My first compost thermometer came with my HotBin and proved to be a lot of fun.
For the first time, I was able to accurately measure temperature – and realize that sometimes my compost was hot enough to cook in!
But for me, the real value of a compost thermometer is as a learning tool. There’s a lot that goes into getting compost to the perfect temperature – the right amount of water, oxygen, greens, browns, and how often you turn.
By measuring the temperature frequently, you start to gain an idea of what works well and what doesn’t.
And it doesn’t matter how many guides you read – the only way to get really good at it is to experiment in your garden and your climate with the materials you have at hand. Until you have a thermometer at hand, though, you never fully know the impact of any changes you make.
A good compost thermometer can also help let you know when the best time to take action is.
For example, this summer I was testing using a compost aerator to keep compost oxygenated after turning it. When the temperature of the compost dropped right down after two weeks, I knew it was time to stop aerating the compost and leave it mature.
Previously, we’ve looked at how to choose and use a compost thermometer. In this post, we’ll cover some of the best options available.
At a glance
|Brand||Features||What’s special||Buy On Amazon|
|Reotemp 16 Inch Backyard Compost Thermometer||16-inch stem|
|REOTEMP technology and quality at a reasonable price||USA | UK|
|Reotemp Heavy Duty Compost Thermometer||Rugged 36-inch stem|
Accurate readings Can be recalibrated
|Extremely robust, best for professionals and enthusiasts||USA | UK|
|Rukars Long Stem Thermometer||20-inch stem|
|Longer stem than most entry-level thermometers||USA|
|VeeGee Dial Compost Thermometer,||12-inch stem||Best option for insulated compost bin||US|
|Thermometer world||Color-coded dial||Budget option||USA | UK|
Reotemp 16 inch backyard compost thermometer: Best overall
First the brand. You’ll notice this is not the only compost thermometer from Reotemp featured here, and there’s a reason for that.
Reotemp has been manufacturing compost thermometers for nearly 60 years, is a soil builder member of the US Composting Council, and really knows what they are doing when it comes to thermometers.
The 16 Inch Backyard Compost Thermometer comes with a 16-inch length stem, which makes it ideal for composters with medium size compost piles. However, is too long for my HotBin, where the composting action takes place closer to the surface.
It may not be quite as long as the next one mentioned, but it does make up for that with a much cheaper price!
The thermometer comes with a very easy-to-read dial, with temperature ranges split into Steady, Active, and Hot, all color-coded so less experienced composters can see at a glance what range their compost heap falls into. The colors could be a little more distinct, though, and can be hard to read in dim conditions.
Like the Reotemp Heavy Duty Compost Thermometer, this compost thermometer is hermetically sealed to ensure it doesn’t fog up, and is made from stainless steel to ensure it is long-lasting. The ¼ inch diameter of the stem doesn’t quite match up to the heavy-duty version but will be fine for the average amateur composter.
One final nice touch – the thermometer comes in compostable packaging which can be added as a brown to your compost. It doesn’t add much in volume, but it’s nice to see the impact on the environment has been minimized.
One tip – don’t make the same mistake I did and throw the packaging away! Depending on the model you get, you may find a QR code on the thermometer which takes you to a composting guide.
- Easy-to-read compost dial
- Free digital compost guide
- Hermetically sealed to prevent fogging
- Some versions only display temperature in one format (celsius or Fahrenheit)
Reotemp heavy duty compost thermometer – (36 inch stem): Best overall
If you have a large compost pile, need seriously accurate readings, and a compost thermometer that is built to withstand the elements, it’s hard to do much better than the Reotemp Heavy Duty Compost Thermometer.
As the name suggests, this one, in particular, is a robust thermometer that is hermetically sealed to prevent moisture from gathering inside – meaning it is always clear and easy to read.
It’s also robustly constructed from stainless steel – in the USA too – which means it can both withstand the worst the weather can throw at it and last for years. The thermometer can be calibrated – but out of the box, there’s little need for that, as it comes with pinpoint accuracy.
The Reotemp Heavy Duty Compost Thermometer comes with a 36-inch stem, which makes it ideal for measuring the internal temperature of even larger compost heaps. The rugged 5/16″ inch stem means that this study device can be inserted into rough material without any fear of it snapping.
Unlike some of their other models, the dial is not color-coded, as this model is aimed at expert composters who don’t need the extra guidance.
One drawback is that while the Reotemp Heavy Duty Compost Thermometer can be used with a probe handle this is unfortunately not included. That’s a shame, as it is already an expensive device. There’s also the price, which will rule it out for the average home composter.
- Long, sturdy stem
- Robust construction
- Accurate readings
- Can be recalibrated
- Large, easy-to-read dial
- Probe handle not included
Rukars: Long stem thermometer at a reasonable price
Most composters will want to get a good reading on a decent size compost heap – but not everyone needs the 36 inches provided by the REOTEMP 36-inch compost thermometer.
The Rukars compost thermometer is a well-regarded device that comes with a 20-inch probe, which is sufficient for the average backyard composter, and all at a reasonable price.
Like the Reotemp thermometers, the thermometer is hermetically sealed to prevent a build-up of moisture. It also comes with three color zones to indicate whether a heap is steady, active, or hot, which makes it a great option for people new to composting. As with some other options here, it only shows Fahrenheit.
- Long stem
- Good value
- Only shows Fahrenheit
Buy on Amazon: USA
VeeGee Dial Thermometer: Best shorter stem option
Not every compost thermometer needs to be long. If you are using an insulated compost bin, and periodically adding compost material, you will find that the bacterial action which generates heat is taking place at the top of the bin.
Unfortunately, the options are more limited when it comes to shorter compost thermometers, and there are not many I can recommend. However, the VeeGee Dial Compost Thermometer is a good option at 12 inches, although some bin composters might find even this a little bit too long.
Do note that it doesn’t come with color coding, making it easier for novice composters to see the heat rating.
- The shorter length makes it more suitable for use with compost bins
- No color coding option.
- Not currently available in the UK
Buy on Amazon: US
Budget Buy: Thermometer World compost thermometer
Not everyone has got a fortune to spend on a thermometer, and if you’re not that serious about getting exact temperatures this is a fun first one to buy.
It’ll let you know if your temperature is getting hot or cold, and it comes with a handy color code that lets you know if your compost is warm, ideal or hot. It’s fairly (but not pinpoint) accurate, but if you leave it in your compost all the time it will fog up over time.
The construction is fair-to-middling – fine for dipping in the compost when you check it, but not suitable for leaving outdoors permanently. Do note that it has quite a short shaft, so it won’t suit a serious composter with a large pile.
That might all sound a bit negative, but it is exceedingly good value, and this would make an ideal first thermometer for someone dipping their toes into the fun world of composting.
- Budget option
- Handy color coding
- Great for experimentation
- Not very accurate
- Fogs up if left outside
- Could be more robust
My top choice for a compost thermometer, and the one I am currently using, is the Reotemp 16-inch thermometer. However, that doesn’t mean it’s the right one for your needs!
Key things to think about are how big your compost heap or bin is (and where it is most likely to be hot), do you want a color guide and whether you want Celsius, Fahrenheit – or both!
Compost Thermometer Guide
Hot v. Cold Composting