Hygrometers are invaluable for keeping the temperature and humidity of your garden at an optimal level. These tools can tell you if you need to tweak the air conditioner or look for possible leaks in the venting system.
The right hygrometers should be fast in providing you an accurate reading of your garden. To help get you started, we picked nine of the best hygrometers in the market.
At A Glance: Our Top 3 Hygrometers
ERAY Digital Hygrometer – This unit can give you accurate readings on your grow room’s climate. Apart from just saving the readings within the unit, you have the option of sending the data to your PC. This helps you save time from typing all of the saved info onto a spreadsheet.
Amprobe THWD-3 Hygrometer – Another unit that has a very accurate sensor is the hygrometer from Amprobe. The unit features a long and small probe that can fit into most small openings. This helps you check on the temperature of your ductwork to find any leaks and fix them.
Mengshen Hygrometer – The Mengshen Hygrometer has a compact and lightweight design. You can easily place this in your pocket and is light to your grasp. The ergonomic design allows you to use the device with your thumbs. In addition, this hygrometer can measure the ambient, dew point, and wet bulb temperature of your grow room.
Reviews of the Best Hygrometers
The VLIKE Hygrometer can get an accurate temperature measure that ranges from -20℃ to 60℃. You can also switch the temperature setting to display Fahrenheit, which ranges from -4°F to 140°F.
It will also have a humidity range from 0 to 100% RH. Both temperature and humidity readings are on the screen at the same time. It uses an SHT11 digital sensor to get its measurements, which is less accurate reading than other versions of the sensor. On the other hand, this allows the unit to get a fast reading rate of 400ms.
In addition, the hygrometer can measure three different temperatures: dew point, ambient, and wet bulb. The ambient and wet bulb temperature ranges from -20°C to 60°C (-4°F to 140°F) with an accuracy of ±1.0°C (0°C to 45°C). The dew-point reading ranges from -50°C to 60°C (-58°F to 140°F). In addition, the tool has a min/max measurement for a better look at the readings.
This hygrometer can store up to 99 sets of data, which you can use to track any changes in the atmosphere of your garden. In addition, the unit has a backlight to help you read the screen.
- Multiple temperature readings
- Records up to 99 groups of data
- Dual display of temperature and humidity readings
- LCD screen backlight
The TES 1160 not only measures the temperature and humidity of the room, but also the atmospheric pressure, which ranges from 300 to 1200hPa. Room temperature reading ranges around -40℃ to + 100℃ (-40℉ to +212℉) while the humidity readings provide a measure of 0% to 100%R.H. All three measures are on the screen the same time to give you a clear picture of the state of your garden’s environment.
Apart from the normal temperature reading, this hygrometer can also check on the dew point and wet bulb temperature. These readings help you check on the garden’s water vapor pressure and water saturation pressure.
Another thing we like about the TES hygrometer is its durability. This unit can take a beating and still give you a good temperature reading in your garden for more than two years.
The hygrometer can save 99 sets of measured data. This helps you do comparisons to certain dates when you need to. In addition, the TES 1160 runs on a 12V battery that you can easily replace when it runs out of juice.
- Temperature, humidity, and water vapor pressure reading
- High durability and lifespan
- The hygrometer can save 99 sets of data
- The triple reading display on the LCD screen
- No backlight
The RockyMars RT36 Hygrometer is a mini portable temperature and humidity-measuring device. Its temperature readings range around -10°C to 60°C (14°F to 140°F) while the humidity measuring range is 0 to 100% RH. You can switch the temperature readings from Celsius to Fahrenheit and vice versa. Both readings are on the screen at the same time. In addition, the hygrometer has a max/min hold function.
The portable lightweight design is the RT36 selling point. It is small enough to fit your pocket and does not feel that heavy to hold, unlike other portable hygrometers.
Other features of the RT36 is its backlit LCD screen, which makes it easy for you to look at the readings. In addition, there is an Auto Power Off (APO) feature that can shut down the device when not in use. You can turn off this feature if you need to.
- The portable lightweight design makes this hygrometer easy to carry
- Backlit LCD screen for easy reading
- APO feature helps prolong battery life
- Measurements are taken and shown in less than a minute
- Humidity reading is not accurate
- Does not take other readings such as dew point and wet bulb temperature
The digital measuring tool from ERAY can measure the ambient, dew point, and wet bulb temperature as well as the humidity of your garden. Ambient and wet bulb temperature readings range around -20°C to 60°C (-4°F to 140°F) while the dew point temperature measurements are around-50°C to 60°C (-58°F to 140°F). You can change the temperature measurement mode from Celsius to Fahrenheit with a single button.
