How to Make Your Own Worm Farm

How to make your own worm farm

Worms are the world’s best recyclers. They will eat their way through your fruit and vegetable scraps, cardboard, egg shells, paper and even the hair out of your hair brush! Making a worm farm is easy and it is a great way to turn your unwanted kitchen scraps into rich fertiliser for your garden.

What you need

Two polystyrene boxes, such as broccoli boxes. One should have a lid.
A piece of fly screen to fit in the bottom of the box, to stop the worms from falling through.
Bedding material made from a mixture or one of the following: wet shredded paper, dried grass, leaves, sawdust or coconut fibre, plus some compost or soil.
Compost worms. Start with a minimum of 1000.
Something to cover the worms, such as damp cardboard, a hessian sack, carpet or a wet newspaper.
A piece of hose or tubing about five centimetres long.
Fruit and veggie scraps. Don’t use citrus such as orange peel or garlic or onion or chillies.

What to do

Take one box, and using a screwdriver or pen, make air holes in the lid for airflow and holes in the bottom of the box for drainage. Make sure your holes are evenly spaced. The bigger the container, the more holes you will need.
Spread the insect screen in the bottom of the box over the holes. This will stop the worms from falling through into the tray below.
Take the second box and cut it in half horizontally with a sharp knife so that the top box (where the worms will live) fits on top of the box you just cut in half. This smaller box will act as the liquid collection tray for the worm tea that will generate in your worm farm.
Make a hole at one end of the smaller box and insert the hose or tube in the hole for drainage.
Place the worm farm on bricks or wooden blocks in a cool, shady location. Raise one end slightly higher than the other so that the liquid will drain down towards the drainage hose. Place a container below the hose outlet to collect the liquid.
Place a 5 centimetre layer of bedding material inside the main box. Bedding material needs to be moist, but not soggy.
Add your compost worms! Composting worms are different from earthworms and may be obtained from garden centres, large hardware stores or obtained online. Simply do an online search for compost worms Brisbane and you will find a large number of local suppliers who are able to post worms out to you.
A kilogram of worms, the equivalent of around 1000 worms, is a good number to start with and their numbers will increase rapidly.
Place food in one corner of the worm farm and cover with a piece of damp cardboard, carpet, newspaper or hessian to keep worms moist and dark. Worms don’t like light and won’t come to the surface to feed without this internal lid! Add the polystyrene lid to the top to keep out flies and other bugs.
Feed your worms underneath the cardboard or newspaper layer, and give the farm’s contents a stir every few weeks. This helps to aerate the compost and keep the worms healthy.
To harvest your warm castings, stop feeding for two weeks, and expose the open box to sunlight and wait for the worms to burrow down. Using your hand, scrap a layer of castings off the top of the farm. Continue until you have enough castings.

What to feed your worms

Fruit peelings (no citrus products such as oranges, mandarins or lemons)
Vegetable scraps and peelings (no onions, leeks, chillies or garlic)
Cooked vegetables (that aren’t covered in sauce)
Coffee grounds and tea bags
Crushed egg shells
Hair clippings and vacuum cleaner dust

Be careful not to over-feed your worms. Remember, they have little mouths and no teeth! The smaller you chop up the food scraps, the faster they will consume it!

You will know if you have overfed your worms because the farm will start to smell like ammonia. If this happens, stop feeding and stir one quarter of a cup of garden lime through the farm. Resume feeding again once the farm regains a neutral smell.

What not to feed your worms

Bread, pasta or rice
Meat or fish
Dairy products
Left overs
Any food covered in oil, fat or sauce

Brisbane City Council

Rethink Your Rubbish Fact Sheet: How to make your own worm farm