Compost Magazine

Composting tips, advice and science.

Cartoon of a compost bin in a garden.

How to Use a Compost Bin (The Only Guide You’ll Ever Need)

I’m a massive fan of compost bins. 

They’re a simple way to turn waste into a rich compost that will benefit your garden for years to come. 

They also come in all shapes and sizes – and in my garden I’ve got everything from a homemade trash bin composter for generating heat to a three-bin pallet system for handling large amounts of garden waste. 

But if you want the most out of your compost bin, it’s essential to use it correctly. 

Just how, though, depends on the type of bin you are using.

Very broadly speaking, there are three different kinds to choose from: 

  • Bins that require airflow for composting. 
  • Bins that use worms to turn organic waste into worm castings. 
  • Bins that don’t need airflow. 

In this article, we’ll be focusing on the first type.

If you need more guidance on the types of bins you can use, check out our guides Which Compost Bin Is Right For You? and How Compost Bins Work.

How do compost bins work?

Infographic showing how compost bins work.

Compost bins work by keeping organic material in a compact structure and allowing microorganisms to break down that material into a brown crumbly material that you can add to garden soil or plants. 

Those microorganisms need moisture, air and warmth to work to maximum effect. 

Bins often have aeration built into them. Depending on the bin, these can be simple holes in the side or a system designed to draw the air up from the bottom to a vent at the top. 

The best bins have insulation built into them, which allows you to hot compost with less material than you would need with a closed bin.

See How Compost Bins Work for more information.

Composting in 6 simple steps

Chances are, you’ll be using a bin that uses air to make compost – also known as aerobic composting. If that’s the case, and you do the following and nothing else, you WILL get compost. 

  1. To start off: Ideally, put twigs and sticks, scrunched up cardboard or similar material at the bottom of the bin to create air spaces. 
  2. Materials: Add organic materials through the top of the bin. Make sure you include both green (high nitrogen) and brown (high carbon) materials. Try to ensure at least some composting materials are small in size. 
  3. Moisture: Add water if dry, add dry materials if wet. 
  4. Mixing: Stir in the top elements as you add more material. 
  5. Wait
  6. Finish: Remove the finished compost from the bottom of the bin, or fork out from the top if you are using an open bin.

However, a little bit of knowledge can get you better, faster compost, so let’s take a look at it in more detail. 

First, choose the right location

Sunsetting over a beautiful garden.

When choosing the perfect spot for your compost bin, there are a few things to keep in mind. 

First, make sure it’s a convenient location for adding materials and turning the compost. For example, if you have multiple vegetable beds, you might want to place it in the center. 

That minimizes your average journey time per wheelbarrow, reducing the overall effort you need to put in. 

On the other hand, If you’re mostly composting food scraps from the kitchen, make sure to place the bin in a location that’s not too far from the house, as it can be difficult to muster the enthusiasm to trek down to the garden in the winter.

However, you don’t want it too close, as any pests attracted may migrate to your house. 

Place the bin close to a water source so it’s easy to add moisture. If you get a dry compost bin, the last thing you want to do is be trudging back and forth with a watering can!

Finally, if your bin has an open bottom, avoid placing it near trees if you can, as their roots are likely to grow into the compost. 

It’s not always possible to get the perfect location, and sometimes you have to balance one against the other. But the more factors you can consider the better placed your bin will be.

Related: Siting A Compost Bin? Here’s What You Need To Know

Let your compost breathe: Maximizing airflow

The Darlac aerator deep in compost.
Above: This aerator is a handy tool for getting air into compost.

Air is essential for making compost in a typical bin.

You can help this process by: 

I. Adding items such as twigs and cardboard at the bottom of the bin. 

Ii. Adding bulking agents to the compost materials. This can include items such as sawdust or perlite

Iii. Stirring the bin. This also helps mix high carbon and high nitrogen material together. You may only be able to stir the top. 

Iv. Using a compost aerator. These devices can often reach deeper into the compost bin to help aerate the device. Examples include the Darlac Aerator (UK only) and the Ejwox Aerator (see video further down this post).

Related: 11 Ways to Aerate Your Compost (Only One Involves Turning!)

Choosing the right compost materials

Include both ‘Greens’ and ‘Browns’

The microorganisms that break down organic material need both carbon and nitrogen.  

You can provide these by including high nitrogen (Greens) and high carbon (Browns) materials.  

Confusingly, Greens and Browns refer to the carbon and nitrogen levels, not to the color!

For example, coffee is brown in color, but because it is high in nitrogen is called a ‘Green’ in composting parlance. 

Here are some examples of Greens and Browns:

Tea leaves
Kitchen scraps
Shredded paper

Note that weeds are usually mostly green. However, when you pull weeds, they often come with soil attached, which is high in carbon.

Because of this, you can often put in weeds without adding more brown materials. 

