Composting is good for the environment and good for your pocket. It allows us to recycle household waste into nutrient-rich soil, it reduces waste going to landfill and so is good for the environment; and since you won’t need to buy fertiliser and bags of compost from the shops it is also good for your pocket.

Read more about why we should compost, how to compost, and how to decide upon what type of composter to use.

Why we should compost

  • Composting saves money. Home composting:
    • Means you don’t need to buy fertilisers – compost is free.
    • Helps water retention and so helps reduce your water bill.
    • Saves on car trips to rubbish dumps and so reduces your fuel bill.
    • Reduces civic costs for waste collection.
    • Extends the life of landfill sites – 40% of residential waste is compostable.
  • Composting has environmental benefits:
    • It keeps a valuable resource out of landfill.
    • It enables us to return valuable nutrients to the soil.
    • It improves the soil texture and air circulation.
    • Composting produces carbon dioxide. Organics in landfill create methane. Methane is 21 times more harmful for the environment than carbon dioxide.

How to compost

Composting is like cookery. When you cook a meal you:

  • choose and prepare the ingredients,
  • place them in the pot in the correct proportions,
  • leave the pot to cook (stirring occasionally of course), and
  • serve up on plates to your guests.

Composting is the same. When you compost you:

  • choose and prepare the ingredients by separating out compostable from non-compostable items,
  • add them to the compost pile in the correct proportions,
  • leave the compost pile to cook (stirring occasionally of course), and
  • serve up on a wheelbarrow to your beds and borders.


The first phase in composting is separation which involves splitting out compostable waste. Anything that was once living – organic matter – will compost but some items are best avoided. As a rule of thumb you:

  1. Cannot compost inorganic matter such as tin foil, plastics, glass, metals.
  2. Can always compost uncooked and unprocessed vegetable matter – fruit, vegetables, grass clippings, plants and leaves.
  3. Can sometimes compost processed vegetable matter – such as paper, cardboard.
    • For these items it depends upon how the item was made. E.g. shredded newspaper can be recycled but a glossy magazine cannot.
    • Degradable does not mean biodegradable. So do not compost degradable carrier bags.
    • Compostable packaging can be composted with care at home but not at a communal composting facility.
  4. Can theoretically compost small quantities of animal matter – meat and fish, fats and oils, dairy products. But this should be done with great care and our advice is to avoid these, at least at first.
A clear explanation of the principles underlying the “separation” process.


The second phase in composting is placement which involves adding compostable items to the pile in the correct proportions. Some things, like grass mowings and soft young weeds, rot quickly. They work as “activators”, getting the composting started, but on their own will decay to a smelly mess. Older and tougher plant material is slower to rot but gives body to the finished compost – and usually makes up the bulk of a compost heap. Woody items decay very slowly; they are best chopped or shredded first, where appropriate.

For best results, use a mixture of types of ingredient. The right balance is something you learn by experience, but a rough guide is to use equal amounts by volume of “greens” and “browns”.

Greens are nitrogen-rich:

  • Grass cuttings
  • Young weeds
  • Nettles (not roots)
  • Comfrey leaves
  • Urine (ideally diluted 20:1) – this ingredient is not obligatory!
  • Uncooked fruit and vegetable peelings
  • Tea bags (Many teabags contain small quantities of plastic. Ideally empty bags first and use only the leaves on the compost.) Tea leaves and coffee grounds
  • Soft green prunings
  • Animal manure from herbivores eg cows and horses
  • Poultry manure

Browns are carbon-rich:

  • Cardboard eg cereal packets, toilet roll tubes and egg boxes
  • Waste paper and junk mail, including shredded confidential waste
  • Paper towels & bags
  • Bedding (hay, straw, shredded paper, wood shavings) from vegetarian pets eg rabbits and guinea pigs
  • Tough hedge clippings
  • Woody prunings
  • Old bedding plants
  • Straw
A detailed and clear – if somewhat leisurely – explanation of how to mix greens and browns.


