I visit a lot of schools who like the idea of a compost bin and have one, but in terms of really using it, are a little unsure about what they are doing. The trick is to prepare in advance. Composting is not a spur-of-the-moment activity for a supply teacher.  However with a little thought it makes a great project and practical activity for a class.

Firstly, whether you are a teacher, parent or interested person, try and download the Little Rotters Handbook. It has lots of clear information aimed at teachers who wish to introduce a compost system into their school. Sadly the Little Rotters website is no longer live.

Next, it’s perfectly possible to have a “leave it to rot” compost system. This is slow and can be prone to going a little wonky. It’s important to have a mixture of fruit and vegetable peelings going into the bin alongside scrunched up paper and dead plant material such as stalks and stems. Have 3 compost bins going at once. The first bin is filled in term 1, the second in term 2, the third in term 3. Leave the compost in each bin for a year to break down before using. Remember to turn it occasionally or poke it with a stick to keep it aerated.

At home I have 2 systems happening at once. Firstly I have my “dump it” compost bin. This is where I chuck my fruit and vegetable peelings along with a bit of cardboard, weeds and other compostable matter. Some gardening books will warn you not to add perennial weeds as they will simply grow again from the compost made. Because I tend to use mulch this doesn’t especially bother me.

The bin on the right is my “dump it” bin. The bin on the left is my layered compost bin where compost is created more quickly. Both are situated in the darkest corner with the most shade in my garden
The real satisfaction comes from my second bin. This is the one which takes more time and organisation but is much quicker and effective. Here’s how it’s done…

Have plastic sheets ready for the matter needed to make a compost bin or heap
First, begin to gather a selection of compostable material. This includes the compostable matter in my “dump it bin”.

Ideally even the fruit and veg peelings should be chopped up, but I’m inherently lazy!
Then begin collections of other material. This time I had…

Straw that was part of a postal delivery of some child-size gardening tools.

What a great idea for a packaging material!
Shredded paper. I get a real kick out of composting old bank statements!

I add this direct from the shredding bin
Dead shrubby material from the winter clearance. My hop plants, dead stalks and plant matter.

I kept this in a pile in a corner of my garden for a few weeks. It makes a good wildlife home in itself so try and have lots so that not all needs to be composted.
Grass cuttings from last year. I hate to throw this in the bin or even take it to the recycling facility. I like the permaculture approach of trying to re-use everything within the garden itself.

This is the small pile left after creating the second layered bin. It will be all gone shortly once the composting process begins and the amount in the bin decomposes
The above materials are layered inside the other compost bin. Basically it’s an alternate layer of fruit, vegetable and grass matter with the paper, straw and dead plant material.

Here it is, all full up! In a few weeks it will be reduced to half the volume! Amazing!
I tend to add a few layers of nettles or comfrey to activate the compost bin too. I have low growing comfrey in my garden which is great for adding to the compost heap and keeping the bees happy when it flowers. Finally, adding a piece of carpet to the top, can help too, but it still works fine without this.

Comfrey is one of the most useful and versatile plants that will grow in Scotland. Get some now!
A good compost check is to see how it smells and what’s in it. Basically a happy compost heap doesn’t reek. It will have lots of worms and the breakdown process is evident. It will not be too wet or too dry.

Oops! This one mings!
In an unhappy compost bin, you might get lots of flies, a bad smell and few worms. After a while you work out which material takes too long to decompose. In my compost bin large fruit stones such as mango and avocado tend not to rot quickly. Egg shell doesn’t either but I just crush this down.

This is my “dump it” bin. Because I tend to aerate it through digging it through, it tends to be quite happy even if the decomposition rate is slow.
Most local authorities have cheap or free compost bins that have been tried and tested in the local area. However I like the bin below. This was in a Swedish I Ur och Skur nursery. An acetate panel has been inserted so that children can see the decomposition in action. It’s also possible to do a mini compost bin in a plastic bottle. This is a useful activity to create interest and also to send home so that children can explain what composting is to their parents and carers. Instructions can be found on the Carry on Composting website.

Below is the “hot composting” system at Inverary Primary School. The janitor is a keen gardener and oversees this operation. Basically it’s not dissimilar to the layering system, except the compost is turned more easily in these containers.

Again, to have a hot composting process, there needs to be a storage system for waste material so that it can be added in the correct mix and quantities. Inveraray Primary School have a whole shed dedicated to this! Wow!

Below, is an example of a keyhole composting system from the Cruikshank Botanic Garden in Aberdeen. The name comes from the design. If you look at the brickwork, there is is a gap which allows you to walk into the centre of the feature and deposit your waste matter into the central compost ‘bin’.  As the waste matter breaks down, nutrients and water feed the surrounding raised bed where vegetables can be planted. Lots more information can be found online about this compact method which is common in arid countries but increasingly becoming popular everywhere as it can be made entirely from recycling materials such as old bricks and rocks to create the design.

Keyhole compost bin

In the corner of the Saules Gojus school in Lithuania, I saw another different approach. The garden waste and vegetables and fruit are put in one dark corner of the grounds. Everything is left to rot down. Melons are planted here every spring so that the compost heap becomes an informal raised bed.

SG Compost heap

 As with most outdoor and gardening matters, trial and error is an important part of the process. It’s a matter of finding the right composting container and system that suits your own and the children’s needs within the climate and setting that you live and work.

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