxide – a greenhouse gas - into the atmosphere. Yet most of what we throw away could be sorted and disposed of in a far more eco-friendly way.

What is compost?

Nature’s recycling system

Your household produces an enormous amount of waste each year that could be composted. Having a compost or worm bin in your backyard is a great way to reduce your waste and help protect the environment.

Home composting has many benefits

• Compost is a natural fertiliser and soil conditioner. It improves soil fertility and texture, and retains moisture and nutrients.
• It is cheap and is easy to make.
• The amount of water pollution, gas release and odour from landfills is decreased.
• Air pollution is reduced from burning garden waste.
• Your garden will require fewer garden chemicals because compost-rich soil grows healthier, more productive plants which often have more resistance to pests.
• Compost or mulch also reduces the amount of water used because soil does not dry out as fast.
• Composting is easy and you can choose a system to suit your lifestyle. You may compost at home with a compost bin or worm farm, get a garden bag company to collect your garden waste or deliver your garden waste to a composting drop-off point at your local refuse transfer station.

Compost

Getting started

You can either buy a compost bin or make a wooden box for the compost. If you are building one, remember to leave space between the slats of wood for air circulation.  A 1 x 1 metre compost bin is a good size.

All compost bins should be bottomless and placed on the bare ground in a sunny spot.

They work best in a warm, moist location. Begin with a bottom layer of coarse plant material like twigs, followed by alternate layers of garden waste and food scraps with a thin layer of soil.

What to include in your bin

You will need a variety of materials which are found naturally in your garden or come from the kitchen. They are called “Greens” and “Browns.”

Greens - are nitrogen-rich wastes like kitchen food scraps, fruit peels, coffee grounds and tea bags, grass and plant clippings, hair, animal fur, blood and bone, seaweed, fish bones and chopped weeds (except for Onion Weed, Wandering Jew, Wild Ginger and Oxalis).

Browns - are high in carbon and other elements. These may be dried leaves, sawdust, wood shavings, hay, peat, vacuum cleaner dust, shredded paper, and newspaper, eggshells and crushed seashells, coal ash, wood ash (untreated), chicken manure, blood and bone.

What to leave out of your bin

• Meat.
• Grease and fat.
• Dairy products.
• Large bones.
• Food packaging.
• Plastics and wood products.
• Pest plants - see our 'Weed and Pest Control' section for more information
• Underground stems, for example kikuyu grass stems.
• Cat and dog faeces are not recommended in large amounts. They may create an odour problem and there are very little nutrients in them.

Speeding up the process

• The smaller the pieces of food and garden waste, the faster it will decompose. 
• If you don’t have a lid on your system, cover the compost in heavy rain.
• Keep composting material moist – don’t let it dry out.
• If at first it doesn’t heat up, add more ‘green’ material, and manure or blood and bone.
• Composting slows down in winter, but you can continue to add organic materials.
• It’s fine if your heap freezes, but if you want your heap to continue decomposing throughout the winter, add an insulating layer of plastic over the heap.

When is it ready?

Ideally the finished product should look like potting mix. However, it will not matter if it isn’t perfect. As long as most of the material is broken down (egg shells will not completely disappear) and you have material with a soil like structure, your compost is ready to add to your garden.

Caring for your compost

Your compost bin or heap is not a dump!  The main ingredients for good compost are a good mix of materials, including greens like lawn clippings, to produce heat, moisture and air.

• Chop or shred garden waste up into smaller pieces and mix with other ingredients in the bin.
• Turn your heap or the contents of the bin. After it heats up and cools down, turn to mix the ingredients. The heat destroys the weeds and seeds. You may turn it into another un-layered heap or bin if you have one or just stir up the contents of your existing bin.
• Keep moist, but don’t drown your compost.
• Cover your heap or bin in heavy rain.
• If it becomes too wet, turn it and add ‘brown material’.
• Turn your heap if it develops a bad odour.