Add the items to your composter and leave it to cook. You can continue to add to the composter whilst it’s cooking – that’s not a problem.

The third phase in composting is management of the composter, since in addition to the organic material – the greens and browns – a composter also needs a supply of air and water.

Add the items to your composter and leave it to cook. You can continue to add to the composter whilst it’s cooking – that’s not a problem.

An ideal composter is:

  • No smaller than 1m x 1m x 1m – any smaller and items may not compost properly,
  • No larger than 1.5m x 1.5m x 1.5m – any larger and the pile becomes hard to manage.

Cooking takes 6 to 10 weeks (sometimes a little less, sometimes a little more) and the time depends upon what you’ve put into it and the time of year.

Each week or fortnight you will find that the middle of the composter has become very hot and material has already started to break down but the material on the outside hasn’t. At this stage you “turn” the material in the composter – basically mix it all up, introducing air into it – and water it.

Choosing A Compost Bin System

You don’t need a lot of space or money to compost at home. When choosing a compost bin, keep in mind that the bin won’t make good compost all by itself. It’s up to you to compost the right materials in the right proportions and to keep it moist and aerated.

The key factors to consider when choosing a compost bin are:

  • Shop-bought or home made? Home made bins should beat least 1m x 1m x 1m to generate enough heat.
  • Will the bin be for kitchen waste, garden waste, or both?
  • How much do you want to spend and how easy do you need it to be?

Plastic Bins

Plastic bins

Plastic compost bins cost about 80€ and can be used for both kitchen waste and garden waste since they are rodent proof. They usually have a large lid which makes it easy to add new material and a door at the bottom lets you take out finished compost whilst the bin is still active. If you keep both the bottom door and the lid closed then the bin is rodent proof.

Tumbler Bins

Home-made tumbler bins

Tumbler bins can be used for both kitchen waste and garden waste since they are rodent proof. They are usually more expensive (and can cost from 100€ upwards) than plastic compost bins and are often smaller to enable them to be turned easily. On the other hand, they make aerating and watering the compost very easy. Further, if you can recycle suitable barrels from the waste tip then you can make them yourself for free – as the owner of the four tumbler bins in the adjoining photograph seems to have done.

Wire Mesh Bins

It doesn’t get cheaper or simpler than wire mesh

Wire mesh bins are simple and cost 10€ to 25€ to make. They can be as simple as a circle of mesh – as in the adjacent photograph – or a wire mesh cage. They are used primarily for garden waste since they are not rodent proof although it is possible to add a small proportion of kitchen waste if it is well buried.

Wooden Bins

Wooden bins – the ultimate in flexibility

Wooden compost bins can be bought from about 60€ upwards, but are easy to make if you have a little carpentry experience. They can be as large or as small and as cheap or as expensive if you wish. You can find numerous plans on the internet. Like wire mesh bins they are not rodent proof and so are primarily for garden waste.

The Three Bin System

Whilst a single bin is perfectly adequate to generate good quality compost quickly and easily, a “three bin” system is easier still.

The “Three Bin” system has three areas for (a) fresh, (b) recent and (c) old compost. This three bin system is made from wooden pallets. Simply join the side pallets to the back pallets by driving in two nails at 45-degree angles from the rear of the bin at both top and bottom corners. Illustration by McKibillo.

A three-bin compost system allows you to have different piles of compost in various stages. You start the pile at one end in the first bin; when the first bin is full, you “turn it” and move its contents to the second bin; when the second bin is full, you “turn it” and move its contents to the third bin; and when the third bin is full it should be fully rotted and ready for use in the garden.

A three bin system can be made with any bin type, but it is easiest with three adjacent wooden bins. As shown in the accompanying photograph, you can even build one for free if you can find seven pallets and some nails. They are particularly suitable if you’re generating large volumes of compost. Two people can build a three-bin compost system from this plan in an hour or two.