When organic material is composted, it decomposes or decays and turns into organic fertiliser ideal for plants.

Composting is a great way to reduce the effects of kitchen and garden waste on the environment by reducing greenhouse gas emissions even without anaerobic digesters. When recycling organic material like garden waste and food and yard waste, put it into a compost bin and keep it moist. Compost piles will not break down properly without water or lots of wet materials.

What kind of organic material is used to make compost?

All kinds of organic material can make good compostable materials to add to your compost bin. These include yard waste like leaves, grass clippings, dead plants, flowers, food scraps, and animal manure. If the only thing you have a lot of is grass clippings or leaves, that's fine! Composting is a good waste management too. Add some food from time to time as well to keep it interesting.

What do you need to make compost?

You may already have the organic waste that you need around your home. There are two main composting materials; green materials and brown materials. Green materials include fruit and vegetable scraps, fresh grass clippings and other fresh plant material. Brown materials include things like straws and paper, and wood chipping. One or two bins that are open at the top (some people like using old plastic garbage cans), some bags of dirt, and a shovel if needed are all you need. If interested, several types of composting machines are available for purchase at home improvement stores. You can also have a pile of compost within your backyard if need be.

How long does it take for compost to break down?

It takes about two weeks to make compost in your bin, although larger bins will take longer than smaller ones. Some people may want to leave the bin open for 3 or 4 months before emptying it into their garden, but that is up to you! Also, you can turn the organic materials regularly to speed up the composting process.

Do I have to keep the pile wet while making compost?

Yes. To create good compost, you must keep your pile moist at all times until it's ready for use in the garden. Excess water should drain easily from the pile when turned occasionally, causing no harm to plants below in containers or raised beds.

Can I make compost with wood scraps?

Yes, you can make compost by using an organic material such as wood or even sugar cane. You'll want to break down pieces into smaller chips and then add them into the pile. If you're adding a lot of this type of material, try not to add more than 1/3 of it to your pile at a time. Some people like making worm balls out of excess worms from their bin; they use these balls in place of some other organic waste and food scraps in a pile.

What are worm castings?

Worm castings are also known as vermicastings and earthworm gold. They are an entirely natural fertiliser made from a biological process where earthworms feed on garden waste and kitchen scraps while assisting in the proper aeration of the soil and extracting water and other nutrients. Worm castings contain six times more nitrogen than cow, sheep or other animal manures, five times the phosphorus of superphosphate and nine times the potassium of muriatic of potash, all required for soil amendment to produce magnificent vegetables and fruit through a natural process. Worm castings are a great addition to garden in black mulch.

Can I use coffee grounds in my compost?

Coffee grounds should be used sparingly in your compost pile due to their acidic nature, killing some bacteria you need for everything to work well together. If you like adding coffee grounds (and discourage it), add them during the first couple of weeks while the organic material is still wet enough that it will not burn seeds while decomposing. You can collect your kitchen scraps that would otherwise be thrown out while cooking meals and add them to your bin instead.

Can I add worms to my compost?

Although not necessary, you can add different kinds of worm castings into the pile. Add them before winter or any other time when they leave your garden in search of food. You will know that they are dying off when it starts becoming cold, and there are no more earthworms to be seen around your bin.

How do I make my own compost?

Here is a composting method to get your compost pile started and save you money used to buy peat moss;

For home composting, find an area where you want to create your compost pile: you could use a box or container. You'll need about 1sqm of space. If possible, choose an area that gets direct sunlight all day long; this speeds up the composting process significantly. Generally speaking; however, any shady spot will do just fine. Keep in mind that the compost pile will need to be turned now and again, so it's best to do this easily.

Make sure your compost pile is far enough away from any other plants in your garden. You don't want human, dog or cat waste getting into your soil (if using animal dung, bear in mind that it may attract predators who could cause damage). If possible, choose an area near a water source since worms need to stay moist at all times.

Layer leaves with grass clippings. When turning the pile later, turn this layer first to decompose quickly. Add 10-15cm of leaves followed by 15-20cm of grass clippings/straw. You can also use other organic materials to start with, but these are the easiest to compost.

Cover this mixture with 10cm of soil before adding your kitchen waste. The layer should be no more than 20-25 cm thick - you'll know when it's time to turn the pile when you have reached this limit, as the first 4 layers will have started liquefying and decaying by this point.

Add any food scraps you have, plus an eggshell for every two cups of greens/vegetable scraps that you have added into the bin, along with some water to keep everything moist. It will help activate the microbes that are needed for decomposition. Don't add oils or fats, although tea bags are fine. The moisture will help prevent the bad odours associated with composting, so don't worry about it becoming too wet. If you suspect any meat has gotten into your compost pile (either by accident or on purpose), add some worms or other vermicomposting worms to improve decomposition and reduce the smell.

Keep your compost pile moist as this will help it get ready for turning faster. If necessary, use a hose, especially in dry weather when water naturally becomes scarce. You should turn your compost regularly until it is done. This usually takes 1-3 months, depending on size, temperature and how often you turn it over. When finished, your compost can then be used as fertiliser in the soil for plants.

How do I turn my compost?

You'll want to turn your pile regularly. For this, you will need a pitchfork or shovel. If the pile is too large or dense to turn entirely, try breaking it up into small sections before turning each one over. When turning over the compost pile, be sure to mix everything well - there shouldn't be any dry spots in between moist ones. Doing this ensures that all materials receive proper amounts of oxygen and moisture during decomposition. The finished product should look like crumbly rich soil. You can use finished compost on plants, vegetable gardens or flowerbeds right away. The added nutrients will help your plants grow strong.

What is the difference between soil and compost?

Soil is a mixture of minerals, organic matter and water that forms a ground cover. On the other hand, compost is an organic product made from recycled organic matter such as decaying leaves and animal waste; it's rich in nutrients, which make it perfect for growing plants. As compost continues to break down, it will become soil in due time.

When is compost finished?

You'll know your compost pile has decomposed into nutrient rich fertiliser when the following things happen, outlined below.

  • It has a uniformly dark, rich colour and texture (it will be crumbly and moist).

  • There is no odour. If your compost smells bad, it means you haven't added enough grass clippings to balance out the greens.

  • You can see tiny worm casings on top of the pile, indicating that worms and microbes are present and decomposing trash.

  • Your compost should have doubled in size since you started because the pile has trapped an incredible amount of moisture inside it that allows for aeration. Remember to turn your finished compost back into its smaller form before using it again.

How is finished compost used?

Adding compost helps to enrich soil. You can add it to garden beds or flowerbeds just make sure you produce finished compost. You can use either cold composting or hot composting for backyard composting. Cold composting takes at least 6 months before it is ready. The decomposition process is sped up for hot composting and compost can be ready in one to three months. Finished compost contains all the nutrients plants need for healthy growth, including nitrogen, phosphorous and potassium obtained from organic matter. However, immature compost is unsafe to use. You could also make and use compost tea from your finished compost. Compost tea from finished compost. When used as fertiliser, finished compost also enriches the quality of your garden's soil.

For more information, the South Australian Department of Environment has a handy guide to composting.