Home Composting

Home Composting

Making and using compost is the cornerstone of gardening, especially organic gardening . The finished product is rich, dark, crumbly and sweet-smelling. It is made of recycled garden and kitchen waste, and can also include paper products. It is used to feed and condition the soil and in making potting mixes. Around 40 per cent of the average dustbin contents are suitable for home-composting so it helps cut down on landfill too. Making compost is often considered to be complex but all you need to do is provide the right ingredients and let nature do the rest – however, a little know-how will help you make better compost, more efficiently.

Where can I make my compost?

There are a variety of bins on the market but they are all just a container for the composting process. A bin is not strictly necessary – you can just build a heap and cover it over with some polythene or cardboard. However, bins do look neater and are easier to manage. You can build your own (see Homemade Compost Bins), buy one in from any number of suppliers, including The Organic Gardening Catalogue (see Buying a Compost Bin), or get one cheaply from your local council – contact the Waste and Recycling Department at your local council for more information or visit the recycle now website: www.recyclenow.com/home_composting

What can I compost?

Anything that was once living will compost, but some items are best avoided. Meat, dairy and cooked food can attract vermin and should not be home-composted.

Some things, like grass mowings and soft young weeds, rot quickly. They work as 'activators' or 'hotter rotters', 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 learnt by experience, but a rough guide is to use equal amounts by volume of greens and browns (see below).

Compost ingredients

'Greens'(nitrogen-rich ingredients)

  • Grass cuttings
  • Young weeds
  • Nettles (not roots)
  • Comfrey leaves
  • Urine (ideally diluted 20:1)
  • Uncooked fruit and vegetable peelings
  • Tea bags and leaves, coffee grounds
  • Soft green prunings
  • Animal manure from herbivores eg cows and horses
  • Poultry manure

'Browns' (carbon-rich ingredients - slow to rot)

  • Cardboard eg cereal packets, toilet roll tubes and egg boxes
  • Waste paper and junk mail, including shredded confidential waste
  • Newspaper & magazines - although in general it's better to send them for recycling
  • Bedding (hay, straw, shredded paper, wood shavings) from vegetarian pets eg rabbits and guinea pigs
  • Tough hedge clippings
  • Woody prunings
  • Old bedding plants
  • Bracken
  • Sawdust
  • Wood shavings
  • Straw
  • Autumn leaves (use them to make leafmould if quantities are large)

Other compostable items

  • Wood ash, in moderation
  • Hair, nail clippings
  • Egg shells
  • Natural fibres, eg wool or cotton

Do NOT compost

  • Meat
  • Fish
  • Cooked food
  • Coal & coke ash
  • Cat litter
  • Dog faeces
  • Disposable nappies

How do I make my compost?

You can make compost simply by adding compostable items to a compost heap when you feel like it. It will all rot eventually but may take a long time, may not produce a very pleasant end product, and could smell.

With a little extra attention - taking the 'COOL HEAP' route outlined here - you could improve things dramatically.

If you want to produce more compost in a short time, and are able to put more effort into it, follow the 'HOT HEAP' route.

The Cool heap route

  1. Collect together a batch of compost materials. Try, if possible, to get enough to make a layer of at least 30cm or more in the compost bin. Weed the garden, mow the lawn, empty the kitchen bucket!

    Aim for a mix of soft and tough items. It may help if you place a few woody plant stems or small twigs on the bottom first, especially if using a plastic bin, as this will improve the air circulation and drainage.

    Go to Step 2, or call by Hot Step 2 if you have time.

  2. Start filling the bin. Spread the ingredients out to the edges and firm down gently. Alternate soft and tough items, or mix them together first. Unless items are already wet, water well every 30-60cm.

  3. Continue to fill the container. Items can be added individually, but a bigger batch is preferable. If most of what you compost is kitchen waste, mix it with egg boxes, kitchen paper, loo roll middles and similar paper products to create a better balance.

    Go to Step 4, or take a detour via Hot Step 4 on the way if you feel like turning it

  4. When the container is full - which it may never be as the contents will sink as it composts - or when you decide to, stop adding any more. Then either just leave it to finish composting or go to Step 5.

  5. Remove the container, or everything from the container. If the lower layers have composted, use this on the garden. Mix everything else together well; add water if it is dry, or dry material if it is soggy. Replace in the bin and leave to mature.

The Hot heap route

  1. Gather enough material to fill your compost container at one go. Bring in manure, scraps from the market, neighbours' weeds and so on to make up the bulk. Make sure you have a mixture of soft and tough materials.

  2. Chop up tough items using shears, a sharp spade (lay items out on soil or grass to avoid jarring) or a shredder.

  3. Mix ingredients together as much as possible before adding to the container. In particular, mix items, such as grass mowings, that tend to settle and exclude air, with more open items that tend to dry out. Fill the container as above, watering as you go.

  4. Within a few days, the heap is likely to get hot to the touch. When it begins to cool down, or a week or two later, turn the heap. Remove everything from the container or lift the container off and mix it all up, trying to get the outside to the inside. Add water if it is dry, or dry material if it is soggy. Replace in the bin.
  5. The heap may well heat up again; the new supply of air you have mixed in allows the fast acting aerobic microbes, ie those that need oxygen, to continue with their work. Step 4 can be repeated several more times if you have the energy, but the heating will be less and less. When it no longer heats up again, leave it undisturbed to finish composting.

