What is composting? Composting is the process of recycling organic materials into a rich soil known as compost. Kitchen (food scraps) and garden (leaves and grass trimmings) waste is biodegraded and turned into an organic fertilizer which can be used on garden beds. The composting process is carried out under controlled aerobic conditions where the organic matter is broken down by microorganisms, including bacteria and fungi, into simpler substances. These substances are consumed by invertebrates with the resulting nutrients returned to the soil to support plant growth. An effective composting process is dependent upon oxygen, temperature, moisture, organic matter and size; these components have an impact on the activity of microbial populations and the end result of your compost. Benefits of a compost bin A compost bin can break down large amounts of food scraps faster than a worm farm, however you will need an outdoor space and garden cuttings to mix in with your food scraps. While composting has many environmental benefits including reducing the amount of recyclable waste sent to landfill, it s best to avoid food waste in the first place. Try planning your weekly meals in advance and only buying ingredients you need for those meals. Not only will this reduce the amount of food waste you produce, but you will save money as well! Composting methods There are two main methods of composting: Cold composting This is the most convenient way to compost your food scraps regularly. The compost will generate heat but because scraps are added gradually it won t get really hot. This method can take approximately three to six months for the compost to be ready. Hot composting This is when you fill the compost bin in layers all at once and leave it to cook stirring and adding water occasionally. This method will create compost in approximately six to ten weeks.
What you need to get started Compost bin Container to collect food scraps in Food scraps Garden scraps Water Compost aerator; you could buy a compost mate tool but a garden fork/shovel will work just as well How to start your compost 1. Choose an outdoor location where your compost bin will be on bare earth with good drainage. Find a convenient spot that you can easily access. Placing your compost on soil, sand or gravel will provide good drainage, reducing the chances of your compost becoming too wet or smelly. 2. Once your bin is in place, add a decent layer of mulched dry garden leaves or good clean soil, to the base. Alternatively use existing compost to line the base. 3. Add your food scraps and some water to the compost bin, and mix through. Chop food scraps into pieces smaller than a golf ball. The smaller the pieces the faster they will break down.
4. Your compost should have a balance of food scraps and garden waste. Each time you add food scraps to your compost bin, remember to add garden waste also. Have a pile of mulched up garden scraps near your compost bin that you can easily add in, each time you add your food scraps. 5. Each time organic material is added to the compost bin, you should add some water to maintain moisture. Remember to stir the contents to introduce oxygen throughout the bin.
What can go in a compost bin? Kitchen scraps Vegetable and fruit scraps (including citrus) Coffee grounds and filters Tea bags and tea leaves Egg shells Nut shells (except for walnut shells) Food scraps are wet and high in nitrogen which helps compost break down Garden scraps Dry leaves Straw and dry hay Woodchips and sawdust from untreated wood Dried grass clippings Fresh grass clippings Plant trimmings from your garden Houseplants Garden scraps are dry and high in carbon so they ll stop your compost from smelling Other organic materials Shredded paper Hair and animal fur Paper towels, and paper tubes Dryer / vacuum cleaner lint Cotton balls (providing they are 100% cotton) Cotton swabs made from 100% cotton and cardboard (not plastic) sticks
What can t go in a compost bin? While anything organic can be composted, unless you are experienced we recommend avoiding the following: Bread products: This includes cakes, pasta and most baked goods. Small amounts are ok, but large amounts can attract unwanted pests. Cooking oil: This can upset the compost's moisture balance. Diseased plants: Fungal or bacterial problems from diseased plants could transfer to whatever ends up growing in your finished compost. Heavily coated or printed paper: Magazines, catalogues, printed cards and most printed or metallic wrapping paper. Foils don't break down, and you don't want exotic printing chemicals in your compost. Human or carnivore faeces: This includes kitty litter. Waste and bedding from noncarnivorous pets are fine. Meat products: This includes bones, blood, fish and animal fats. These are likely to attract pests. Milk products: Refrain from composting milk, cheese, yogurt and cream. While they'll certainly degrade, they are attractive to pests. Rice: Cooked rice is fertile breeding ground for the kinds of bacteria you don't want in your pile. Raw rice will attract varmints. Sawdust: Unless you know the wood it came from was untreated, stay away. Stubborn garden plants: Dandelions, ivy and kudzu are examples of plants or weeds which would regard your compost heap as a great place to grow, rather than decompose. Walnuts: These contain juglone, a natural aromatic compound toxic to some plants. Seeds of weedy plants: These are more likely to grow inside your compost bin than break down. Anything treated with pesticides: Chemicals might kill beneficial composting organisms.
Harvest time Your compost is ready to harvest if it looks like dark, rich soil and smells earthy. If you are using the cold composting method, this will normally take three to six months. You can spread the compost around plants or mix it with soil to create your own potting mix. Always cover soil and compost with a layer of mulch to keep it alive and thriving. Tips Compost is always good for vegetables and exotic plants, but is often too rich for native plants. A common harvesting problem is finding small patches of ready compost mixed with recently-added food scraps. This can be avoided by only stirring the top half of your compost, allowing the ready compost to accumulate at the bottom. Don t worry about eggshells or avocado seeds not breaking down. If the rest of the compost is black, fluffy and smells earthy then it s okay. The eggshells won t be visible in your garden once you add a layer of mulch over the top. If it s not quite ready to harvest but you want to start another compost (and don t have another bin) - lift the bin off the compost pile, cover it with a tarp or rug and leave it for a few weeks until it s ready.
Troubleshooting My compost doesn t seem to heating up. If you are following the cold composting method (adding organic material regularly), then chances are your compost won t reach high temperatures. If you want to try introducing heat into your compost, you may need to increase the volume of your compost and add more nitrogen (food scraps or fresh grass clippings). Should my compost smell? If your compost starts to smell, you may not have introduced enough oxygen into the mix (a result of not stirring) and could be too wet. Give the whole compost a good stir for aeration and add more garden scraps. If the smells are strong, you can sprinkle ash, dolomite or garden lime on top. It s taking a long time for my waste to break down. It is probably too dry or cold. If the compost is dry, soak it with a hose. Adding more food scraps or moving your compost to a warmer spot will speed things up. There are cockroaches in my bin; is this ok? Cockroaches like to hide in warm, dry, still patches. If you see cockroaches in your bin, this means your compost isn t moist enough and hasn t been stirred for a while. Add some water to your bin and mix the components around. There are signs of mice and rats around my bin. They could be attracted to your compost if it smells. Avoid adding grains, meat, eggs and dairy. Check the lid is secure and there are no gaps. Rat-proof your bin by lining the base with chicken wire. Need more help? If you have any questions regarding your composting, get in touch! Facebook: Twitter: Email: facebook.com/zoosvictoria twitter.com/zoosvictoria zoosvic@zoo.org.au