So, you want to make compost?
And I’m guessing you are trying to choose between a compost heap and a bin?
While I do have my own preferences, the system you choose really does depend on a number of factors.
To help you choose which is the right one for you, we’ll walk you through a number of different considerations (and also point you toward other composting options!)
First, though, let’s quickly define what we mean by compost bin (as this is a very broad term!) and a compost heap.
What is a compost bin?
A compost bin is a structure that holds the content of the compost together.
Composting bins come in many different forms. They can be constructed at home from pallets, bins, straw bales, and wire – in fact, the only limit is the materials you have available and your imagination!
You can also buy compost bins in many different sizes and shapes.
These include wooden bins that can be slotted together, plastic bins that provide a simple and cheap way to compost, and insulated bins designed for hot, fast composting.
Different types of bins can be used for different types of composting.
These include bins that use worms to break down material, and Bokashi bins that use effective microorganisms to pre-compost material.
Related article: Learn more about the different types of compost bins, and how to choose the one that will suit your needs best.
What is a compost pile or heap?
A compost pile is just what the name describes – a mass of compostable materials heaped into a pile.
Compost piles have been used for thousands of years.
In fact, it’s thought that in Neotlithic times these consisted of middens. These early Stone Age farmers are thought to have run their plows through the middens and then onto their fields.
Sometimes a compost pile is created all in one go – usually when speed is the priority – and other times it is added to slowly over time.
Twelve factors to consider when choosing between a compost bin and a compost pile
I’ve found that one of the key benefits of using a compost bin over and above a pile is structure.
When you have a compost heap, it tends to spread everywhere.
That’s the same whether you have a large heap or a small heap!
That may depend on you, to some extent, and how neatly you can construct it!
I’ve constructed several smaller heaps for experimental purposes, and they have never worked well for me.
However, I do have quite bad hand-eye coordination (even diagnosed with dyspraxia as a child!), and struggle with creating a neat, tidy pile, so that could be down to me!
One problem the lack of structure does cause is uneven decomposition.
With a bin, compost materials are kept together, and decomposition is more even.
With a pile, some parts will decompose more slowly because they are not insulated.
However, to some extent, this can be solved with regular turning.
How much material do you have to compost?
If you have seriously large amounts of material to compost, a pile is probably your best bet.
Do bear in mind, though, that you don’t want your pile to get too big.
As the pile increases in size, it becomes harder for air to move through it, causing anaerobic (without air) decomposition to take place.
In turn, that slows down the speed of decomposition, and can lead to bad odors.
According to Cornell University, the ideal heap size is 1-3 metres high (if not using powered aeration systems).
Piles with materials that decompose rapidly, such as grass, should be towards the lower end of the spectrum. If you have materials that break down slowly, you may need a larger heap.
My experience seems to bear this out, as I’ve seen very large piles that never seem to decompose correctly.
For example, there’s a farm near me that dumps all their manure in a huge pile. (It’s big enough to drive a tractor on top of it!)
Some of the manure has been sitting there for years.
But when I go to collect manure from the heap, I find that while the top is well decomposed, when I dig a spade or two deep, it’s not very well decomposed at all.
One other thing to bear in mind when choosing is to remember that compost shrinks.
While it is not that hard to fill even a reasonably sized pallet bin, you can keep on adding to the bin as the material shrinks.
If you have a multi-bin system, that means you can handle quite a lot of material!
If you do have a large amount to compost (for example, if you are on a farm), you might want to consider windrows.
A windrow is a long, narrow pile of compost often used for large-scale composting.
This method is often used for large-scale composting, such as on farms or in municipal facilities.
One of the main advantages of windrows is that they allow for better aeration than large compost heaps. This speeds up the decomposition process and reduces odors.
How much space do you have?
Compost bins come in many different sizes, and you can easily fit a compact bin in a tight corner. That means they are a great option if you are short of space.
However, compost heaps don’t have to be large.
What’s more, if you have a small garden, unless you are obtaining organic material from outside your house and garden, you won’t need a large pile.
As compost heaps tend to spread out, they do tend to take up more garden space than a compost bin, so bins do still edge out ahead here.
How much time and effort do you want to put in?
A compost heap is typically turned in order to aerate.
Turning also allows you to put the less decomposed parts from the outer layers into the middle, and vice versa.
These systems can require a lot of work!
Some systems recommend turning the pile every 2-3 days, although I think that’s a bit excessive unless speed is really important for you.
(It’s also the case that if speed is not important, and you don’t mind some anaerobic decomposition, you don’t need to turn the pile at all.)
In contrast, not all bin systems need turning.
A three-bin system will require two turns (or one in my revised system,) but some compost bins which use passive aeration do not require any turning at all.
Many bins are used as continuous composters.
You simply put material in at the top, and take it out at the bottom when finished – meaning you always have material in different stages of composting in the bin.
How concerned are you about pests?
If pest control is important to you, you are best off using a compost bin.
Because of their contained size, it is easier to block off access to pests with bins.
A large sprawling compost heap can be a lot harder to control!
See our guides to controlling rats and mice in compost for suggestions.
Insulation is key to maintaining a hot pile or bin, which results in faster composting.
With a compost heap, the outer layers provide insulation for the inner layers. However, a compost bin may or may not provide insulation.
Some bins don’t have insulation, while others, such as the HotBin, come with insulation built in.
These bins allow you to achieve hot composting conditions without using a large size.
Some open bin systems, such as palette bins, are large enough to allow you to add straw to the sides and top, which also helps traps warmth.
Another option is to use straw bale bins, which offer excellent insulation.
However, you can also insulate a compost pile by covering it with straw and a tarpaulin.
