A compost bin (or compost heap) provides a home for millions of living creatures, (most of these are too tiny to see without a microscope!) and it’s these mini beasts that turn the materials in the bin into rich soil-like compost. Like any living creatures they need food, water, air and shelter to survive and be healthy. Let’s start off with creating the shelter…
Shelter - Setting Up Your Compost Bin
Your compost heap/bin should ideally be:
• Placed in a partially sunny spot to help speed up the process
• In an area that is well drained to allow water to soak away
• On soil so that worms can get in and help break down the contents
You now know where to put it you waste, but what type of ‘bin’ is best to use? There are many types of compost bin available to buy, alternativly you may like to create a school project with the aim of building a class bin. Visit our ‘Composting Systems’ page to help decide what set up would be best for your school.
Food - The Composting Recipe
Making good compost is a bit like making a cake! You need to get the recipe right to get the best results! Just follow the ingredients list below to make sure that you get a good balance of ‘greens’ and ‘browns’. The items listed are examples of materials that schools may already have that may be currently going into the school waste bins? To get healthy compost (and avoid a slimy mess infested with fruit flies) you need to add ‘brown’ materials (see below) each time you add your 'greens'. Fruit and vegetable waste. The ratio needs to be about 50:50. Here are a few greens and browns you may have at your school:
|Uncooked fruit/ vegetable waste
|| Torn up thin cardboard
|Tea bags & coffee grounds
|Plants and flowers (avoid weeds)
||Egg boxes (cardboard)
Schools tend to have lots of ‘greens’ (especially fruit and teabags from the staffroom) on a daily basis and less of the ’browns’. This is the main reason school compost bins are often very wet and sloppy and full of fruit flies. So it is worth storing up shredded paper and cardboard etc. (ask the caretaker nicely!) so you have a supply to keep adding. If possible, collect thinner cardboard such as toilet roll tubes, egg boxes and similar packaging. You can also use scrunched up paper towels and newspaper. You could try putting a plea in your school newsletter asking parents for these ingredients if you don’t have a regular supply in the school.
But of course there are many other things you can compost Here is a more detailed list to help you.
If you have the right mixture of materials you shouldn’t need to add any water. If your bin does look a bit dry (ants in the bin is a good sign of this) its best to add more ‘greens’ which contain a lot of water but you can add water (ideally from a water butt) if necessary.
The microbes and mini-beasts in the bin breathe air and if they do not get enough they will die. By adding scrunched up cardboard and other “browns” you create air pockets in your bin. Turning the compost from time to time with a garden fork, or simply sticking a broom handle into the bin and wiggling. This also helps to make channels of air but you don’t need to do this very often.
Once it is ready…
It will take around 9 to 12 months for your compost to be ready at this point it should look brown and crumbly, just like soil. You will probably need to sieve it to remove larger bits which haven’t quite rotted enough but you can put these back in the top of your bin and try again.
An easy way to empty the bin is to place a sheet of plastic on the ground next to the bin and using a garden fork or spade remove any unrotted materials from the top of the bin onto it. Then lift the bin and the finished compost can easily be removed and put into a wheelbarrow or straight into old fertiliser bags to store and use later.
Next, put the bin back to its original position and put the unrotted materials back inside and you are ready for the next load.
The finished compost can be put on the soil around plants. You can dig this into the soil for growing vegetables or put in a layer on top of your school planters where it will feed the plants and reduce water loss.
Finally, give yourself a good pat on the back, well done, you’ve made your first compost!