How to make Compost

Information and advice about making compost heaps and using compost bins

Jump to :-      How much space do you need?   |   Do you need a Compost bin? 

Where to put a compost heap  |  What you can & can't compost  |  When and how to start a Compost Heap  |    How long does it take and when is compost ready to use?

Just as we need to re-stock our store cupboards or fridge with food in order not to starve, so it is with replenishing the soil in which we grow our vegetables or fruit. Although fertilizers can play a large part in growing edible crops, adding bulky material which is full of nutrients is essential to maintaining the soil structure and growing healthy crops: it’s the difference between taking only pills to get your vitamins or eating fresh fruit and vegetables.

Buying compost is an option, however if you have anything more than a  2m/6ft sq plot, then you can save a fortune by making your own compost. Even if you are growing crops in a number of containers, you will need to replenish the compost every year, so it is probably still worth making your own compost if you have the space.

This article will explain what you need, how to start a compost heap and how to look after it to ensure you have lots of excellent garden compost for use in your vegetable plot, fruit garden or containers.

How much space does a compost heap take up?  

In theory, compost heaps can be as large or as small as you like however, in practice if it’s too large it may become unmanageable and if it’s too small it may not generate sufficient heat to break down the vegetation properly in a reasonable time. So in general, the optimum size is around  90cm/3ft.sq (or diameter) and up to 120cm/4ft deep, which can be built up over time if necessary. If you have a lot of material to compost, then it’s easier to have two or more compost heaps on the go at the same time so you can be using the compost from one whilst the others are maturing.

Do you need a Compost bin?  

There are many compost bins available on the market: from simple wooden structures to fancy plastic ones. Whilst it’s not absolutely necessary to buy a compost bin, they do help keep the compost material tidy and compact which helps keep the heap warm and so aids the breakdown of the composting material. This also speeds up the process so the finished compost will be ready to use sooner.

Where to place a compost heap  

Whether you are using a bin or not, ideally the compost heap would be in a relatively  sunny place either on bare soil or on concrete or other hard standing material,  in a place where you can easily add ingredients and remove the finished compost for use in the garden or plot. Whilst traditionally, they were placed right at the back of the garden out of site, today’s compost bins are by no means unsightly and as the finished product should be rich, dark, crumbly and sweet-smelling, there is no reason why it shouldn’t be near the house, especially as  certain types of kitchen waste can be used. 

What to put on your compost heap  

There are many things which can go on the compost heap, but the trick is to add both quick rotting material which serve as activators and get the process going, and slower rotting materials to give the compost more substance and a good texture.  The only additional component needed is moisture, although the heap only be watered when very dry.

List of what you can compost

Garden waste – anything which has grown in the garden can be composted apart from diseased plants and leaves, including grass clippings, fallen leaves, stems, edible parts such as fruit or berries, woody stems and roots. As mentioned above, it’s best to have a mixture of different types of material. Grass clippings and fallen leaves in particular, should never make up more than a 5cm/2-inch layer between other materials. Very woody items should be broken or preferably shredded down to very small pieces.  

Kitchen waste – items such as raw vegetable peelings, crushed egg shells, tea bags and leaves and coffee grounds   Animal manure and beddings -  from herbivores only such as cows, horses, rabbits, guinea pigs  

Other materials - Wood ash (in moderation), hair and nail clippings, cardboard such as scrunched up cereal boxes, shredded paper such as junk mail or confidential papers, sawdust and wood shavings

List of what you should not compost

Do NOT compost

• Meat or poultry  (raw or cooked)

• Fish (raw or cooked)

• Cooked food of any kind – even vegetables

• Coal or coke ash

• Cat litter

• Dog faeces

• Disposable nappies

When and How to start a Compost Heap  

Although you can start a compost heap at any time, it's best to start when the weather is still relatively mild. Autumn is a good time to start, particularly because there is likely to be more garden waste available.

At its simplest, you need do nothing more than just add waste material as and when you have it. However, its best to wait until you have enough material to create a layer of at least 30cm/1ft at a time – more if you wish. You can also add all the  material right at the start to completely fill the compost bin (or build up the heap), cover with the supplied lid, polythene sheeting with 2.5cm/1-inch holes every 30cm/12”, or a permeable material such as hessian sacks, matting or even a good layer of straw,  then just leave it to rot down.  

Better results can be achieved with just a little more effort in the form of turning the heap just once or twice during the composting process which not only mixes everything up, but adds air to the mixture which speeds up decomposition. If you have the energy, heaps can be turned once or twice a month which is even better.   Simply remove the lid or other material you’ve used, if using a  compost bin, remove the contents and if  the lower layers have already composted you can use this in the garden,  then mix everything up well, water is necessary (or allow to dry out  if it’s very wet) then return to the heap/bin and re-cover.

How Long does it take to make compost and when is compost ready to use?

Whilst compost can be ready in as little as 3 months, it usually takes 9- 12 months or more for a whole heap to compost down but remember, in general, the more effort you put in, the quicker you will get compost.

It is also likely that the materials at the bottom will be ready before the upper layers so having a compost bin which has sliding access to the bottom part is very helpful.  

Once the materials you have put in your container have turned into a dark brown, earthy but sweet smelling material, the process is complete however it is then better if you can  leave it for a further month or two to mature before using it.  

Don't worry if your finished compost is a little lumpy or has bits of twig or eggshell still showing, it is perfectly useable and if you wish, you can always remove larger bits and start another compost heap with them although this isn’t necessary.