8 Best Worm Composting Thermometers (Review)

For earthlings, optimum temperature plays a pivotal role in our lives. The same goes for the tiny little worms, who are working day and night to give you a fertile compost. So, to keep your little wormies healthy, active and make them live happily in their settlements, temperature plays a pivotal role in addition to other factors. Worms are efficient in warmer temperatures. The best temperature prescribed to take the optimum results from your worms is 80 to 160 °F (27-70 °C). See our temperature guide if you want to learn more.

Your worm needs special attention in winter when the environmental temperature falls beyond 10 degrees Celsius. When the temperature falls down 5 more degrees, your worms will go into hibernation.  In temperate zones, farmers create artificially controlled environments to get maximum results.  If you want to know more about how to survive worm composting in winter, see composting in wintertime. However, if you are new to vermicomposting and looking for worm kits for your backyard, we have curated a list of some of the best kits available online for your backyard,  see our worm farm kit review.

Worm Composting thermometer is the must-have tool for every worm composting farmer. It helps you to keep a check on how your worms are feeling in their home.

Why Temperature is important for Worm Composting?

For worm composting, not only worms are required, but we need other microorganisms, like mesophilic, thermophilic bacteria, actinobacteria, protozoa, rotifers, fungi, and so on to boost up the process. Now all these microbes and worms enjoy working at a certain temperature and if the temperature is not maintained, all these processes will stop working and that will result in slow or no efficiency. To keep a check on the health and efficiency of our red worms maintained temperature is very important.

Therefore, temperatures within compost piles heavily influence microbial activities, growth, and reproduction, and hence the production of raw material. Higher temperatures are good for composting. However, extreme temperatures that are greater than 160˚F can thwart microbial activity.

In this perspective, the temperature has key importance, and to monitor, a thermometer is an essential tool for gardeners and farmers involved in worm composting and many other fields related to agricultural science. However, if you want to know about Don’ts, see our information about things to avoid when you start worm composting

How does a worm composting thermometer work?

Worm Composting thermometer generically consists of a probe with a dial interface on one end and a sensor on the other. In the market, the probe length varies between 7.5” to 48”.
For better evaluation of temperature place it at 3 to 5 different areas in the center of the pile and take the average. By doing so, you’ll be able to get a mean range of temperature that will help you make a decision on what further actions are needed.

Why do I need a compost thermometer?

In order for organic materials to decompose, the best temperature to maintain is 80 to 160 °F. If it gets cooler, the decomposition process slows down, and unwanted parasites and bugs may accumulate. On the other side if it goes any hotter, and your compost pile may impact beneficial microbes responsible to digest the material.
A temperature range of 80 to 160 °F) is the perfect environment for worms and composting-friendly microbes to flourish, which ultimately turns your pile into rich and fertile compost.

A compost thermometer helps us know exactly what temperature our pile is maintaining, and what further steps we should take for better results.

What to do for a cold compost below 80 °F?

After placing a thermometer if you see the temperature of your pile is getting down way below 80 °F, try to aerate, loosen or turn the soil with a long stick or a pitchfork. In this way, microbes within the pile will breathe oxygen. So, getting the air flowing inside your pile will help them reproduce. When they’ll start breathing and reproducing, the pile temperature will start rising up automatically. Moreover, if your compost is dry, add some water and if too wet, add more brown materials to neutralize.

Place a covering over the pile that will trap heat inside. We can also place mulch on top, which will act as a blanket.

Living in a cold area is a little challenging during winter. Make sure your pile gets enough sun to keep the process active.

What to do for a hot compost getting above 160 °F?

Temperature above 160 °F is also not good for your worms. If after placing your worm compost thermometer, you find out the temperature is higher than 160° F, the foremost thing is to add water to cool it down. Or if you have any covering on the pile, take it off immediately. Moreover, in summer try to provide shade over the pile to keep the pile safe from direct sunlight, which can raise the temperature of the pile to a much higher level. Another method is if you have a large pile, divide it into smaller patches.

How to Calibrate a Composting Thermometer?

Analog worm composting thermometers are usually accurate, but sometimes we come across a point where we need to re-calibrate our thermometers because a lot of time has passed, dropped, or getting exposed to high temperatures or otherwise.

For such conditions and security, every company provides a knob or screw at the back of the dial of the composting thermometer. So here is the generic way of how to calibrate your composting thermometer.

Arrange a reference bath of water of a  known temperature, which normally an ice bath. Add ice into a bucket, which is at least 6” in depth. Add water and stir. Fill only enough water that can only fill the gaps. Agitate bath before and during calibration.

Now, if the bucket is 6”, put your composting thermometer at 4”, and if 4” then place it at 3”. The thermometer should be plunged enough so that the sensor or sensitive portion of the thermometer is in the center of the bucket.

To calibrate, place your composting thermometer in the bath for at least a minute or a minute and a half, to make sure that the temperature has stabilized on your thermometer. At this point rotate the screw or knob to set the pointer to 32 °F (0° C). Generically, we need an L-key, pliers, or screwdriver to rotate this.

