Home Composting

Why compost at home?

Much of our domestic rubbish ends up in landfills - big holes in the ground. A lot of this rubbish is ‘organic matter' - vegetable peelings, garden waste, cardboard and shredded paper. Landfill sites are squashed down and over time the organic matter is converted into methane gas which is implicated in climate change. We are also running out of large holes in the ground to put our waste into - we're going to have to learn how to reduce, reuse and recycle the waste we send to such sites.

Home composting allows you to stop sending a lot of this organic matter to landfill and can also provide you with a superb soil additive for your garden and growing medium for your houseplants. Helpful microbes and worms work together to break down the nasty organic matter and turn it into lovely dark rich compost that is pleasant to handle and full of nutrients. All you need to get started is a place to keep your compost.

Heaps or bins?

Whilst you can just heap garden waste, vegetable peelings and the like into a big pile in the corner of the garden in order to make compost, most people prefer to make their compost in bins. A compost bin keeps the compost looking tidy and can help the compost ‘heat up' to speed up the process. You can build a bin yourself out of scrap wood or you can buy bins made from recycled plastic. The latter are available from DIY stores and often discounted via your local council - either get in touch with your local recycling officer or take a look on at this website: http://www.recyclenow.com/compost/

Batch or continuous?

If you have a large amount of material available in one go you can make compost in batches - ideally around a cubic metre (35 cubic feet) of material at once. This might be the case if you have a large garden or an allotment plot. Batch processing is often best done in wooden compost bins that you can either buy or make from scrap wood.

However, if you've got a smaller supply (for example just veg peelings from the kitchen, some grass clippings, hedge prunings and shredded paper and cardboard) you can make compost on a continuous cycle - you put your material in the top of a bin and take the finished compost from the bottom. The plastic bins available from your council are ideal for this and fit into even the smallest garden.

Mix and match

Home composting is easy, but there are a few rules to make it work better and eliminate the chance of nasty smells. The organic matter that you put into the bin is split into two categories: ‘greens' and ‘browns'. The greens are the soft, wet material such as veg peelings and grass clippings that are rich in nitrogen which will help your plants grow once it is in your compost. However, if you try to make compost entirely from ‘greens' you will find that you attract the wrong sort of microbes and it will get slimy and smelly.

‘Browns' on the other hand are materials with lots of carbon in them. Examples are twigs, sawdust, torn up cardboard and shredded paper. If you try to compost just ‘browns' it will not smell but it will take a long time - several years at least.

Ideally you need to have a mix of both ‘greens' and ‘browns' in your compost bin. The easy way to achieve this is to put a layer of twigs at the bottom of your bin to help the air to circulate, and then alternate layers of ‘greens' and ‘browns'. The contents of the bin should be just moist. If you're feeling really keen you can even pour human urine on the heap - it is sterile and will help ‘activate' the composting process!

If you get the mix right you should find that the contents of the bin start to heat up. This is a result of the microbes busily working away to digest all the material you put in it and turn it into compost. If you're adding material constantly to the top of the bin, you'll find that it magically shrinks down to make room for more. In the plastic bins you can buy there is usually a door at the bottom that you can use to dig out the finished compost.

Problems?

Home composting is easy and rewarding but occasionally people find things go wrong. Here are some common problems and solutions:

1. My compost bin is smelly! The chances are you've got too many ‘greens' in the bin - pop in a one- to two-inch layer of ‘browns' such as twigs, torn up cardboard or shredded paper and give the bin a stir with a garden fork. You should also ensure that your bin is not standing on concrete or paving stones - it needs to be on some earth so that excess water can drain away and the worms can get in.
2. The bin is filling up and doesn't seem to be doing anything! You might have too many ‘browns' in the bin - try stirring in some ‘greens' such as grass clippings, leafy vegetable waste or kitchen peelings. In the winter you'll also find that composting often slows down. Don't worry - it will speed up in the spring!
3. There are loads of flies, woodlice or worms in the bin! You will get worms in the bin - this is a good thing! You also sometimes get fruit flies or woodlice in the upper layers. If these become a problem cover veg peelings and fruit skins with a layer of ‘browns' and/or some garden soil.
4. I don't have room for a compost bin! Some of the plastic bins available via your council are actually quite small and can fit in behind bushes or sheds in even a small garden. If you don't have any garden at all, you might find that a wormery is an alternative for dealing with kitchen scraps - see the Idea Sheet on wormeries for more details.

What can go in the compost bin?

Greens:

• Raw vegetable peelings
• Fruit skins and cores
• Grass clippings
• Annual weeds (speedwell, daisies, etc)
• Wool, cotton and other natural fibres

Browns:

• Twigs and hedge prunings
• Torn up cardboard
• Shredded paper
• Scrunched up sheets of newspaper
• Eggshells
• Straw and hay (and bedding from vegetarian pets such as rabbits)

Do NOT include:

• Non-organic matter - plastic, metal, man-made fibres
• Roots of pernicious weeds such as dock, couch grass and stinging nettles
• Droppings from carnivorous animals such as dogs and cats
• Cooked food remains
• Dairy products, bones and fat.

The latter three items can be processed in a special composter designed to handle them - several of these are available commercially (for example the ‘Green Cone'). The main reason for not adding them to the normal bin is that they can attract vermin (rats and mice).

Happy Composting!