An Earthworm Click to enlarge image
An example of an earthworm. Image: R Mascord
© Australian Museum

When food waste breaks down in landfill it produces greenhouse gas. Instead of throwing it out, start a worm farm. Worms can turn your organic waste into a rich fertiliser that you can use in your garden or potted plants. They can be kept outside, inside, on the balcony or in the garage.

Build a home for your worms

You can buy a worm farm, but you can also build one with boxes. All you need is a box that is approximately 30 cm deep, 60 cm wide and 90 cm long. Styrofoam fruit boxes are ideal. Punch some holes in the base for drainage and to allow air in. Place a tray underneath it to catch any liquid. Cover the box with hessian cloth or jute.

Combine some compost, leaves and shredded paper and soak them in water. Use the mixture to make a 10-15 cm deep bedding layer in your box. Your worm farm is now ready for worms.

Keep your worms out of the heat— make sure your farm is set up in a well shaded spot. You can keep worm farms outside, inside, on the balcony or in the garage.

Get some worms

You can buy your worms from a worm grower or a nursery. They are usually sold by the thousand. Generally, 1000-2000 worms will do for a worm farm. Spread the worms out gently on the surface and allow them to burrow down. Start adding kitchen waste regularly to the box and cover the waste with a handful of soil or compost.

Don’t add too much kitchen waste at once. Wait until the worms have eaten the previous scraps.

Collect worm food

Start collecting your kitchen waste. Mix food scraps with a bit of water before feeding it to the worms. Keep in mind that worms like smaller scraps.

Feed your worms:

  • Fruits and vegetables
  • Crushed eggshells
  • Tea leaves / bags
  • Coffee grounds (in moderation)
  • Leftover breakfast cereals, cakes, biscuits & bread scraps
  • Wet shredded egg cartons, cardboard or paper (non-glossy)

DO NOT feed your worms:

  • citrus fruit
  • uncooked onion or garlic
  • chilli
  • dairy products
  • meat products
  • fish
  • animal droppings

The smaller the food is chopped the quicker the worms will be able to eat it. Worms do not have teeth, they can only suck and grind their food.

Reap the benefits

After a few months, your food leftovers will be turned into a rich, soil-like substance called castings (or vermicompost). Castings are great food for plants. To harvest the castings, move all the bedding to one side of the box and add fresh bedding to the empty side. The worms will move over to the fresh bedding in a few days. You can then remove the old bedding and use it in your garden or house plants.

The liquid collected in the tray under the box is full of nutrients. Dilute this with water and use it on your potted plants. 

Problems? Try these quick fixes!

Worm farming is easy to do. But, a few problems can arise. Here are some common problems and simple solutions to make worm farming a success.

Smelly worm farm?

Your worm farm can get smelly if you feed the worms too much or if the worm farm is too wet.

Quick fix

Feed your worms slowly and only when they have eaten the previous scraps. Make sure that the worm farm is well drained. Add holes in the base if necessary. If it is too wet, your worms may drown.

Little critters?

Some insects like ants, cockroaches or vinegar flies may find your worm farm inviting. They may be a bit of a nuisance, but not to worry, they won’t harm your worms.

Quick Fix

Keep your farm covered with hessian cloth or jute. If your worm farm sits on legs, place each leg in a bowl of water. This will stop any intruders from getting in. If you have vinegar flies, your worm farm might be too acidic. Just add some lime, dolomite or wood ash.

Worms not breeding?

Worms are very particular about their environment and will only breed in the right conditions—cool temperatures of 18-25 degrees celcius, moist but not too wet, shaded and not too acidic.

Quick fix

Keep your worm farm in a shaded spot, keep it covered and make sure is has good drainage. Add some lime, dolomite or wood ash to prevent the worm farm from becoming too acidic.

Going on holidays?

Unlike other pets, you can leave worm farms unattended for weeks at a time.

Quick fix

Worms will happily eat paper for up to 6 weeks! Just shred and wet the paper first so that the worms can eat it more easily.

Worms are escaping or dying?

The worm farm conditions might not be suitable for your worms. They might not have enough food or the farm might be too dry, too wet, too hot or too acidic.

Quick fix

Depending on the problem, either add more food, moisten the bedding, mix in some shredded cardboard or paper to absorb moisture, move your farm to a cooler location or regulate acidity with lime, dolomite or wood ash.