4. Crazy compost

By the end of this unit, you will enable children to:

1. Understand the process of composting
2. Learn about the role of microorganisms in the soil and the cycle of materials
3. Learn to sort different materials for making compost
4. Recycle materials for composting
5. Collect organic waste for composting
6. Built a compost bin

Cards illustrating different organisms and environmental factors can be used to help the children learn about and recognise the different factors involved. Drama-based activities can be used to illustrate the work of the organisms in the soil and the interaction between the different elements.

• What's compost? Children from St Barnabas Primary School talk about compost and how important it is! - Fun Kids - the UK's children's radio station (funkidslive.com)
• C is for Compost - Fun Kids - the UK's children's radio station (funkidslive.com)
• Yes-no-maybe-compost-game.pdf (gardenorganic.org.uk)

Pictures showing a variety of everyday waste products can be used to practice the process of 'sorting' waste for composting. The first step is to identify which are organic, and which are inorganic materials:

• Organic materials come from living things, plants and animals. This includes the food we eat, and some of the clothes we wear and things we use - for example those made from leather, cotton, and wool. Organic products all contain an element called carbon which is essential for living things. Many organic materials can be composted quite quickly, but some take a long time to break down and so can't be used in compost - for example cotton and wool (however, they can be re-used and recycled).
• Inorganic materials come from sources which are not living. While some of these do contain carbon, for example diamonds and plastics, they're in a form which can't be easily broken down and used by living things, and certainly can't be used in compost. Many inorganic materials contain useful minerals and perhaps other elements, for example Nitrogen and Sulphur, which we can use in different ways.

The sorting activity stimulates children to consider 'rubbish' in greater detail - so to not think of it solely as one general category (where consideration of the origin and destiny of individual components is ignored), but instead they are guided to 'make categories' for practical use:

• Brown bin: this is best used for raw waste vegetable trimmings left over from food preparation, or tough woody cuttings from the garden and other garden waste. Other organic materials such as cold ashes and tissue paper can be put in the brown bin. Most local authorities have kitchen caddy food waste collections for cooked food, although some will allow this in the brown bin. It is best to check with your local authority what they allow and don't allow in the brown bin
• Recycling bins: for cardboard, plastic and glass
• General waste: for all things that cannot be recycled

Children in the whole school can collect organic produce for composting in each of their classes - for example from fruit snacks. Classes can discuss the guidance on food waste provided by the local authority and other sources. They can then decide which materials to put into the school compost (for example apple cores and some fruit and vegetable peel), and which to put into the kitchen caddy or brown bin for council collection. Guidance for schools on reducing food waste can be found in the Useful Resources.

With the help of the janitors and/or school technicians or parents, children can help build a compost bin for use in the garden.

• What can I compost? | Garden Organic
• GS Compost Lesson Plan
• GS Compost: How to Guide
• GS Examples of compost bins
• Home Composting - a New Zealand Box
• How to reduce waste and recycle at school
• A25-Reduce-re-use-run-around-game.pdf (gardenorganic.org.uk)