The benefits of composting at home
Food and garden waste are not suitable for landfill. There is a common misconception that biodegradable material is fine in a landfill and will break down safely long before everything else. However, the opposite is often the case. Food waste in landfills often does not break down because it is compacted and not exposed to oxygen. This prevents normal decomposition. Organic matter in landfills rots anaerobically (without oxygen) in a way that produces the greenhouse gas methane.
There is another problem, when this rotting matter leaks liquid out of the landfill, carrying toxins from other rubbish with it and polluting the soil and waterways. When food waste is composted at home or at commercial composting plants, there is no risk of methane, because oxygen is present.
Although NZ does not have the same urgent landfill problems as more populous countries, even here we are reaching a point where landfill space is becoming limited and expensive. Containing and treating the rubbish safely is also very expensive.
About 50% of household rubbish in New Zealand is compostable material, including garden waste and food waste. So stopping this organic matter going into landfill would make a huge difference.
The other benefit of composting is that you can also put in garden waste such as weeds, hedge and grass clippings (instead of having to pay to dispose of them). In fact your compost will love it. Then you can use the resulting rich soil to fertilise your garden.
Compost bin (this is the easiest)
The general rule is that you should layer different types of waste in your compost bin – if it’s all fresh food waste and green garden waste, it won’t get the right amount of air circulation. The best situation is where you alternate layers of dry leaves/grass clippings (you can also add untreated wood chips, shredded paper and cardboard to this layer) and thin layers of green or food waste. The dry layers should be about twice a thick as the fresh/green layers. Chopping up your waste (especially woody hedge clippings) into smaller pieces also speeds up the process, but is not necessary. It helps to have some airflow at the base of your compost bin, so you can start off your compost by arranging some twigs at the bottom
A worm farm is a basically compost bin with worms introduced to help speed up the process. Fresh fruit and vegetable scraps and peelings (not citrus) should make up the majority of your worm food. You can also add paper and cardboard to you worm farm, but make sure it doesn’t make up more than 30% of the contents. There a few things worms don’t like, especially spicy or acidic foods, cooked or processed foods, meat and dairy. But they can handle coffee grinds, tea bags and egg shells.
Worm farms come in many shapes and sizes. You can use an old bath tub, a barrel, small crate or homemade frame. The bottom should be lined with coconut husks, shredded cardboard or hay to provide airflow. You’ll need to put the worms in yourself. Don’t add too much worm food for the amount of worms – increase this as the worms multiply.
Hot compost pile
This is suited to people who have a lot of garden waste and need large amounts of compost quickly. This produces very good compost and quite quickly, but requires a bit more effort and a large amount of the right types of organic garden waste. A hot compost pile is a large heap of alternating layers of green and brown waste material, which heats up quickly as it starts to decompose. If it cools, it can be turned with a shovel to mix more air in and increase this activity again.
More detailed information on various methods of composting (including workshops) can be found at The Compost Collective.