Composting for schools

Information sheet

All around us an amazing process is continually taking place. Organic waste, such as plant material and dead insects are converted by millions of bacteria and micro-organisms into crumbly compost.

  • School term: All year round
  • Level of experience: No experience needed
  • Subject(s): Science, Geography

Composting is a process to turn garden and kitchen waste into a free, environmentally friendly source of organic matter, which can be put back on to your garden, improving the soil and conserving moisture. It also helps reduce waste disposal of if green waste isn’t collected as part of your waste collection service. 

Types of composters 

The simplest way to compost material is to pile everything in a heap and cover with sheets of cardboard. Most people use a container of some description. This not only looks neater but also helps to deter vermin. It is easier to manage and speeds up the composting process by keeping the heap insulated. 

  • Stationary composters
  • Tumbling/Rotating composters
  • Worm composters
  • In-ground worm composter
  • Food waste digesters

You will find that a wide range of containers are available on the market and some local authorities will provide cheap bins for people who live in the area. You can also make compost bins from old wood and pallets. Three is the ideal number to allow you to 'turn' compost from one bin to another. This mixes and adds air to the contents which in turn provides better quality compost.

Siting your compost bin

Make sure that your bin has an open bottom and is placed on a soil base. Try and dig the area beforehand. The open bottom allows moisture to drain away and gives access to soil organisms important to the process of composting.

In colder areas of the country a sunny site will encourage composting during cold weather whereas in hotter, drier areas a shady spot will help to prevent your heap drying out. If there is a prolonged dry spell of weather it is a good idea to add extra water to the compost heap to stop it drying out.

Remember to allow good access to your bin for emptying and space for wheelbarrows to fit comfortably nearby.

Which materials can be added to the compost bin?

Aim for 25-50% of green waste: Flowers, fresh leaves, grass cuttings, annual weeds, fruit and vegetable waste and plant material.

Aim for 50% plus of brown waste: Chopped up twigs, dried or old leaves, hedge trimmings, bark, tough plant stems, straw or hay, shredded paper and cardboard, eggshells, sawdust, newspapers and brown paper bags shredded.

How to keep your compost happy 

  1. Avoid allowing any one material to dominate your compost heap such as grass clippings or fruit waste. This can make your compost slimy and smelly. If this is the case, turn your compost and add more brown material.
  2. Flies can be a problem, especially in high summer. Try covering your compost heap with shredded paper.
  3. Discourage vermin (mice, voles and rats) from your compost heap by only adding garden and vegetable material. Never add cooked food or dairy waste to a compost heap. Call in the professionals if there is a rat problem.