In this guide we’ll take a look at the best compost thermometers for your heap.
I’ve compared accuracy, lens quality, build quality and cost
to give you my top recommendations.
What Is The Best Compost Thermometer?
More Detailed Compost Thermometer Reviews
This compost thermometer features a clear and easy to read dial that measures temperatures of between 40 – 180 Fahrenheit, in 2-degree increments and also has measurements in Celsius (4-80 °C) The dial is colour coded, helping you see at a glance whether your heap is warm, active or hot. It also has a PC coated lens and is hermetically sealed to prevent condensation forming in the unit. To ensure many years of use, it has a water resistance rating of IP55.
The probe is 50 cm (20 inches) long and this allows you to get deep into the pile to measure the temperature at the hottest parts. The thermometer features a welded bolt between the dial and stem to keep the dial securely attached to the probe. The product is made from high quality 304 grade rust-resistant stainless steel.
I used this thermometer in a plastic compost bin and found it sturdy and well made. The thermometer was left in the pile over the course of a very damp week and I had no problems with condensation. This tool helped me to understand that my pile was too cold, and I was able to increase the heat by adding water and turning the pile at the correct times. Within a few days, the compost had already begun to warm up significantly.
The probe comes with clear instructions which explain the temperature zones and offer a great introduction to the technicalities of hot composting. It also includes a five-year warranty.
This is a durable thermometer that does the job really well. The excellent instructions also provide all the information you need to start hot composting.
This thermometer is well made with a stainless-steel body and a 40 cm long probe. The 50mm dial is clear and easy to read. I did find that when left in the heap, the dial misted up a little with condensation and became difficult to read. However, the measure does react quickly to changes in temperature, so you could just insert this product when you needed to check the temperature and keep it in a dry place when not in use. The measurements are in Celsius only.
Overall this is an accurate and easy to use thermometer, just don’t leave it in the rain or in your compost heap for long periods.
This stainless steel thermometer has a 50mm dial and a 50 cm probe allowing you to read it easily and test the temperature deep within the pile.
The dial is clear and easy to read and has a colour coded scale that measures from 0 – 100°C and also indicates when the pile is warm, active or hot. The measurements are shown in Celsius only. The probe and dial are securely attached and well made. I left the unit in my compost bin over a week and found no problems with condensation.
This is a great value thermometer that works well, doesn’t mist up and is clear and easy to read.
Compost Thermometer Buying Guide
There are several key factors to take into consideration when choosing a compost thermometer
Firstly, check that the dial is clear and easy to read and that the measurements are in the unit you prefer.
Secondly, ensure that the unit is made from strong rust proof material such as stainless steel and that the dial is sealed to prevent water from seeping in. The best thermometers have an IP55 rating which guarantees against moisture getting into to the dial.
Bear in mind that the longer the probe, the closer to the centre of the heap you will be taking measurements from. Your measurements don’t need to be right at the centre but taking measurements close to the surface will not give accurate results.
How do you use a compost thermometer?
Simply insert the thermometer into the pile as far as it will go. Wait until the hand on the dial stops moving and make a note of the temperature. It is advisable to check the reading in several areas of the compost heap as there is not always a uniform temperature across the pile and you may occasionally find cold or hot spots.
How often should I turn my compost and what temperature should my compost be at when I turn it?
Ideally, you should turn your compost after each burst of heat. When the temperature of your pile reaches 130-140°F (55-63°C) this is the ideal time to turn. You should then leave it until the temperature rises again, which usually takes between 5 and 7 days.
How do I know when my compost is ready for use?
To ensure that all diseases and weeds are killed you should monitor your compost pile carefully to ensure it has reached a temperature or between 140 – 150 °F (60 – 65°C) for three to four days. It is then safe to use. However, your compost will benefit from being left for a few days to cure and cool down before use. Do not allow your heap to remain at temperatures above 150°F (65°C) for more than a few hours as this could cause beneficial microbes to begin to die off.