Composting

The UK’s Best Compost Thermometers For Measuring Compost Temperatures

thermometer placed in compost
Written by Chris Briggs

Hot composting is a great way to ensure the plants in your garden get an ideal source of nutrients. Compost thermometers are a great help when creating hot compost piles – allowing you to easily measure the temperature.

In order to make use of hot composting, you’ll need to ensure the right temperature is maintained. The best way to do this is by using a compost thermometer.

A compost thermometer will allow you to see the temperature of your compost pile at any time. Knowing the temperature of your compost pile is vital since it enables you to make the necessary adjustments so you can achieve the ideal temperature.  

Things to consider when buying a compost thermometer are –

  • The length of the probe
  • How easy it is to read
  • The quality of materials used
  • The time it takes to get a reading

We’ve rated some of the UK’s best compost thermometers. We’ve looked at all their key features and have covered their cons as well as pros, so you can make the right decision when purchasing one.

Last update on 2020-10-19 / Affiliate links / Images / Pricing from Amazon Product Advertising API

Let’s start by looking at our best pick, the Thermometer World 295mm Temperature Probe…

Best Pick: Thermometer World 295mm Temperature Probe

High quality and robust thermometer

The Thermometer World 295mm Temperature Probe is our best pick and is a high-quality and easy-to-use thermometer.

The probe is 295mm long, and while that isn’t particularly long, it’s suitable for small to medium compost piles. The 50mm dial diameter also makes it very easy to read. It’s made from stainless steel, so it’s very robust and suitable for use in all weather conditions.

There are markings on the dial that shows when your compost is at risk of becoming too hot or too cold. This is very useful when you’re working with hot compost and want to ensure it stays at the right temperature. The dial shows the temperature in Celsius as well as Fahrenheit and it only takes a few moments to get a reading.

To get an accurate reading, it’s important that the probe is placed in the centre of the compost pile.

Overall, this is an excellent thermometer and will give you an accurate reading so you can keep your compost piles at an optimal temperature.

Pros

  • Markings on the dial allow you to easily maintain the right temperature
  • The 50mm dial diameter is very easy to read
  • Shows temperature in both Celsius and Fahrenheit  

Cons

  • There are cheaper thermometers available
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Value Pick: Haia 7k4k Soil Thermometer

A good quality thermometer at a great price

The Haia 7k4k Soil Thermometer is our value pick and if you’re looking for a thermometer that’s simple, easy-to-use and low cost, then this would make a great choice.

It has a 50mm wide dial, which is very easy to read, with the temperature shown in Celsius – starting at 0 and going up to 120°C. The probe is 500mm long, which makes it ideal for use on large compost piles.

It’s constructed very sturdily from premium stainless steel and the fact that it’s hermetically sealed helps to avoid issues with condensation – always handy when you’re working with hot compost. Once you’ve inserted the probe into the pile, you get a reading within roughly 30 seconds.

Unfortunately, it doesn’t have markings to indicate when your compost is going above or below the optimal temperature but if you’re aware of the temperature range to aim for, this isn’t too big of a deal.

Overall, this is a very reliable thermometer that’s excellent for use with medium to large compost piles and for the price, it’s hard to go wrong.

Pros

  • Very affordably priced
  • The 500mm probe length makes it great for those who have large compost piles
  • Gives an accurate reading within 30 seconds
  • Sturdily constructed from stainless steel
  • Hermetically sealed to avoid issues with condensation and moisture

Cons

  • Some reviewers did have issues with the condition it arrived in
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Reotemp Backyard Compost Thermometer

Reliable and easy-to-use

The Reotemp Backyard Compost Thermometer is reliable and robust and because it’s hermetically sealed, you don’t have to worry about it fogging up.

The probe is 20 inches in length (just over 500mm), so you could certainly use this thermometer on larger compost piles. The 1/4 inch dial is easy to read and gives you the temperature in Celsius, going up to 100°C. There are also markings on the dial to let you know when the temperature is steady, active and hot.

Another nice feature of this thermometer is that it comes with composting instructions included. Even if you are experienced creating your own compost, it’s still a nice addition.

Like most compost thermometers – it’s very simple to use. You just need to insert the probe into the centre of the pile, and you’ll get a reading within 30 seconds or so.

This would make a great choice for most domestic gardeners and the markings make it easier to ensure your compost piles don’t go above or below the correct temperature.

Pros

  • The 20-inch probe means it’s ideal for use on larger compost piles
  • The dial is easy to read and has useful markings for keeping compost within the ideal temperature range
  • Comes with composting instructions included
  • Is constructed very sturdily and is hermetically sealed to avoid the dial fogging up

Cons

  • Is quite expensive
  • Doesn’t come with free delivery
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ETI Ltd Stainless Steel Thermometer

A robust and reliable thermometer

The ETI Ltd Stainless Steel Thermometer is another product well worth considering if you’re looking to create your own hot compost.

Just like the Reotemp thermometer – there are markings that show when the compost temperature is warm, active and hot and the fact that it’s colour-coded makes it very easy to read. The temperature reading is in Celsius and goes up to 100°C.

