Horticulture Magazine

How To Make A Compost Heap In Your Garden Or Allotment

foodstuffs in compost heap

Do you want a simple, natural solution to improve the flowers or crops you’re growing?

Would you rather avoid using chemical fertilisers or pesticides on your garden or allotment?

If so, then composting could very well be the answer you’re looking for.

man using a spade to turn a compost pile

Composting is easy and efficient, and there are many benefits:

  • It helps you to do your bit for the environment by keeping food scraps out of landfill and reducing methane emissions.
  • It will enrich your soil, and give your plants the nutrients they need to thrive.
  • It keeps harmful chemical fertilisers out of ecosystems in your garden and beyond.

Sounds great, right? Let’s start by introducing compost, and the various types.

What is compost?

eggshells and greenery in compost bin
Composting can put your common household waste to good use

The word compost can refer to a pile where organic matter is left to decompose, and to the brown, soil-like substance you get as a result of the process.

It recycles nutrients in food scraps and other organic waste, meaning they can be put to use in your garden rather than thrown away.

Compost contains humus, which is the nutrient-rich material forming the organic part of soil.

(Not the stuff you put on your flatbreads: that’s houmous or hummus).

Depending on what type of compost you create it can take anywhere from weeks or months to be ready, but as long as you take care to do it right, you’ll have a usable product at the end.

When compost is dark brown, crumbly, and with a spongy texture, it’s ready to be used on your plants.

What are the benefits of composting?

broccoli plants growing from a fresh layer of compost in raised beds

Compost improves soil quality by delivering vital nutrients, retaining moisture, and suppressing weeds.

By using compost you get more vibrant flowers, fuller growth and plumper fruit and vegetables. What better way to get rid of your organic scraps!?

It also reduces the amount of food sent to landfill (and how bad your bins smell).

When food is sent to landfill, it is left to decompose anaerobically (more on this later), and produces methane as a result. [source]

The less food that is sent to landfill, the less methane is generated. [source]

So it really is a win-win. And it’s easy!

What are the different types of compost?

gloved hands sifting through compost heap

There are two main types of compost: aerobic and anaerobic. [source]

Aerobic composting refers to methods where compost is aerated, and the oxygen circulated through helps to fuel natural decomposition.

In anaerobic composting, there is no oxygen involved. You leave the scraps alone – usually buried – and let them get on with it. They will break down more slowly, and generate more smells thanks to the release of gases like methane. This is what happens to food sent to landfill.

Unless you plan to throw scraps in a container and forget about them completely for a year, most of the common methods for garden composting are aerobic.

Here are the main types.

Hot compost

temperature gauge showing 42 degrees celcius

By mixing air into your compost – a process called ‘aeration’ – you achieve conditions that let bacteria thrive.

They will break down your scraps at a high temperature, over 50°C, and give you a nutrient-rich compost in no time.

If you want compost quickly, this is the method for you. Hot composting can give you a usable end product in as little as four weeks.

Hot compost decomposes evenly, kills diseases, insects, and weeds thanks to the high temperatures, and doesn’t smell!

Cold compost pile

food scraps being pushed from a chopping board into a compost pile

This requires less effort than hot compost, but it may be over a year until you can use the compost in your garden.

To create cold compost, you just need to throw your scraps in a pile, either in a container or on the ground and wait.


bokashi composting with food scraps and inoculated bran

This is an anaerobic composting method that uses a special bran to help food break down more quickly and to reduce the smell.

Vermicomposting, or worm composting

hands holding compost with many visible worms

If your garden is too small for a compost pile, worm composting may be for you.

Simply feed your food scraps to your worms and let them break it down into compost for you.

We won’t cover this in the guide, but you can buy worm composting kits from places like Urban Worm.

How to get ready for composting

an outdoor contained space with waste vegetation

First you need to decide which type of composting you’re interested in.

Then you need to decide whether to use a pre-built container, to build one yourself, or to just set aside an area of your garden.

Whichever you choose, you’ll need at least a square meter of space.

Try to find a site that is in the shade: the bacteria and fungi that fuel the composting process work best in constant conditions, and shade is better for this than sunlight.

If you’re using a specialised container, you can keep it anywhere in your garden, probably somewhere out of the way.

Waist height compost bin
This is a great height for a composting bin

Waist height is about right for a container: you want to be able to reach in comfortably.

If the container has a plastic bottom, add a layer of soil before adding compostables. This  provides soil nutrients that would otherwise be accessed through the ground.

If you’re not using a container, make sure your compost pile is somewhere that puddles will not form after rain.

Too much water can disrupt the moisture levels of the pile – good drainage is important for this reason, too.

Ensuring optimum conditions will encourage worms to get involved in breaking down your compost pile.

How to establish a hot compost pile

For hot compost, you want about a meter squared of space: any bigger than that and it is hard to maintain the correct balance of nutrients and moisture.

You can use two bays next to each other for hot compost: when it comes to turning them, turn from one bay to the other.

two bay composting system in a large field

To start the pile, add about six inches of brown leaves, hay, or wood chip to the bottom of your bay.