The ratio of greens to browns varies depending on the source, with some advocating for more browns and others recommending an even mix.

Personally, I aim for a 50-50 mix.

That’s partly because Greens contain a lot more water than Browns, so when you add what looks like the same amounts of both, you are actually adding more browns. But it’s also because I often have a lot of greens, and it can sometimes be challenging to source enough browns!

However, despite the fact that many guides prescribe very strict C:N ratios, studies show you can successfully compost with different ratios, and there’s certainly no harm in increasing the amount of browns you have.

It’s also well worth stockpiling Browns in the winter, when there tend to be more high carbon materials available. (I also used to buy a large bale of sawdust to use, but now tend to make a visit to the local sawmill, where a bottle of wine gets me as much sawdust and wood chippings as I can shovel into sacks!)


What to put (and not put) in your compost bin

Browns and greens in a compost bin, along with a compost stirrer and a thermometer.
Mixture of different compost materials in an insulated compost bin.

If you have a hot composting system, you can compost almost anything which has recently been alive. 

Hot composting kills most pathogens and weed seeds and rapidly decomposes materials that can attract pests. (Although you should still bury smelly items in your compost pile). 

However, if your compost is not hot, it is best to be a bit circumspect and limit what you add. 

By hot, I mean at least 50 degrees, and ideally higher. I’ve tried burying things at lower temperatures, only to find burrows in my compost the next day!

What’s more, if you do want to be ambitious and try more challenging compost materials like fish, I have found that adding an additional layer of sawdust can help reduce both smell and pests.

Here’s some examples of things that you can and can’t add to a compost heap. 

Okay for a cool compost heap: 

  • Most weeds (but avoid invasive weeds/weeds with seeds)
  • Leaves (shred if possible)
  • Sawdust
  • Shredded paper or newspaper
  • Wood ash (not more than 10%)
  • Biochar (can speed up composting process)
  • Fruit and vegetable scraps
  • Coffee grounds
  • Tea leaves (best emptied from tea bags because of microplastics)
  • Grass (make sure you mix it with a ‘Brown material)
  • Manure from herbivores
  • Urine
  • Pet and human hair
  • Alcohol

Best to avoid unless hot composting:

  • Meat and dairy products
  • Fish 
  • Bones
  • Grease, oil and fat
  • Ash from coal or briquettes
  • Pet droppings

Reduce size of materials

Bacteria are better at breaking down smaller pieces of organic material than bigger pieces. 

That’s because the surface area of the material increases when you break it up, allowing them greater access. 

Consider breaking up your material to about an inch to an inch and a half. You can chop, slice or grind your material to do this. 

You don’t have to do this with every piece of material you add, but the more you do the faster the composting process will be. But it’s a balance too between how much work you want to put in and how much you care about speed.

If you have large amounts of material, consider using a compost shredder. However, for the most part, a pair of gardening shears will do the job.

Layering or mixing the materials in the bin

Sawdust being layered on top of grass.
Here I am layering a ‘Brown’ (sawdust) on top of a ‘Green’ (grass).

Once you have selected your compost materials, and reduced their size if you need to, you need to combine them. 

Mixing them together is the best solution, and I sometimes add sawdust to the container on the back of my lawnmower before adding grass cuttings to the compost bin. 

However, if you have a lot of material this can be time-consuming. I generally run out of enthusiasm for mixing everything together after a few weeks in the spring!

Instead, you can choose to layer Browns and Greens. 

This is as easy as it sounds. Put down a layer of Greens, and cover it with a layer of Browns. 

Keep the layers thin if you can – an inch thick works well, but you can get away with two-inch layers too.

Ensuring moisture levels are correct

Graphic showing moisture requirements in a compost bin.

Getting moisture levels correct is also very important with closed compost bins. 

As already mentioned, with open compost bins and piles, the compost is turned. 

That allows you to check moisture levels. 

To do this, take the compost in your hand and squeeze. It should feel like a wrung-out sponge. 

If it’s too dry, add water. 

When it’s too wet, turning it will sometimes solve the problem. However, if that doesn’t work you can always add more dry, brown materials to soak up the water. 

However, it can be more challenging to ensure the correct moisture levels in closed compost bins, as you can’t easily see the compost in the middle of the bin until it’s ready to be harvested from the bottom of the bin.

That makes it more important to get it right when you add materials.

Ideally, you want to aim for about 45-60% moisture.

Bear in mind that kitchen scraps and grass cuttings tend to be very high in moisture, so it’s worth ensuring that at least some of the browns you add are dry. 

MaterialMoisture Content
Vegetables and fruits80-90%
Grass clippings80%
Shrub trimmings 15%

Source: Composting for a New Generation

Related: Moisture in Compost: Everything You Need to Know

How to know when your compost is ready to use

When the bin has finished the initial process of composting, the compost should be dark brown and crumbly and smell like soil.