The probe is 500mm in length, which makes it very versatile for use with compost piles of different sizes. The 50mm hermetically sealed dial is resistant to fogging, so you’re able to use it in all types of weather conditions.

This is reasonably priced for a thermometer of its type and it comes with free delivery, so it’s certainly worth considering.

Pros

  • Stainless steel construction means it’s very robust
  • Colour markings on the dial make it easy to keep your compost piles at the ideal temperature
  • The 500mm probe makes it suitable for use with compost piles of many sizes
  • The 50mm dial is easy to read and resistant to fogging

Cons

  • Some reviewers had issues with getting an accurate reading
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Green Wash Ltd Compost Thermometer

Bare-bones but gets the job done

Lastly, is the Green Wash Ltd Compost Thermometer. This is quite basic compared to the other thermometers we’ve looked at, with just a simple grey dial that doesn’t have any markings for creating hot compost.

The dial gives readings in Celsius and it’s quite clear and easy to use, providing you’re aware of the right temperature range to aim for when creating hot compost.

The body is made from stainless steel, so it’s very robust. The probe is 400mm in length, so it isn’t as long as a lot of the other thermometers we’ve looked at. This isn’t necessarily an issue though, especially if you’re working with smaller compost piles.

It comes with a product manual included, although it’s very simple to use so you’re not likely to need it.


Unfortunately, condensation can be an issue with this thermometer. Several reviewers had issues with the dial fogging up and making it difficult to read.

Pros

  • Sturdily constructed from stainless steel
  • 400mm probe length is big enough for most small-to-medium compost piles
  • The dial is clear and easy to read
  • Instruction manual included

Cons

  • Very basic compared to a lot of other thermometers, with no colour markings on the dial
  • Condensation getting into the dial can be an issue
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What Is The Ideal Temperature For A Hot Compost Pile?

The ideal temperature for a hot compost pile is between 55 and 60 degrees C (130-140 degrees Fahrenheit).

Although hot composting is beneficial for many reasons (more below), a compost pile can get too hot and if it does it can cause the beneficial microbes to be killed off. A compost thermometer will enable you to avoid this problem.

The Pros and Cons of Hot Composting

Hot composting has some key benefits over cold composting. These include –

Versatility

With a hot compost pile, you’re able to use more types of food waste. A lot of food waste isn’t suitable for cold compost because it will cause issues with odour and likely attract unwanted pests, such as flies, rats and mice to your garden.

With a hot compost pile, you don’t have this concern, which means you are able to make use of most, if not all, the waste from your food bin.

Safer to work with

Hot compost is safer to work with for a couple of reasons. Firstly, it will kill unwanted pathogens and bacteria, which can be a real issue with cold compost. Hot compost will also kill fly eggs and larvae, so it’s much safer to work with overall.

Reduced space requirements

The fact that you can create hot compost piles relatively quickly also helps to reduce space requirements. Cold compost piles can take a long time to create by comparison and so you’ll need more space, particularly if you’re creating multiple piles.

Some of the cons of using hot compost are –

Difficulty and effort required

Creating a hot compost pile can be quite challenging, particularly if you’re new to it. Getting the right temperature is an art, and although having a compost thermometer certainly helps, you still need to know the right materials to use in order to get the best results.

Can be a fire hazard

Hot compost piles catching fire isn’t especially common, but that doesn’t mean there’s no risk of it. The best way to avoid this risk is to keep an eye on the temperature of your pile and make sure it doesn’t go above the level you require. A lot of thermometers will have markings to help with this.

Things to Look For When Buying a Compost Thermometer

Buying a compost thermometer isn’t as big an investment as a lot of other types of gardening equipment and generally, most thermometers work in a very similar way. That being said – you still want to make sure you get a good quality thermometer that you can rely on. With this in mind – below are some of the key things to consider when buying one –

Length of the probe

The length of the probe can vary quite a lot with compost thermometers. The length of the probe is something you need to consider since you want to make sure it goes deep enough into your compost pile to give you an accurate reading.

Most thermometers on the market will have a probe long enough for small to medium compost piles, but if you’re working with a very large pile, then you might need a thermometer with a longer probe.

Quality of materials

Since you’re going to be using a compost thermometer outdoors, you want to be sure that it’s sturdily built and will not break or crack easily. Most good thermometers are made from stainless steel, which means they’re plenty strong and will hold up well in harsh weather conditions.

How to Use a Compost Thermometer

Using a compost thermometer is very simple. Be sure that you get a thermometer with a probe long enough for the size of your pile. Then simply insert the probe into the centre of the pile and wait for around 30 seconds to a minute to get an accurate reading.

In order to ensure your compost pile reaches the optimal temperature, you’ll need to ensure you have the right mixture of nitrogen and carbon materials as well as making sure it gets enough heat from the sun.

About the author

Chris Briggs

Chris loves the outdoors and exploring nature. He is a freelance writer and has written extensively on subjects including travel, DIY and gardening.

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