When is it ready?

Compost can be made in six to eight weeks, or it can take a year or more. In general, the more effort you put in, the quicker you will get compost.

When the ingredients you have put in your container have turned into a dark brown, earthy smelling material, the composting process is complete. It is then best left for a month or two to 'mature' before it is used. Don't worry if you compost is not fine and crumbly. Even if it is lumpy, sticky or stringy, with bits of twig and eggshell still obvious, it is quite usable.

Compost hints & tips

Autumn leaves

Store some dry leaves to mix with grass mowings and other soft green stuff. Make large quantities into leafmould - stuff wet leaves into black plastic sacks (loosely tied), or a wire mesh container. Use after a year or two. Mow leaves on a lawn to chop and collect them up.

Grass mowings

Mix well with tougher items to avoid a slimy mess. Leave on the lawn whenever possible - they will soon disappear and feed the grass; this will not cause 'thatch'. Can also be mixed into a leafmould heap, or used as a soil mulch.

Diseased plants

Persistent diseases, such as white rot and clubroot, are best avoided. A hot heap, turned several times, should deal with everything else.

Diseases that don't need living plants to survive - grey mould, mildews, wilts - may survive in a slow, cool heap. But heat is not the only factor that will kill diseases - the intense microbial activity will also help to dispose of them.

Perennial weeds

Some perennial weeds will be killed in a hot heap; avoid really persistent horrors such as celandine, bulbous buttercup, ground elder and bindweed. Don't burn or dump these weeds - they are rich in plant foods. Mix with grass mowings in a plastic sack. Tie it up and leave for a few months until the weeds are no longer recognisable, then add to the compost heap.

Weed seeds

Weed seeds may survive a cool heap, but should be killed in a hot one. If your compost tends to grow weeds, dig it in rather than spreading it on the soil surface.

Hedge clippings and prunings

Chop or shred tough prunings and clippings from evergreen hedges before adding to a mixed compost heap. Compost large quantities separately; even unshredded they will rot eventually. Mix with grass or other activating material; water well. Tread down the heap, then cover. In anything from a few months to years you will have a coarse mulch which can be used on perennial beds.

Animal manures

Strawy horse and cattle manure composts well. Keep a sack on hand to bulk up other ingredients. Manure mixed with wood shavings should be left to rot until the shavings are no longer visible. If it is dry, water well and mix with grass mowings, poultry manure or other activating material. When rotted use as a surface mulch. Wood shavings incorporated into the soil can lock up soil nitrogen, making it unavailable for plants for a year or more.

Small pets, like hamsters, don't produce many droppings but you can still use their waste as a strawy addition to the compost heap. Guinea pigs are marvellous - they love eating weeds and convert them quickly to prime compost material!

Paper products

Newspaper can be added to a compost heap, but in any quantity it should go for recycling into more paper. Cardboard, paper towels and other paper items can be scrumpled up and composted. They are particularly useful where kitchen scraps make up a high proportion of the compost ingredients. Avoid glossy paper and colour print.

Sawdust and wood shavings

Very slow to decay. Add in small quantities; balance with quick-to-rot activating materials. See also 'Animal manures' above. Do not use if treated with wood preservatives.

Composting questions answered

What is garden compost?

Compost looks like rich, dark soil. It is made of recycled kitchen and garden waste. It is used to feed and condition the soil and in making potting mixes.

Is it the same as multipurpose compost?

No. Sowing, potting and multipurpose composts that you buy in garden centres are mixtures of various materials such as sand, coir and fertilisers. These are used for raising seedlings and growing plants in pots.

Do I have to be an expert to make compost?

No. Composting just happens - it is nature's way of keeping our planet clean. Just follow the few basic rules in this guide.

Is it a lot of work?

Making compost can be as easy as putting a few weeds and vegetable scraps onto a compost heap - or you can put a lot of effort into it. It's up to you.

How long does it take?

Compost can be made in six to eight weeks, or it can take a year or more. In general, the more effort you put in, the quicker you will get compost.

Will a compost heap breed pests?

Compost is made by a host of small and microscopic creatures. These are not pests and will not overrun your garden.

Do I need any special equipment?

A garden fork is the only essential item. A compost bin keeps everything neater but it is not essential.

Will a compost heap attract rats?

Rats may visit a compost heap if they are already present in the area.

Is compost safe to handle?

Yes, if the usual garden hygiene rules are followed. Keep cuts covered, wash hands before eating and keep your anti-tetanus protection up to date.

Does a compost heap have to get hot?

No. A medium-sized compost heap can heat up to 70°C in a few days. The heat helps to make quicker compost, and to kill weeds and diseases. But your compost may never heat up, especially if it is made over a long period. The compost can be just as good, but it will take longer to be ready for use.

Does compost spread weeds and diseases?

Some weed seeds and plant diseases will survive in a slow, cool compost heap - if you add them in the first place.

Do I need a shredder to make compost?

No. A shredder can be very useful where there is a lot of woody material to be composted, but it is not essential.