Last Updated Nov 17, 2010 · Written by Craig Gibson
Composting is an easy and worthwhile way to limit both your household waste and greenhouse gas emissions. Generally, a compost bin or heap sits in a sunny corner of your garden. However, if you live in an apartment or if you have very limited outdoor space, such as a townhouse, it is still possible to compost.
Composting is a way of turning organic waste such as food scraps into useful fertiliser for your garden. Something like half of all domestic waste can be composted. This includes fruit and vegetable peeling, leftover food scraps, grass and garden cuttings, newspapers and even dust and hair. You can compost in a ready-made compost bin, available from most hardware or garden stores, or you can make your own compost heap simply by piling up food scraps and garden cuttings in a warm spot in the garden and covering them with a black plastic sheet.
There is a key difference between the way organic matter breaks down in compost and in landfill. Organic waste in landfill contributes to global warming by producing methane, a greenhouse gas many times worse than carbon dioxide. Because it is buried, there is no oxygen so the microbes and bacteria that would normally break organic matter down harmlessly cannot survive. On the other hand, when you compost, the air in your compost pile allows these organisms to thrive and process the waste naturally, turning it into nutrient-rich fertiliser. Not only does this avoid the production of methane, but healthy soil actually absorbs and stores carbon dioxide.
Worm farms are relatively compact and will fit into many nooks and corners. You can buy them at garden and hardware stores. The worms digest the food scraps and excrete a nutrient-rich liquid that drains out of the bottom of the worm farm and can be used as a plant fertiliser.
If you’re very tight on space you can make your own smaller worm farm by stacking plastic containers, such as ice cream cartons. Place the food scraps in the top container, then the earth containing the worms in the middle container, with a lower container to collect the liquid runoff. Make some holes in the bottom of the upper two containers so that the liquid from the decomposing food and then from the worms drains through to the bottom.
You can also make a miniature compost bin using something like plant pots. Make a hole in the bottom so you can remove the finished compost. Cover the top of the pot with some black plastic and leave it in a sunny spot. If the pot is not standing directly in soil, place a drip tray underneath it to collect liquid runoff. Empty this tray regularly so it doesn’t become a breeding ground for mosquitoes.
A Bokashi bin is a commercially available system invented in Japan. The system consists of an airtight plastic bin that is small enough to fit under most sinks. You put food scraps into it and sprinkle a small amount of Bokashi mix. This contains micro-organisms that break down the waste. Because the Bokashi bin is airtight, there is no odour and it does not attract insects or rodents, so it is a good way to compost meat and fish as well as other food and organic waste. The bin has a tap to drain off the liquid, which is a rich fertiliser. When the bin is full and the liquid has been drained, you can bury the dried solid matter in soil, where it will break down quickly into compost.
Finally, you can even put your food scraps into a blender, add some water and whizz it into a thick juice. Take this juice outside, lift up a layer of soil and pour the juice into the ground, replacing the soil afterwards. Cover the area with some mulch so it doesn’t attract flies.
Even if you don’t have a garden, you can still find useful ways to use the compost. For instance, you can use it on potted plants and window boxes, or give it to a local community garden or school garden. Or you could just put it on a grass verge or any other green space!