Composting is nature's way of recycling. And turning food scraps into nutrition-rich organic soil in your garden can help create an eco-friendly backyard.

Composting is also an affordable way to reduce organic waste and divert it from landfills. It can be made from anything which was once alive, from food scraps, soil, garden litter, mulch, coffee grounds, flowers, vacuum cleaner dust, to hair and cardboard.

To minimise both greenhouse gases and unpleasant odours, composting needs to occur aerobically, that is, with plenty of air, so that carbon dioxide is produced instead of methane. This carbon dioxide does not contribute to the enhanced greenhouse effect because it is derived from biomass and is part of the natural carbon cycle.

If composting occurs anaerobically, that is, without enough air, methane is generated and foul odours are produced.

These odours are caused by the generation of ammonia, hydrogen sulfide and volatile organic compounds.

Methane generated from waste is over 25 times as strong a greenhouse gas as carbon dioxide.

The best way to ventilate your compost is by turning it regularly. This can be done with a shovel or garden fork, or even more easily with a compost corkscrew.

Some examples of compost corkscrews are
- Compost Mate, available from many hardware stores and garden centres
- Tumbleweed Aerator

Adapted from information supplied by horticulturalist Diana Gibson.