Then three inches of green: Grass clippings, manure, coffee grounds, or fertiliser.

For optimum effects, hot compost needs roughly equal parts of green and brown matter

If you scroll down to the bottom of this guide you can find more detailed information about what counts for each.

After you’ve added your greens and browns, add a thin layer of dirt, and water each layer.

man turning compost heap with a spade

Leave this to sit for a while, then turn after two days. Turning involves mixing the pile into itself to give everything a chance to be near the hot centre.

You’ll need to aerate your pile frequently, and this can be done with specialised tools or with an old-fashioned pitchfork.

When you turn your hot compost, you’ll find it heats up surprisingly quickly. You’ll feel the heat emanating after just a couple of days as you turn the pile.

Keep a container in your kitchen for scraps, and add it to the compost pile when it’s full (or starting to smell!).

Storing this in the freezer reduces the smell: just chuck the frozen scraps on the compost pile and let them defrost. (Make sure this container is made from a material that doesn’t retain smells. Stainless steel is a good shout).

How to establish a cold compost pile

cold composting in the corner of a garden

Cold compost requires less effort than hot compost: just put your scraps in a pile, and leave them to it.

When you’re adding new scraps to your pile, try to bury them in the middle. This will contain smells and reduce the risk of attracting pests to your pile.

To speed things along you can aerate occasionally, although cold compost will work without it.

Be careful not to add weeds, because the temperatures reached by the pile will not be high enough to kill the seeds.

What can you put in your compost?

decaying contents of a compost pile, with vegetables and fruit visible

One of the great things about composting is how versatile it is. You can put pretty much anything in your compost pile, with a few important exceptions.

Here are the things that can go in all compost piles:

  • Vegetable peels and scraps
  • Fruit skins and scraps
  • Plant prunings and flower cuttings
  • The ends of carrots, parsnips, spring onions, and so on
  • The stalks of peppers and any other stalky vegetable
  • Tea bags and paper coffee filters
  • Grass cuttings
  • Leaves
  • Egg shells
  • Hair
  • Used matches
  • Tooth picks

Non-organic matter like egg boxes and balls of paper can be added, too.

These decompose more slowly, but add carbon to the mix, as well as pockets of air which are useful for gently aerating cold compost.

Egg shells are a great source of minerals in compost. If you bake the shells before adding them to your compost pile they will crush up better, and any salmonella that may of been present will be killed.

When adding fallen leaves, not that adding too many can disrupt the balance of your pile.

If you’re making hot compost you can add weeds and diseased plants to your pile as well.

The temperatures reached in the pile are high enough to kill the weed seeds and plant pathogens, meaning that weeds or disease won’t affect your pile.

What to leave out of your compost

an illustration highlighting which foods and produce can and cannot be composted

For compost to work properly, certain things must be left out.

This will also help reduce pests and prevent bad smells (proper aerobic compost should not smell bad at all).

Here’s what to avoid:

  • Meat
  • Fish
  • Oil
  • Dairy
  • Anything that has been treated with herbicide
  • Any human or animal waste (except horse manure)
  • Glass or plastic!

If you’re using a Bokashi system, you can add meat, fish, and dairy, but you should take extra care to avoid adding liquids.

How to stop pests getting to your compost

Is a fear of rats holding you back from composting?

If so, it doesn’t have to. By following a few simple tips you can keep your compost completely pest free!

Pests are attracted by strong smells, so most of these tips revolve around reducing the alluring scents.

Mouse on top of compost pile
Bury large food scraps to keep these guys away

Leave out meat, dairy, grease, and bones. We mentioned these above in the “what to leave out of your compost section”, but it can’t hurt to reiterate.

These are the ingredients whose smells are most likely to attract rodents and other pests.

Aerating your compost often will speed up the decomposition of larger, more enticing food scraps.

Pests don’t like their food sources to be disturbed either, so if it is mixed up regularly they will look elsewhere.

Bury greens under browns. Keeping the mixture correct will make the compost smell less strong.

Moistening your pile can help, too. It should be about the same wetness as a squeezed sponge: damp, but not saturated.

Composting rules of thumb

gloved hands showing wood chips in a plastic bag

If it’s too dry, add greens.

If it’s too wet, add browns.

Greens are things like fruit, and veg, which are quite moist. These ingredients contain nitrogen.

And browns are things like wood shavings and newspaper: Dryer, and more bulky.

There you have it…

a compost heap in a large garden wooden box

Composting is a fantastic way to reuse the food scraps you generate in your kitchen, and also to put grass clippings, fallen leaves, and similar to use.

The compost you create will strengthen plants and crops in your garden or allotment, and will help to improve the nutrient balance of your soil.

There are two types of composting, aerobic and anaerobic. Oxygen is involved in aerobic composting, and this method keeps bad smells to a minimum.

Most of the home-composting methods are aerobic.

You can easily set up a compost pile in your garden. Hot composting will give you compost in just a few weeks, whereas cold composting will take a bit longer.

Both can take all sorts of food scraps, and both will give you a nutrient-rich compost to use in your garden.

Composting is simple to set up and easy to maintain, and we highly recommend it for any gardener.

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