Green Waste and Composting

Composting at home

Composting is an easy way you can reduce the amount of waste going to our landfill. It is a natural process of decomposition that turns garden and kitchen waste such as leaves, paper, napkins and food waste into a fertile, organic soil-like material. Composting is sometimes referred to as organic recycling.

Compost is quite different from the material that it was made from. It is free from unpleasant odours, is easy to handle and stores for long periods of time. It is a natural plant food, soil conditioner and mulch, adds organic matter to the soil and encourages soil life and earthworms.

How to compost

There are many different compost systems to suit everyone. Whichever way you choose to compost, make sure you have a firm fitting lid to keep out unwanted rodents.

Choose a sunny area of soil to place your compost bin. Do not place your bin on concrete as you want worms to penetrate the compost to aerate the material.

You will need a variety of materials which occur 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 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 and blood and bone.

Alternate layers of garden waste, food scraps and organic waste with a thin layer of soil. Keep it moist and stir up the compost every one to three weeks with a shovel.

The smaller the pieces of food and waste the faster it will decompose.

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.

What shouldn't I compost?

Don't compost large quantities of materials that may cause unpleasant side effects such as attracting vermin or flies, or that may cause odour. These include meat, fish, fats or cooking/salad oils.

Also avoid wood pieces, bones, inert materials (such as tins, glass or plastic), diseased plant material, plant foliage with residue of chemical sprays (especially hormone type weed killers) and weeds such as Oxalis, live twitch, convolvulus, docks and dandelions.

Methods and bins

Compost heaps
These should be about 1 metre square and ½ to 1m high and covered with either old carpet or black polythene to keep in the heat.

Compost bins
Manufactured compost bins are neat, efficient covered containers that fit into a small space. There are a number of different bins available on the market or you can make your own.

Three bin method
This is good for large gardens and usually consists of a large wood slat bin divided into three compartments. The compost is turned from one bin to the next every four to six weeks and should be ready for use by the end of that period. The process of turning keeps the product aerated and well mixed.

Rotating drum
Achieves the turning process and makes excellent compost. Once the process has begun it is preferable not to add any more to the mix but wait the fourteen days for maturation and then begin again. This method is not usually used for food waste.

Trenching
A method often used in large gardens or farms and basically means that you bury the garden or food waste. Dig a trench and fill it in sections, covering with a good amount soil after each addition. Plant out on top.

Other composting systems

Worm farm – for uncooked fruit and vegetable food scraps.
Bokashi fermentation bucket – for food scraps, including meat and cooked leftovers.

See the Love Food Hate Waste website for ideas on how to use leftovers and 'scraps'.

Taking green waste to the Transfer Station

Green waste is processed into compost at the New Plymouth, Waitara or Inglewood Transfer Stations by shredding.

As the shredder uses rollers and cams to tear the plants apart, as opposed to cutters, stringy plants and oversize branches (greater than 150mm diameter) cannot be accepted at the reduced green waste disposal rate. Examples of these plants include ponga trees, agapanthus, flax, bamboo, ginger plant, gorse cuttings, cabbage trees and Norfolk pines.

Green waste containing contaminates such as stones, concrete, plastic, weed killers, etc is also not accepted.

To assist in processing green waste, please sort your waste into three types. 

  • Firewood (branches more than 75mm diameter). 
  • Material that can be shredded (prunings). 
  • Fine material (grass clippings).

Sometimes it is impractical to identify each plant separately and therefore load discretion and the disposal price is placed with the kiosk operator.