Composting helps reduce waste and contributes to environmental sustainability. Since food and other compostable materials make up 20% of waste at the landfill, compost offers the best alternative for handling organic waste. It also helps in reducing the Greenhouse Gas produced when organic waste is dumped at landfills. Composting the waste also reduces pressure on city council or responsible organizations for acquiring land used for landfilling.

What is Compost?

Compost is a decomposed organic material that can be used to improve soil’s physical, chemical, and biological properties. Compost is rich in plant nutrients and beneficial organisms like bacteria, protozoa, nematodes and fungi which improves soil fertility in gardens, landscaping, horticulture, urban agriculture and organic farming thus reduces dependency on commercial chemical fertilizers. 

A compost is made by decomposing a mix of green waste (nitrogen-rich materials such as leaves, grass, and food scraps) and brown waste (woody materials rich in carbon such as stalks, paper, and wood chips). Generally, it takes approximately six to nine months before the compost is ready for use. The length of time taken for the compost to be ready depends on whether the compost has adequate amount of water and right size of wood chips, and how often the materials are turned for aeration.

 

Deciding on your composting method

Information about each option

• Enclosed Compost Bins
• Tumbling Composters
• Three-bin composting design
• Bokashi System 
• Worm Farming

Green and brown matter

Green (Nitrogen Rich, Wet)	Brown (Carbon rich, dry)
Fruit scraps	Dry leaves
Vegetable scraps	Straw
Coffee grounds	Hay (old and dry)
Tea Leaves	Pine needles
Spoiled produce	Cornstalks
Fresh grass clippings	Untreated sawdust
Fresh Leaves	Wood chips
Garden Trimmings	Tree Barks
Weeds without seeds	Shredded newspaper
Plant stems and green branches	Shredded cardboard
Fresh flowers	Paper towels
Seaweed	Paper bags
Brewery Waste	Toilet Paper rolls
	Egg cartoons
	Vacuum Cleaner dust
	Natural fiber fabrics (cotton, linen, wool)
	Nut shells
	Egg shells
	Twigs and sticks
	Wood Ash

 

What not to compost

Although in theory anything organic can be composted, some things are best avoided when composting at home.

Material	Reason
Cat and dog faeces	Can cause disease
Meat, fish, oil, bones, fat	Can attract rats
Non-organics e.g. tin, glass, plastics	Won’t break down
Invasive weeds, e.g. kikuyu, wandering willy, jasmine	Could spread in or beyond your garden – however they can be composted after treatment.
Large amounts of pine needles or gum leaves	Allopathic - create environment hostile to compost creatures
Woody materials in pieces larger than the diameter of your finger	Too slow to break down
Diseased plants (e.g. with blight)	Disease may spread
Bamboo, flax and cabbage tree leaves	Not suitable for composting and not taken by composting companies (bury in the ground, or take to a resource recovery center for landfilling)

 

To take note!

Plants like honeysuckle and Mexican daisy are considered pests therefore controlling them is essential. Species such as ginger, jasmine, and privet can cause serious damage to our native environment. Pre-composting practice is essential for composting invasive weeds. These can be done by:

• Put the weeds in a large plastic bag with a handful of soil and water.
• Tie the top and leave for at least two months, until there are no green shoots or other signs of life.
• Add them to your compost heap as green.

Common Composting problem

In general, all composting practices have problems faced when doing them. The table below is a summary of the common problems in all practices.

Problem	Cause	Solution
Smelly, slimy heap	Not enough air	Turn heap
	Too wet	Add brown material (e.g. dry leaves)
	Too much nitrogen	Add brown material
Materials are not decomposing	Heap too small	Increase size of heap
	Not enough heat due to lack of green materials or water	Add green materials
	Materials in heap are too large	Break materials down into small pieces
Pests attracted to heap e.g. flies, cockroaches, rats, mice	Wrong food added	Don’t use meat/bones/fish Bury food scraps in center of heap
	Bin not rodent proof	Rodent proof your bin
Fruit flies (vinegar flies)	Heap is too acidic	Sprinkle lime on heap
Ants	Heap is too dry	Add water and lime