If you have a compost heap or bin in your garden, it’s likely using one of two methods: hot composting or cold composting.
Hot compost heaps and bins break down waste material so rapidly they generate steaming heat—sometimes even hot enough to cook in! This method is efficient, rewarding, and offers unique benefits. Despite what some might say, it’s not as difficult as it looks.
On the other hand, many gardeners prefer a more laid-back approach. With cold composting, materials break down naturally over time without generating significant heat. It’s slower, requires less effort, but still produces perfectly good compost.
Which method is best for your garden? That depends on your time, resources, and composting goals.
So in this guide, we’ll explore:
- Commonly asked questions about hot composting
- What hot and cold composting are
- A comparison of the two methods, including their pros and cons
- Which one is right for your garden
What is hot composting?
Hot composting occurs when composting conditions such as moisture, oxygen and temperature are optimal. These optimal conditions lead to an oxygen-loving bacteria which in turn generate heat.

Do note that you don’t want compost to be too hot, as it can destroy the diversity of bacteria in compost. One study by PF Strom suggests limiting the maximum compost temperature to 60 degrees for this reason.
Learn more: The Mind-Boggling Role of Bacteria In Compost | The Science of Compost: How Compost Happens
What is cold composting?

Cold composting breaks down organic material naturally over time, without generating significant heat. Since conditions don’t support such rapid bacterial growth, the process is slower and relies more on fungi and anaerobic (oxygen-free) bacteria as oxygen levels reduce.
Cold composting often occurs due to factors such as:
- Insufficient insulation.
- Oversized compost materials.
- An imbalance of greens (nitrogen-rich) and browns (carbon-rich).
- Excessive or insufficient moisture.
- Poor airflow.
While slower than hot composting, cold composting will still provide nutrient-rich compost for your garden – it just requires more time!
Hot and cold composting compared
♨️Hot Composting | ❄️Cold Composting | |
Speed | Can be ready in weeks (but you still need to leave it mature). | Can take a year or two. |
Materials | Some balance of browns and greens is required. | While a mixture of browns and greens can help, this is less important. |
Maintenance levels | Can be high, depending on the method used | Low |
Size required | If composting in the open, a large size is required. However, insulated bins can be used to compost smaller materials. | Any size |
Odour | Reduced odours. | More likely to smell. |
Pathogen elimination | Eliminates pathogens both in the hot and cooling stages. | Pathogen elimination takes place in the cooling down stage. |
Weed seeds | Killed if temperatures rise high enough for long enough | Weed seeds survive. |
Herbicides and pesticides | Some, but not all, are broken down in the hot stage | Fewer are broken down |
Moisture level | Can get too dry in the hot stage | Can get too wet |
Tools | It helps if you have a thermometer! | Only garden tools are needed. |
Distribution of finished compost | Finished compost is distributed throughout the heap/bin. | More likely to have unfinished materials in the outer areas of the compost heap. |
Hot v. cold composting Q&As

How does hot composting affect speed?
Hot composting bacteria breaks down much of the organic material super quickly. This can take many months off the composting process. Cold composting can easily take a year or more.
However, do bear in mind that the compost is not ready to be used after the heat has dissipated. Claims you see of compost being made in 18 days refer to the first part of the process – not the curing stage. See 5 Reasons to Mature Your Compost for Longer for more info.
Do you need to turn compost regularly to get it hot?
Not necessarily. Compost is turned in order to introduce air into the heap. There are other ways to introduce air, such as using bulking agents or pipes. Here’s 11 ways to aerate compost…
How does compost affect the materials you can compost?
You can compost a wider range of materials with a hot compost heap, including meat. (I’ve even composted dead chickens – when I turned the heap, the only thing I found were a couple of bones.)
In contrast, you have to take more care with cold composting, as the material won’t be broken down as quickly. Compost the wrong things and you run an increased risk of smells, pathogens and vermin. As we’ve seen, it also helps hot composting if you break down materials – this is not required with cold composting.
How does hot and cold composting affect odor?
Cold compost heaps can also give off more smells (which can be compounded by using the wrong materials or by an anaerobic composting process).
This is caused by increased emissions of VOCs (Volatile Organic Compounds) i.e. compounds that are emitted as gases.
Which is better for composting weed seeds?
Hot composting is better than cold composting for weed seed elimination. Weed seeds can survive for many years (sometimes even centuries!)
If you get your compost hot enough for long enough, you will kill more weed seeds, reducing the need for ongoing weeding after you have used the compost.
Do both hot and cold composting kill pathogens?
Hot composting kills a lot of pathogens quickly. However, it’s worth remembering that compost controls pathogens in a number of ways – and heat is only one of them.
For example, the beneficial microbes in compost compete for resources with pathogens. They release antibiotics that attack microbes, and they can penetrate and kill germs.
(See The Pathogen-Destroying Power of Compost for a deep dive into this fascinating area.)
Which is better for dealing with herbicides?
If you are using materials from outside your garden and kitchen, herbicides and pesticides can be a problem. Hot composting can really speed up the process of getting rid of some. However, even hot composting doesn’t get rid of all pesticides and herbicides.
Which is more difficult, hot or cold composting?
Hot composting can be more tricky than composting.
As we’ve seen, you don’t need to turn your compost every two days – but you do either need a larger pile or a compost bin, and to put some thought into its construction.
I also find moisture is one of the trickier things to get right with hot composting. The heat that is generated often means the initial moisture gets used up, especially in dry summers. It’s one of the reasons why I turn my compost heaps at least once, as I often find I need to spray layers of the compost to introduce more moisture.
This is much less of a problem with cold composting – which is instead likely to get too wet, increasing the chances of bad odours.
What tools do you need for hot and cold composting?
Other than the garden tools you already have in your shed, you don’t really need any tools for either method. That said, hot composting does become easier when you have composting tools such as a compost fork or a thermometer.
A thermometer lets you know if your compost heap is not hot enough – or indeed if it is too hot, and action is required. That’s something you don’t need to worry about with cold composting.
Learn more: Compost Tools Guide | Compost Thermometer Guide
Bringing it all altogether: Choosing the right method for you

If you have a decent-sized garden, or access to plenty of compost material, I’d suggest hot composting. With a little bit of investment of either time or money, you can generate high-quality compost in less time – and have fun doing so at the same time.
However, if you have a small garden, and are lacking in time or enthusiasm, cold composting might be the way forward. It may take longer, but you will end up with compost in the end – and it will still be full of nutrients and beneficial microbes.
For me, hot composting is my personal preference, partly because I just enjoy the challenge! But when life gets busy, I’m happy to let nature take its course with cold composting.
Whichever you choose, the most important thing is to compost. Ultimately, whatever method you use, you are turning a waste product into a resource which is incredibly valuable for your soil, your plants and your garden.
Ready to make compost? Learn the essentials with our guide: The Five Rules of Hot Composting.
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