However, freshly-made compost is not ready to use on tender plants, as it can contain high levels of salts and other substances that can harm plants.  

It’s best to leave it mature before using it, as the compost will stabilize over time. 

How long depends very much on what you are using it for. 

If you want to use the compost for seeds, pots or tender young plants, I’d suggest leaving it for at least 9 months.

If you want to put it on the veg beds in the autumn, when it will have all winter to be incorporated into the ground, you can get away with using it a lot sooner. 

Related: 5 Reasons to Let Your Compost Mature for Longer

Seasonal considerations

Compost bin with snow on top.


If you have an open bin, take steps to protect it from the rain. Covering it with a tarpaulin will work. Place branches under the tarpaulin to create air pockets. 

Harvest finished compost to spread on the veg and flower beds for the year ahead. 


As the cold hits, and you add less green material, the compost bin will likely slow down and need less or no turning. However, some composting will still take place. 

You can insulate your bin to retain heat, cover it to protect it from rain and stockpile brown materials for spring and summer. 


If you haven’t been doing it through the winter, now is a good time to aerate your compost after winter and start a new compost heap.

Check to make sure you have enough high-carbon material – a large bag of sawdust or woodchips can work wonders. 


As temperatures rise, your compost needs more attention and more aeration. If it is hot, consider providing shade. Keep an eye on moisture levels, adding water if needed. 

One common mistake to avoid

When you cut your grass, you often have a pile of fresh organic material to add to your bin. 

It’s tempting to just throw it in – and when it rapidly starts heating up, you think you’re a composting genius. 

Check back a few days later, though, and chances are all you’ll find is a soggy, compacted mess. 

To balance all the nitrogen and moisture in grass, mix it with plenty of browns such as sawdust, shredded paper or shredded leaves.

Troubleshooting common issues

Problem: Rodents are getting into the pile.
Solution: If your compost is hot, bury smellier items deeper into the compost. If you have a cold compost heap, avoid putting smelly items in the compost pile. Depending on your bin, you may also wish to block off openings with mesh. See our articles on Preventing Pests in the Compost Heap for more tips. 

Problem: Compost smells of ammonia.
Solution: Your pile has too much nitrogen. Add more brown material such as shredded paper or sawdust.

Problem: Compost smells like rotten eggs:
Solution: Your pile is probably too wet. Add dry materials like shredded paper or leaves. You can also aerate your compost, as this sometimes helps too. 

Related: 9 Easy Ways To Stop (Outdoor) Compost From Smelling

Problem: Slow decomposition
Solution:  If your compost is not decomposing as quickly as you would like, it may be due to a lack of nitrogen-rich material, a lack of air or a lack of moisture. To speed up decomposition, add more green materials like grass clippings, vegetable scraps or even urine, aerate your compost and ensure your compost stays moist but not too wet.

Problem: Overheating
Solutions: Sometimes, your compost bin may become too hot, which can kill off beneficial bacteria and slow down the decomposition process. Ironically, while aeration can help heat up a compost heap, it can also help to cool it down, at least in the short term. You can also consider adding more brown materials, adding some water and providing shade. 

Useful tools

Stirrer with red handle and stainless steel in a black compost bin.
A stirrer in my hot bin. This is a great tool for mixing old and new compost materials at the top of the compost bin.

You don’t need many tools, other than what you likely already have, but the following are very handy:

Aerator: This is a special tool that can reach deep into the compost and create air passages, enabling you to provide oxygen without having to turn the heap.

YouTube video player

Stirrer: A tool to mix new contents into the top of old contents is very handy. Mine came with my HotBin, and doesn’t seem to be available outside the UK, but anything that can mix the compost around will do.

Compost Thermometer: I’m also a big fan of compost thermometers. While not strictly essential, they a great learning tool, as you can see how different material combinations affect the heat of the compost.

Related: Compost Thermometer Guide | Composting Tools 

Getting more advanced

How to use a three-bin compost system

If you have a lot of material to compost, I’d recommend a three-bin compost system. 

Usually, each bin contains compost in a different stage. 

Bin 1: Fresh compost material, which will (hopefully) heat up before it is turned.
Bin 2. Compost material that is either hot or cooling.
Bin 3: Compost that is either maturing or ready for use. 

When you have used the compost in bin 3, you turn bin 2 into bin 3, bin 1 into bin 2, and refill bin 1.

However, I find that one turn is usually enough to ensure good compost, so this year I am experimenting with a modification to the system. 

You can read all about it in our full guide to the Three Bin Compost System, which includes tips on how to build and use the system.

Using a compost bin for heat

Trash can composter with thermometer, perforated PVC pipe and plants and seeds placed on top to keep them warm.
A DIY trash bin composter with a PVC pipe – this is an experimental set up!