After adjusting it, put back any covering if available, and congratulations! You have successfully re-calibrated your composting thermometer again!

Note some worm composting thermometers may not provide this option, which may be because they are selling their product at a cheaper price and doing so for cost-cutting.

Best Worm Composting Thermometers

Let’s dig in and review some of the best worm composting thermometers available!

Backyard Compost Thermometer by REOTEMP

REOTEMP’s Backyard Compost Thermometer is the best thermometer is the perfect match when you are looking for a thermometer for your backyard worm composting. It comes with many sizes of probes, out of which 16” and 20” are the highest selling thermometers.  It has the best readability and accuracy features.

The dial is 2” in size, is completely sealed, accurate, durable, and inscribed with a range of temperature where when set, your worms will feel active and work proficiently. Three zones marked on this thermometer as ‘steady’, ‘active’, and ‘hot’, which give you immediate visual ease.  This is amazingly effective as it allows you to instantly acknowledge the stage of your compost, rather than remembering the temperature that correlates to a certain zone.

REOTEMP’s backyard compost thermometer is sealed and airtight which makes it among the toughest candidates for worm composting thermometers that can stay overnight in your backyard.

You can also choose the scale of your thermometer before purchasing whether Fahrenheit or Celsius. The separate version is designed on purpose as they want to keep it simple while reading values on the scale and not to let you get confused. So before buying make sure which version you prefer.

The packaging used by the REOTEMP thermometer is environment friendly and can be used as a composting material after shredding. If you are new to worm composting, on buying this version you’ll get a free PDF guide to let you know all the basics and important factors involved in worm composting.

Backyard Compost thermometer seizes the guesswork out of composting. It gives you understanding and indications that what you want to do with the pile, that is when it is time to turn your pile when to add more ingredients when is the time to water and when composting is complete.

REOTEMP’s backyard thermometer is one of the perfect companions for your compost pile, bin, or tumbler.

Cate’s Garden Premium Stainless Steel Bi-metal Thermometer

If you are looking for a thermometer in a reliable budget and of high quality, Cate’s Garden compost thermometer is the best compost thermometer for you. It has been carefully designed to make it convenient to use and accurate temperature readings for your compost pile. The thermometer is made up of stainless steel, with a hermetically sealed lens to prevent fogging. Moreover, it has a 20” long probe to get deep into the pile and obtain an accurate reading. The stem has a diameter of 3/16”.

Cate’s Garden compost thermometer interface is divided into 3 temperature zones; warm, active, and hot.  Its dial displays both Celsius and Fahrenheit scales in a smart way with the main dial in Fahrenheit. Furthermore, a guide for composting, temperature zones, and Celsius conversion, are printed on the back of the package.

Here are some of the basic features of Cate’s Garden compost thermometer:

• The thermometer is very sensitive to changing temperature and immediately tells you the ongoing temperature of the pile in seconds.
• The result is surprisingly accurate.
• The long probe helps find the temperature of the core of big piles quite conveniently.
• The compost thermometer’s stem is sturdy and durable.
• The dial of Cate’s garden premium stainless steel thermometer has a very smart and easy-to-read dial. Color zones help you understand where easily the condition of your pile. Also, the color zones won’t cause any hindrance to reading temperature either on Fahrenheit or Celsius scale.

Smart Choice Stainless steel soil Thermometer

If you are looking for the most durable, high temperature-responsive, and cost-effective thermometer for your backyard pile, Smart Choice’s Soil thermometer is the thermometer for you.

The thermometer has a dial of diameter 1.5” with a temperature measuring capability between 0 and 220 °F. The stem is 5” long and sturdy.

It is perfect for reading worm compost temperature but can also be used in other places like measuring the soil temperature of plants and so on. This thermometer is used by many professional gardeners to manage ideal composting and recommended by them. This is because of the reasonable size of the stem as well as durability and responsiveness.

The dial is designed to get as accurate readings as possible which are pretty helpful while determining microbial activities within your composting. This thermometer makes composting trouble-free and more productive by accurately measuring the temperature.

Moisture in front of the dial always creates frustration for the farmer as many times a lot of humidity is involved in composting, which many times results in fogged dials or clogged needles. Smart Choice’s thermometer is sealed to prevent moisture to enter that ultimately prevents it from clogging or fogging due to moisture.

Urban Worm Soil Thermometer

Urban Worms Soil Thermometer is another one of the most in-demand thermometers in the market. This composting thermometer has green, yellow, and red marks for easy monitoring of the optimum temperature for your backyard worms.

The length of its probe is 5” and is perfect to use for your small composting areas. The temperature calculator range is low, but it is the best thermometer for those who are worm composting in their backyards or indoor.

Not only piles, but you can also use this composting thermometer to measure the temperature of most of the plants.