How much do you want to spend?
Bins can cost anything from very little (especially if you make your own bins) to hundreds of dollars or pounds for a deluxe version.
(I’ve even made one for free using an old, unused bin and some leftover PVC piping.)
If you had a lot to compost, and needed several large bins, the cost could mount up.
On the other hand, a compost heap is usually free to make.
(The exception is if you have very large amounts of organic material, and need to use machinery to move and turn the compost.)
How fast do you want the compost?
Both compost bins and piles can take a long time, or a short time, to complete the first stages of composting!
Compost bins can produce compost quickly if they are insulated and you follow the five rules of hot composting.
If the conditions are right and you turn a compost pile regularly, it will also produce compost quickly.
For example, the Berkeley method makes compost in just three weeks.
The main difference is that the compost heap will take more effort to make compost fast.
However, you should leave the compost to mature before use with both systems.
You might be wondering about smells, but the truth is both bins and heaps can produce smells if they are not treated correctly.
I mostly included this point because I have seen other guides say compost heaps smell, and compost bins don’t, which is not strictly correct.
I’m not going to go into this in too much detail, as we have a whole guide on how to minimize smells when composting.
However, it’s worth mentioning that one way to reduce smells is by using a layer of material like straw, sawdust, or compost as a biofilter to trap smells.
This is usually easier with a bin, as the compact design makes it easier to cover the top of the bin, and to line the bin with straw.
Beyond that, I think it’s a draw between compost heaps and bins!
Moisture is key to effective composting – but too much water can force air out of air pockets, causing anaerobic decomposition.
Due to wind and sun, open piles can dry out more quickly.
At the same time, unless a compost heap is covered over, it can become sodden and wet when it rains.
Closed bins help retain moisture, while their lids keep out excess rain.
It’s also easier to control moisture in an open bin, as the structure keeps an even surface which is easier to cover than a pile.
In theory, a compost pile should have more air flowing through it than a closed compost bin.
It’s exposed on all sides to air, which should help maintain oxygen levels for small to medium piles.
In practice, I’ve never found aeration to be an issue with a well-designed compost bin.
These bins often have air vents at the top and the bottom to encourage air to flow through the material.
How much do visuals matter to you?
Compost bins come in many different shapes and materials. You can get them made from wood or from plastic, you can construct your own pallet or wire bin, or buy a pretty beehive design.
In short, you have a lot of options to choose from, and at the same time the compost material is hidden away from the eye.
A pile is messy.
What’s more, as I mentioned earlier, it can be harder to pest-proof them, so you are more likely to see rodents running around your garden.
Bringing it all together
|Compost Bin||Compost Pile|
|Structure||Great for maintaining the structure||Looser, harder-to-maintain structure, can mean uneven decomposition|
|Size||Good for small to medium amounts. (A three or multi-bin system can still handle quite a lot of compost, especially as compost material can shrink rapidly.)||Best for larger amounts of compost – but consider windrows too.|
|Space||Compact options make these a great option for small gardens.||May take up more space than a compost bin, but these don’t always have to be large.|
|Effort||Depends on your system, but many bins do not require turning.||Usually require turning, which can be hard work.|
|Pest control||Easier with small bins.||More difficult to control pests.|
|Insulation||Some bins come with insulation, helping to maintain heat and increase composting speed.||Insulation can also be achieved using other methods, such as covering the compost with straw and a tarpaulin.|
|Cost||Varies from cheap to expensive.||Usually free to construct.|
|Speed||Depends on both the materials and the design of the bin.||Depends on both materials and how much effort you put into the heap.|
|Moisture retention||Closed bins allow easier control of moisture levels.||Open piles are exposed to wind, sun, and rain, making it hard to control moisture levels.|
|Air||Closed bins may have less exposure to air, but in practice, this is not an issue with well-designed bins.||Compost piles are exposed to air on all sides.|
|Visuals||Compost bins come in many choices and are the best option when visuals are important.||Often messy and unattractive.|
What does the research say?
There’s very little research on this topic, but I did find one study which looked at different ways to compost at home.
The study looked at composting with the following:
- Plastic bins
- Wood bins
- Rotary drums
- Ground piles
I’m assuming here that ground piles mean compost piles!
The study found that plastic compost bins and compost piles performed best in terms of maintaining temperature.
The systems were similar in terms of other factors, except for rotary drums, which proved to be the driest. The study suggested this could be because of poor aeration.
Don’t forget, there are many ways to compost…
You may have guessed that I prefer bins!
However, depending on your needs, both bins or piles can be a great way to make compost, so I hope this article helps you choose the best option for your needs.
But there are other ways to make compost too.
For example, you can use pit composting, trench composting or the cut-and-drop method.
To explore the different (and sometimes weird and wonderful!) ways you can compost, check out our guide to different composting methods!
Can I use a compost bin and a compost pile together?
Yes, and this can be very useful at times!
You can use a compost bin for year-round composting, and construct a pile in the summer when you have a large amount of waste.
You might also use a compost pile for large amounts of organic waste such as wood chips, and use a pest-proof bin for items that might attract rodents.
Is it easier to turn a compost bin or pile?
It is usually easier to turn a compost pile.
Open bins often require you to lift the material over the top of the enclosure, while closed bins need to be emptied out first.
However, bear in mind some closed bins are designed for no-turn composting. It also depends on the design of the bin.
For example, if you have wooden bins with removable sides, it can be easy to turn the contents from one bin into another.
A guide to using compost bins
How compost bins work
Adhikari, Trémier, Martinez and Barrington (2012) Home composting of organic waste – part 1: effect of home composter design International Journal of Environmental Technology and Management