Build a wormery

How long will it take?

Half an hour to set up and several weeks of observation.

What you will need

• a large, clean, glass jar
• moist soil
• sand
• earthworms
• old leaves
• vegetable peelings, tea leaves, overripe grapes
• some black paper and a cool, dark cupboard

Step-by-step guide

1 Ask your children to cover their work surface with newspaper. They will need to wash their large jar carefully so that it doesn't smash. You may want to help younger children with this.

2 Help your child to put a layer of sand at the bottom of the jar, about 1cm (0.4in) deep.

3 Add a thick layer of soil, then add another thin layer of sand, then another thick layer of soil. Ensure there is about 5cm (2in) of space at the top.

4 Now for the fun part! Ask your children to go and find some worms. Before they put them in their jar, ensure they have a good look at them. Can they tell which end is which? How? Can they guess how a worm moves? Can they see the hairs on the worms skin?

5 They need to put the worms in their jar, then add some old leaves, vegetable peelings, tea leaves and overripe fruit if you have any.

6 Then they can put the lid on - with a couple of holes in the top - place black paper around the jar and put it into a cool, dark cupboard. Leave it for about a couple of weeks and then observe what the worms are doing.

7 What has happened to the vegetable peelings?

8 What patterns have the worms made in the earth?

Tips and advice

• Your children are likely to find this project much easier to do than you are! Do try to overcome any squeamishness, as worms are so vitally important for the gardener. Not only do they aerate the soil and improve its condition by breaking down rotting plant waste in the soil, they will also produce even higher quality compost in your compost heap, eating their way through quantities of kitchen waste at the same time. When children are collecting and observing the worms, they need to be aware that worms do not like to be in the dry or the light for any length of time. They could try holding them on wet hands, or looking at them on black paper (not as easy to see them), or using several, each one just for a few minutes.
• Your children may wish to investigate the two main types of worm (earth and tiger). They can set up two jars and compare what happens in them. This is an important scientific skill, which will be developed in school.
• Always ensure the contents of the jar are moist, not too wet and definitely not too dry. Worms 'breathe' through their skin, which must be damp for this to happen. The jar should not be put anywhere too cold.
• There is no danger with this project, apart from when handling the soil, and your children should be vaccinated against tetanus already. Worms do not bite or produce any skin irritant.
• Charles Darwin studied worms for 39 years, and concluded that life on earth would not be possible without them. Mainly because they increase soil fertility so efficiently, but also because they reduce quantities of plant waste.
• Brandling worms - also called tiger worm, or Eisenia foetida - will come naturally into your compost heap, but you can make your own wormery to process kitchen waste more quickly and efficiently. You can give the worms most kitchen waste - all uncooked fruit and vegetable waste, tea leaves, coffee grouts etc. In fact, worms are omnivorous and can eat meat as well, but it is sensible to keep this out of your jar, wormery or compost heap.When the contents of your jar look well mixed, the vermicompost (compost produced by worms) is ready to use.
• Earthworms are what you will find if you dig in your garden; tiger worms are what you will find in your compost or manure heap, or you can sometimes buy them in an angling shop. Use one or the other.