A worm farm turns fruit and vegetable scraps into rich food for your garden. It takes up little space and suits small yards, balconies and even laundries. Worms do most of the work for you. All they ask is shade, moisture and a steady supply of food.
Brisbane City Council says one worm farm can handle the food waste of a household of two or three people. That makes it a practical way to keep scraps out of the general bin. You also get two useful products in return. This guide walks through set up, feeding and fixing common problems.
Choosing the right worms
Ordinary garden earthworms are not the right choice for a worm farm. Frankston City Council says common garden worms generally cannot handle the conditions. Compost worms such as tiger worms, red wrigglers and Indian blues are the ones to use. You can buy them online or from large hardware stores.
Councils differ a little on how many worms to start with. Frankston suggests at least 1,000 worms, which weighs about 250 grams. Brisbane suggests starting with about 2,000. A larger starting group will get through scraps faster in the early weeks.
Finding the right spot
Location matters more than the type of box you buy. Brisbane City Council recommends a cool, shady area with no direct sunlight. A garage, laundry or shaded corner of the yard all work. Frankston also suggests a spot with good airflow.
Temperature is the main thing to watch. Redland City Council says worms will tolerate roughly 10 to 30 degrees Celsius. Frankston says they prefer 18 to 24 degrees. In hot weather move the farm into deeper shade, and in cold weather cover it with old carpet, blankets or hessian.
Setting up the bedding
Worms need a moist, dark bed to live in before any food goes in. Brisbane suggests lining the tray with a few sheets of damp newspaper or cardboard first. Add bedding such as shredded paper, cardboard or coconut fibre that has been soaked until it looks like sawdust. Redland suggests a bedding layer about 15 to 25 centimetres deep.
Spread the worms on top and let them burrow down by themselves. Cover them with damp sacking, cardboard or newspaper to keep out light. Redland says the bedding should feel like a lightly squeezed sponge. Never use garden soil or dirt as bedding.
Frankston suggests leaving the worms unfed for about a week. This gives them time to settle into their new home. Check the moisture during that week and add a little water if the top dries out. Then you can start feeding.
What to feed your worms
Most fruit and vegetable scraps make good worm food. Redland lists watermelon, apple, avocado, pear, carrot, cabbage and pumpkin as favourites. Worms will also eat soaked cardboard, newspaper, tea bags, coffee grounds and eggshells. Cutting scraps into small pieces helps because worms have no teeth.
Some foods cause trouble and are best kept out. They can make the farm too acidic or attract pests. Councils advise against the following:
- Meat, bones, dairy and fatty food
- Citrus fruit such as oranges, lemons and grapefruit
- Onions, garlic, shallots and chilli
- Raw potato, though cooked potato is fine
- Cake, biscuits and other highly processed food
Feed little and often rather than in big loads. Frankston says worms can eat about half their body weight each day. Brisbane suggests feeding every one or two days and covering the food with shredded paper, cardboard or dry leaves. Leftover food rots, so only add more once most of the last batch has gone.
Setting up a small scrap caddy near the sink makes this easier. If you are planning a lower waste kitchen renovation, build space for one into the bench layout. Be careful with packaging labelled compostable. Read up on greenwashing and credible sustainability claims, and keep plastics out of the farm unless you are sure.
Using castings and worm liquid
Worm castings are the dark material worms leave behind. Frankston says they take six to twelve weeks to build up. Brisbane notes that after a couple of months most worms move up into the top tray. You can then remove the castings from the lower tray.
Castings can be mixed with garden soil as potting mix or spread as a top dressing on lawns. Brisbane City Council suggests both uses. A garden full of native plants in sustainable landscaping can benefit from a light layer around new plantings. Little else in the garden costs so little to make.
The liquid that drains into the bottom tray is often called worm tea. Frankston and Redland both suggest diluting it about one part to ten parts water before use. Drain the tray regularly so it does not overflow. Leaving the tap open with a container underneath is an easy habit.
Fixing common problems
A healthy worm farm should smell earthy. A bad smell usually means too much food or too much moisture. Stop feeding for a while, add a little garden lime and gently stir the top layer. Brisbane suggests starting a second farm if you produce more scraps than one farm can handle.
Small flies tend to appear when the farm is too wet, too acidic or overfed. Frankston suggests adding shredded newspaper, draining the liquid and sprinkling lime, wood ash or dolomite. Ants usually mean the farm is too dry. Add moist cardboard and stand the legs in containers of water.
Hot weather can cause real trouble. Worms escaping hot conditions can drown in the bottom tray. Frankston suggests draining the tray, leaving the tap open and adding rolled newspaper so worms can climb out. On very hot days you can place ice cubes on top and move the farm out of the sun.
A worm farm fits neatly with other small daily habits. Some people pair it with changes like an eco friendly oral care routine. Each step cuts a little more from the bin. Over time those small changes add up.
Frequently asked questions
How many people can one worm farm support?
Brisbane City Council says one worm farm can handle the food waste of two or three people. Larger households may need a second farm. Starting a second one is a simple fix if scraps pile up.
Can I use worms from my garden?
Common garden worms generally cannot cope with worm farm conditions. Use compost worms such as tiger worms, red wrigglers or Indian blues. You can buy them online or from large hardware stores.
Why are my worms trying to escape?
Worms often leave when they are unhappy with the food or bedding, or when it is too hot. Check the temperature and moisture, remove any problem food and add fresh bedding. Move the farm into shade on hot days.
How do I use worm tea?
Dilute it about one part to ten parts water before using it on plants. Redland City Council notes that the strength can be increased as plants get used to it. Drain the bottom tray regularly so it does not overflow.
Advice in this post comes from Australian council guides, and recommendations can vary by region and climate. Check your local council for advice that suits your area.
