A typical household’s waste is around 40% organic matter. Things like fruit and vegetable scraps, food scraps, tea bags and coffee grounds. All this can be recycled by worms and turned into beautiful, rich, chemical-free compost which you can use in your garden or around your potted plants. Keeping this organic matter out of landfills would not only reduce the volume of rubbish sent to landfills but also reduce methane, a greenhouse gas which contributes to global warming.

Once you’ve finished the initial set up of making your worm farm it’s just a matter of collecting your organic matter in a separate container and dumping it in the worm farm instead of the rubbish bin. You’ll be helping the environment and in exchange getting a valuable product that your plants will thrive on. And aside from the one-time set up and occasional harvesting, the worms do most of the work.

How a worm farm works

• The worm farm is housed in a bin, or more exactly, a series of stackable bins lids. You can make your own from a variety of materials or buy a ready-made kit, usually made of plastic, which often come complete with worms. The worms start off at the bottom unit. As organic waste gets added the worms eat their way up through the bins, leaving worm droppings, also known as ‘vermicast’ behind them. The vermicast is a very rich, top quality compost that can be used in your garden or potted plants.

• At the bottom is a collector tray. The second by-product of this process is a liquid, which is sometimes called ‘worm tea’ or ‘worm wee’. This liquid makes a fabulous liquid plant food when diluted with water in a ratio of 1:10 (1 part liquid, 10 parts water). The worm farm kits usually have a spigot on the collector tray to make it easy to drain off the worm wee.

• You add organic waste. You add organic waste in the form of kitchen scraps, leaves, grass clippings, shredded paper. As the worms eat half their bodyweight a day, turning their food into compost, the layer of compost beneath them builds up and they literally eat their way up through the bins.

• When the worm farm is almost full, harvest the vermicast. When the bottom unit has filled and all of the worms have moved up into the units above, you remove the bottom bin, and the next bin up now becomes the bottom bin. You can use the compost to as a natural fertilizer, top-dressing or mulch in your garden or containers.

What composting worms like

• Dark, moist (but not wet) living conditions.

• Constant temperature range. Position the worm farm to avoid direct sun for any length of time, or high temperatures. If you live somewhere with cold winters use an insulation jacket over the bins in the winter.

• Good air circulation. Take care to not overfill the bins with waste material.

• A mix of dry and wet waste. If your fruit and vegetable scraps are too wet, mix in some dry material such as shredded paper or egg cartons, or toilet roll cores, dust from sweeping or the vacuum cleaner, hair clippings.

What composting worms don’t like

• Too much water. If their environment is getting too waterlogged make sure you drain off the liquid at the bottom and add more dry material like shredded paper and egg cartons or cardboard.

• Too much acidity. Some foods, like onions, garlic, lemons make the environment too acid, so go light on those foods.

• Too much waste material above them. Even though the worms can burrow underground they still need air. If you have too much waste above them, especially if it’s getting damp and packed in, it can cut off their air supply and the worm farm will start smelling bad. If you have large scraps like lettuce or cabbage leaves chop them up and mix with shredded egg cartons or cardboard to keep the waste light with lots of air spaces. If you have more waste than the worms can keep up with you can put the excess in plastic bags and freeze it. Then defrost and use it when the worms need more food.

What can be composted?

• Food scraps (except meat, fat and dairy products)

• Grass clippings (in moderation, too much can clump together and cut off the air circulation)

• Leaves

• Seaweed

• Farm animal manure

• Untreated sawdust and shavings

• Vacuum cleaner dust and floor sweepings

• Hair clippings

• Shredded paper and cardboard (avoid glossy paper such as that found in magazines)

As long as you provide the right conditions, regularly feed them and drain off the liquid, your worms on your worm farm will continue eating, breeding and providing you with the best natural fertilizer for your garden and plants.