Once you’ve got the hang of hot composting, you can use a bin to heat a greenhouse or a small polytunnel. 

Depending on the size of your bin and greenhouse, it won’t usually make the greenhouse or bin super hot, but it can help keep the temperature above freezing. 

You can also use the bin to provide warmth for tender young plants.

You can use an existing bin, or convert a dustbin. 

Here’s one way to do it:

  • Take a regular dustbin
  • Drill holes in the bottom
  • Place the bin on bricks to ensure airflow
  • Place a container under the holes to catch leachate
  • Fill the bin with a material such as fresh manure mixed with straw

You can also drill air holes in the side to maximize airflow, but this can allow leachate to spread everywhere. 

As I write this, I am an experimenting with using with alternative airflow method – using a PVC pipe with holes to funnel air through the middle of the bin.

The idea is that leachate goes through bottom holes into a container, with the air provided by the PVC pipe. If it properly gets up to heat I will report back 😉

No Dig Guru Charles Dowding uses an alternative to this system by using the heat from compost bins to germinate seedlings – see the video below for details. 

YouTube video player

Other bin types

So far we’ve covered how aerobic bins work. 

There are other types, so let’s briefly touch on them. 

Bokashi bins

These bins use anaerobic (without air) decomposition to ferment food into pre-compost. You add food scraps, add bokashi bran, expel as much air as you can, and let it ferment for two weeks.

See Bokashi Bins, A Complete Beginner’s Guide for more information. 


Digesters use anaerobic bacteria to decompose organic material. Their use is quite different, so we will cover these in more detail in a future process.

Worm bins

Worm bins are also quite different, as you are looking after live creatures and feeding them on a regular basis. Again, these require specialized information.

Electric composters

Filling the electric composter.

These devices are a type of kitchen bin that is powered by electricity. 

Some devices merely grind and dehydrate the devices, while others use actual bacteria to simulate the conditions in compost.

With the second type, the key is to start off slowly and build up the food you put in over time, as the bacteria need time to activate and breed before they can handle a lot of material.  

These bins do use electricity, so are best for people who want to compost but don’t have a garden. 

Learn more:
Are Electric Composters Worth It?
Reencle Electric Composter Review

Wrapping up

If that seems a lot, remember there are just 5 keys to using a compost bin. 

They are:

  • Air
  • Moisture
  • ‘Brown’ and ‘Greens’
  • Insulation
  • Reducing the size of the material

For an easy way to remember the five keys, see our infographic, The Five Rules of Hot Composting

Happy Composting!


Can I use my compost bin in the winter?

Absolutely! In fact, a closed compost bin offers advantages here over an open bin, as it offers some protections from the element.

It’s also worth noting that materials do tend to decompose in winter, although at a slower rate. The freezing and unfreezing process may even help with this by breaking down the cell walls of organic materials and releasing nutrients.

Can I add citrus peels to my compost bin?

While some people worry about adding citrus peel to bins, it’s not usually a problem as the quantities added are not enough to affect the pH of the bin. Even if you add large amounts, there are steps you can take to balance the pH.

See the Myth of Non-Compostable Items for details.

Can I compost biodegradable plastics?

So called biodegradable plastics are difficult to compost, and only break down in high temperatures.

They are probably best avoided unless you are an experienced composter who can achieve consistently high temperatures in your compost bin.

Read more

Home Composting: A Beginner’s Step-by-Step Guide to Getting Started
A Beginner’s Guide to Compost Bins: Which One Will Work Best for You?
How to Use Your Compost When You’ve Finished Making It

3 thoughts on “How to Use a Compost Bin (The Only Guide You’ll Ever Need)”

  1. Christopher Sedgley

    Thank you, the information is most beneficial even for a Master Composter.
    I’m very much interested in vermicomposting at the moment and have my composting worms living in a dedicated raised bed as well as a shop bought 4 tier wormery.
    I make most of my own compost and add some lime and sand to it , my vegetables do well.
    My question is if I add red wigglers to this organic matter in the raised beds and add mulch occasionally will they survive the growing season?

    1. Compo

      Hey Christopher, I’m not an expert in vermicomposting but I do know that some people use a trench composting method that includes composting worms, which sounds similar. Red wrigglers are not the best if exposed to freezing conditions (other earth worms like the European nightcrawler do better – see: but I’d have thought you’d be okay until winter. I have an interview with an expert on this coming up shortly so I’ll be sure to ask about this too.

      1. Compo

        hi Christopher, here’s a comment on your question from Heather of Wriggly Worms:

        “Worms can stand all sorts of different temperatures and so as long as there is food, air and moisture they generally keep going for years as they lay eggs and so the ecosystem of life and death continues.”

Leave a Comment

Your email address will not be published. Required fields are marked *