It weighs around 1.13 ounces and comes in the packaging of 5.74×2.04×2.
If you are looking for a cost-effective, long-lasting, and water-proof worm composting thermometer this is the exact thermometer you are looking for.

General Tools Soil and Composting Thermometer

General Tools Long-Stem Soil Thermometer faultlessly calculates the temperature of pile or soil from 0 to 220 °F.

The general thermometer has a 20” long probe which puts it in the list of composting thermometers used for heavy-duty jobs. The probe is rust-proof and made up of durable stainless steel.

The 2” dial is designed in an extremely simple way and can measure temperatures at a wider range. So if you want to pursue worm composting and want to keep your budget low but still do not want to compromise on quality, then this is the exact composting thermometer for you.

This thermometer is not only suitable for composting, but you can use it to measure the temperature of your soil in your garden and other agricultural methodologies. It comes in the packaging of 2” x 2” x 20.5” and weighs around 3.99 ounces.

KT Thermo Worm Soil Thermometer

KT THERMO’s Worm composting thermometer is the cheapest thermometer in the category of some of the best worm composting thermometers.  It has a dial of 2” with a long probe of 8”.  The dial is colorfully designed to let you know how your little works are feeling inside the pile.

This thermometer is perfect to use with Worm farm starter kits, worm factory, Vermihut, or any other red worm composting kit available in the market.

So if you want a thermometer that would be in budget and durable too, then KT THERMO’s Worm composting thermometer is important. Color-coded dial helps us take action immediately when we see the temperatures in dangerous ranges.

The thermometer weighs around 2.89 ounces, and it comes in a package of dimensions 8.78” x 3.11” x 3.03”.

REOTEMP Heavy Duty Compost Thermometer

REOTEMP heavy-duty compost thermometer is one of the highest quality products available online that can be used for temperature sensing. It has a probe of 48”  and suitable to check the temperature accurately in deep piles at bigger farms. Its stem is 5/16” thick and is hermetically sealed. It has a bigger dial compared to all we have discussed earlier. The dial is 3” and is very easy to read. The temperature ranges from O °F to 200 °F which never fogs up.

This model is also compatible with the REOTEMP FM-0 probe for extra protection of the dial.

It comes in two variants one with Fahrenheit and the other with Celsius scale. This model also comes with one year of limited warranty.

The thermometer is professionally graded and design for larger compost piles. It is also water-resistant and sensitive to changing temperatures. Therefore, responds actively to changing temperatures.

A gauge is present at the back of the thermometer if you need to calibrate it. Moreover, it is designed for heavy-duty operations, so it won’t get rusty or foggy even if it is placed open overnight in a humid environment.

There are three variants of probes available for REOTEMP Heavy Duty Compost 24”, 36”, and 48”.  REOTEMP Heavy Duty Composting thermometer is one of the best professional-grade thermometers for compost at a larger scale.

Heavy Duty Digital Compost Thermometer by REOTEMP

Digital thermometers are never considered reliable by people around the world and for that, we agree as well. However, this digital thermometer is different. Heavy Duty Digital Compost Thermometer by REOTEMP is designed very professionally and is very accurate. They have invested a lot in the thermal sensor to make it as accurate as possible and regulated it with an intelligently designed integrated circuit.

It operates at very low voltages. Thus, its battery has a survival time duration of 5 years.

It is NEMA 4X and IP67 compliant, meaning water-resistant against jet pressures and fully dust resistant. It has high accuracy with a standard deviation of ±0.95 °F or ±0.53 °C.

The probe is also heavy with a thickness of 5/16”. The dial has protection around in orange. The orange color helps find the thermometer easily if placed somewhere in big compost piles.

REOTEMP Heavy Duty Digital Compost Thermometer comes with a limited warranty of one year and is a bit heavy. It weighs around 9.93 pounds and its packaging has a dimension of 57 x 8 x 8 inches.

Heavy Duty Digital Compost Thermometer can calculate a greater range of temperature. It has two probe variants 36” and 48”. This worm compost thermometer is used by people related to vermicompost at the commercial level.  This is made in the USA and has good market penetration. REOTEMP digital compost thermometer is a quality for money.

Wrapping Up!

Choosing the right thermometer for your worm compost is really important and most importantly it should display the accurate temperature as well. That is why we have curated the most authentic thermometers that will never be going to disappoint you.

When buying a product everyone has their own point of view for selection of products. Having said that, we have tried our best to give an option to every one of us looking for the best worm compost thermometer with respect to value, quality, design, readability, weight, durability, and so on.

So, We hope you liked the information we have shared.  Also, the foremost thing is having a thermometer that can monitor the temperature of the pile. Now, having said that no matter which product you will choose you are definitely going to love it. If you have any inquiry related to red worm composting or looking for any special topic that you are looking to answer for feel free to contact us by clicking here. We will get back to you as soon as possible. Cheers!

See our temperature guide for worm composting here: Temperature Guide for Red Worms and for colder seasons: How to Keep Red Worms Safe in Winter.