How to make vermicompost

First started in the US in the 1950s, vermicomposting is now a popular practice around the world. It involves using worms to create your own home ecosystem which works tobreak down organic material.When carried out under the right conditions, vermicomposting should not produce any unpleasant odours and you should end up with rich compost that can be used around the garden or vegetable patch.

There are a number of different containers – wood and plastic – that have been specially designed to make vermicompost. The most commonly found are vertical vermicomposting bins made up of 2, 3 or 4 layered trays, (which may also be referred to as drawers).

These trays must be opaque as worms do not like the light. The base of the trays must feature a series of holes to allow the worms to move around. The lowest tray does not have any holes but it is equipped with a tap which allows you to collect the concentrated liquid that seeps out the bottom (this is known as leachate).

A vermicomposter with 3 trays measuring 60 x 60 cm will be perfect for processing the waste of a family of four.

1. Set up your vermicomposter

Place your vermicomposter, or worm bin, in a quiet area with a relatively even temperature of around 15 to 25°C (ideally 20°C). Luckily, this is about the same temperature as our homes so you can place your box in the kitchen, in a cellar, basement or even in a cupboard!

If you want to set up your vermicomposter outdoors – on a balcony, for example – be sure to keep your bin far away from any spots that reach over 30°C in summer or sub-zero temperatures in winter.

2. Preparing your vermicompost bedding

Line your tray with about 2 to 3 cm of bedding. If your worm supplier hasn't provided you with any, you can make your own using old newspaper, pieces of cardboard or some coco fibre that you have moistened in advance (it should release just a drop of water when squeezed).

3. Add your worms to the bedding

Introduce your worms to the first layer of the box using the bedding they came with. Your worms must weigh twice as much as they amount of waste you place in the box. So if you plan on placing 300 g of waste in your bin every day, you'll need 600 g of worms to get started.

Do not use earthworms from the garden: these worms are great for other things but are not at all suited to making vermicompost. You'll need to source your worms from a compost supplier, a fishing shop or from their natural habitat.

4. Wait a few days before your first waste deposit

Your worms will need a few days to get used to their new environment.Be patient and wait three to four days before adding your first vegetable scraps.

5. Start adding your scraps

Add a small amount of food waste at first (a handful of peelings or one of two banana skins will do) and wait for a few days.

6. Gradually increase your food waste deposits

Continue to feed your bin with small amounts of kitchen waste, gradually building up to reach the maximum amount of waste allowed by your bin. It's up to you to manage the amount of waste you add to the bin. You should reduce the amount of waste if it is not being eaten as this can lead to unpleasant smells. Similarly, it may lead to your waste fermenting and raising the temperature of the bin which will kill your worms. Cut up any large scraps.

Add a little newspaper or pieces of cardboard from time to time for a source of carbon. Worms reproduce quickly and regulate themselves. If you plan to be away from a few weeks, ask a friend to feed your vermicomposter.

Your compost should be ready to collect after around three months when it has turned brown in colour.

Stop feeding the tray and layer on a new tray which you will now fill with waste instead. The worms will be attracted by the new food and climb through the holes to the upper tray.

Once all your worms have migrated, you can then collect the compost from the lower tray.

Wait a few more months and add another tray on top of the second one you added, collecting the compost from the second tray. Your worm bin is essentially a rotating system.

Rich in microorganisms, this type of compost should be used quickly and shouldn't be stored for months on end.

You should only use well-matured vermicompost.Mature compost is created when all waste has been transformed into an even substance that is black or brown in colour. It can be spread around the garden, sprinkled thinly over soil or used for potted plants by creating a mixture made up of one quarter vermicompost to three quarters soil.

The leachate gathered from the bottom tray is a very nutrient-dense liquid that can be diluted to a tenth of its strength and used to water your plants.