Last Updated Oct 11, 2016 · Written by Rob Schneider
Thousands of tonnes of kitchen and garden waste go to landfills every year. Much of that waste could have been used to create garden fertiliser. Compost bins or heaps are easy to maintain and create great fertiliser. Here's everything you need to know about creating your own compost.
When you create compost, you are creating an environment that allows bacteria and other micro-organisms to break down food scraps, leaves and other organic material. When the material is broken down, the compost contains nutrients such as phosphorous, nitrogen and potassium. It's not hard to make compost, but any compost heap requires certain key elements:
As bacteria, algae, fungi and other micro-organisms feed on the material, it becomes hot. The heat is important because it helps speed up the composting process; prevents flies and cockroaches from breeding; and kills diseases.
If you provide the right balance, compost heaps will not smell or attract flies or vermin. With just a little effort, you can produce enough compost to fertilise your garden. Compost makes some of the best fertiliser available. Better yet, after you've bought or built your compost bin or heap, you will have free fertiliser whenever you need it.
Compost heaps require the right mix of carbon materials and organic matter. These are often referred to as "browns" and "greens."
It's also important to know what not to put in your compost heap. "Woody" garden clippings include branches, roots, thorny branches (such as roses), nettles, conifer prunings and pine needles. These will not break down. An exception is roots, but if you put roots in your compost heap, you need to chip them first. Other things you should not put into a compost heap include:
Any material must be able to break down and not harm the compost heap. Some materials that kill bacteria include fat, oil and anything that contains chemicals (such as insecticides, herbicides, pesticides, disinfectants and antibiotics), so don't add these materials to your compost heap.
If you have a small garden, a compost bin may be all you need. You can buy compost bins from garden suppliers and nurseries. Some types of commercially available compost bins include plastic bins and tumbling bins. Plastic bins should be made from UV resistant plastic and some are made from black plastic to help keep the compost hot.
It's also easy to build your own compost bin or heap. Traditional compost heaps are made from untreated timber. They should be at least one cubic metre in size to allow the material to heat up to the right temperature. If you don't need such a large bin, you can use a garbage bin. Cut out the bottom and use the lid to keep rain and vermin out of your bin.
Find a shady spot for your compost bin. To keep vermin out, either place wire mesh under your bin or bury the bin to a depth of at least 100mm or more. Put some sticks in the bottom of the bin to help drainage and improve air circulation. Then add a layer of green material followed by a layer of brown material. Two parts brown to one part green is ideal.
If you want the ultimate fertiliser for your garden, create compost and also start a worm farm. Read Build Your Own Worm Farm to learn how. Like compost heaps, once established, worm farms are easy to maintain and worms in your garden will aerate your soil and their "castings" make great fertiliser.
It may take a little practice to get your compost heap just right. These are some common mistakes and their solutions:
In time, you'll know exactly what's right for your compost heap and maintenance will be easy. Just remember to aerate the bin or heap weekly by turning the pile. It can take between one and two months to create your first garden fertiliser. If you don't turn it regularly, it will take six months to a year, so be sure to turn it regularly. You'll know your heap is ready to spread on your garden when it has a crumbly appearance throughout. To have a steady supply of compost, build or buy a second bin and you can have nutrient-rich compost on hand whenever you need it.