This page covers the basics of backyard compost bins, bokashi bins and worm farms.
Backyard compost bins, bokashi bins and worms farms are popular options for dealing with domestic organic waste. You can buy what you need from hardware stores, or make your own.
You can also download this information as PDFS.
Each compost method requires a different composition of 'greens' and 'browns'. The graphic shows what's green and what's brown:
|Compost bins||Bokashi bins||Worm farms|
Compost bins should be located in a sheltered level area of the garden with good drainage and access. The site should be in a warm sport but not in full sun.
What to add
Avoid meat, fish, oils, dairy products, bones, glass, plastic and garden weeds.
Get the best from your bin
Add your waste layer by layer. Kitchen and garden material will compost much quicker when chipped, chopped or crushed into smaller pieces. Soak paper and cardboard in water prior to composting.
Keep the pile moist like a sponge, but not soggy wet as this will stop the air circulating.
Cover your compost with a lid. This keeps the heat in and traps moisture. Newspaper and cardboard can help if it gets too wet.
You should try to turn your compost regularly to increase air circulation, ensuring that there is an adequate supply of oxygen to aid the break down process.
Harvesting your compost
Simply lift the bin up and off. The mature compost is ready to use.
Material at the top will be only partly composted. Simply put this back into the empty bin.
Bokashi bins use a fermentation process - the word 'bokashi' is Japanese for 'shading off' or 'gradation'.
Bokashi requires a fermentation powder called ‘Zing’. Zing ferments the compost like a pickle. It contains sawdust, molasses and effective micro-organisms. You can purchase Zing from the bin supplier.
What to add
You even add these to your bokashi bin: Meat bones, shellfish, cooked food, citrus, tea bags and coffee grounds.
But avoid these: Liquid or soft dairy products (like milk and yoghurt), oils, large meat bones, soups and other liquids.
Get the best from your bokashi bin
Sprinkle zing in the base of your bin. Transfer food scraps into your bin. Squash (this keeps the air out), then sprinkle zing over the food scraps as per the instructions on your Zing. Keep the lid sealed.
Keep layering food scraps, squashing and adding a sprinkle of Zing until the bin is full. Drain the liquid from the bottom bucket as required.
When the bin is full, seal and leave in a sheltered place (start using the other set for your food scraps). After 10-14 days, your bokashi is ready to be added to your compost or buried in the ground.
Using the liquid and food scraps from your bokashi bin
The liquid from the food scraps drains into the bottom bucket. Drain this regularly.
Use on your garden as a liquid fertiliser.
After the full bokashi bin has fermented for 10-14 days the scraps can be buried in your garden, or add as a ‘green’ layer to your compost bin.
If they're buried in the garden, you can plant over them in three or four weeks.
You can buy worms online, or ask a friend to share.
Find a sheltered place, not in direct sun for the worm farm. A carport is ideal. If your worm farm does not have legs, use bricks or pavers to lift it to make space for a container under the tap.
What to add
Avoid onions and garlic, citrus, meat and bones, cooked food.
Getting the best from your worm farm
To set up the first layer, add newspaper bedding, worms and a small amount of food. Cover with damp carpet, sacking or newspaper, then the lid.
Then keep adding browns and greens until each layer is full. Add food scraps regularly. Keep pieces of food small for your worms – about the size of a golf ball is best.
Using liquid and castings from worm farms
Liquid from the worm farm drains into the bottom bucket. Empty this regularly. Dilute one part of ‘worm tea’ to 10 parts water. Use on your garden as a liquid fertiliser fertiliser around the base of your plants.
Empty the bottom layer of your worm farm first, when the contents look like a dark fine compost. Spread this around your garden bed. You can also add one part castings to 10 parts water and use as a liquid fertiliser around the base of your plants.