The ERAY Digital Hygrometer takes a couple of minutes to stabilize and take its readings. Both the temperature and humidity accuracy from the unit is acceptable. It has an accuracy margin of ±0.5°C /±1.0°F for temperature and ±2.0% RH for humidity. In terms of accuracy, ERAY’s unit checks all the marks among the best hygrometer reviews.
While the hygrometer can store up to 99 groups of data, you can upload the readings to your computer. The ERAY Digital Hygrometer is compatible with nearly any Windows version, except for MAC OS.
Readings appear on a high-definition screen. It also has a backlight function to make it easier to see the readings no matter the room’s lighting.
- Ambient, dew point, and wet bulb temperature readings
- Backlight HD screen
- Ability to import data readings to PC
- Good accuracy on temperature and humidity readings
- The unit may take more than two minutes to stabilize
- Non-ergonomic design requires two hands to press the buttons
The Protmex hygrometer can give you three different temperature readings: ambient, wet bulb, and dew point temperatures. The ambient and wet bulb readings have a range of -20°C to 60°C (-4°F to 140°F) and the dew point readings range around -50°C to 60°C (-58°F to 140°F). You can change the temperature mode with just one button. The humidity readings are also on the screen along with the temperature measurements.
Accuracy is above average with a few degrees off. On the other hand, the unit can measure the temperature and humidity of the room almost instantly. If there is a large difference in temperature, the measurement usually takes less than five minutes.
Reading the numbers on the screen is easy thanks to the backlight function. There is also a Max/Min function to tell the highest and lowest readings the hygrometer took. Another major feature is the hygrometer’s ability to store up to 99 sets of data.
- Fast temperature and humidity readings
- Different temperature readings
- Data storage of up to 99 sets
- Max/Min function
- Less accurate than other hygrometers
The Mengshen Hygrometer takes a simpler approach in measuring the temperature and humidity of your garden. This tool can read the ambient and dew point temperature that ranges from -20°C to 60°C (-4°F to 140°F) as well as the wet bulb temperature with a range of around -50°C to 60°C (-58°F to 140°F).
The hygrometer’s best feature is its an ergonomic and lightweight design. You can easily fit this in your pocket and it only weighs 0.31 pounds. In addition, the layout of the buttons is set in the middle of the device. This makes it easy to reach the buttons with just your thumbs. The design of the unit allows you to use your other hands for carrying other tools or adjusting certain knobs.
The temperature and humidity readings are on a backlighted screen that is easy to read. In addition, this unit has a maximum and minimum function to keep track of any radical changes in your garden’s living area.
You can get the readings in less than a minute with this hygrometer. However, the accuracy has a slight error margin for its temperature and humidity readings when it reaches a certain range.
- The ergonomic and lightweight design makes this easy to carry
- Reads the ambient, dew point, and wet bulb temperature
- LCD screen has a backlight function
- Fast measurement of the garden environment
- Not as accurate as other hygrometers
- Does have a data saving feature
The immediate selling point of Ehdis Digital Hygrometer is its accurate reading of your garden’s temperature and humidity. Within a few seconds, the unit will give you a reading on the living condition of your plants.
This hygrometer can read the ambient and dew point temperature with a range of -20°C to 60°C (-4°F to 140°F) It also checks the wet bulb temperature with a range of -50°C to 60°C (-58°F to 140°F). The humidity measurement ranges from 0% to 100%RH with a +/-3% margin of error.
Other features of the unit include a maximum and minimum value and a backlit LCD screen. Both of these can help you with regularly checking on the state of your garden.
Another interesting to note is the size and weight of this hygrometer. This thing is only half a pound and is small enough to fit most storage pockets.
- Accurate and fast measurements of surroundings
- LCD backlight screen
- The unit can measure ambient, dew point, and wet bulb temperature
- Portable and lightweight design
- Does not have any data storing function
Amprobe’s THWD-3 Hygrometer comes from a named brand that has been making measuring tools for decades. The accuracy of the temperature and humidity is incredibly higher than other hygrometers on the list. You also get the readings in just a few seconds with this unit. This is thanks to the Sensiron SHT2x sensor of the unity.
The hygrometer covers the basic temperature readings you need to check on your garden. These are the ambient and dew point temperature that ranges from around -20°C to 60°C (-4°F to 140°F). It also checks on the wet bulb temperature as well.
The unit features a max/min measurement hold. While the screen shows both the humidity and temperature of your garden at the same time, it does not have a backlit function.
What makes this unit stand out is its extended probe stem. This allows you to insert the scanning point to small spaces or corners. You can use this feature to check on the temperature and humidity of your HVAC ducting work.
- Highly accurate readings on the temperature and humidity
- Max/min measurement function
- Can measure ambient, dew point, and wet bulb temperatures
- Extended probe stem allow for readings of ducting spaces
- Does not have a backlit LCD screen
- No option to save readings
Why Are Hygrometers Necessary for Cannabis Grow Rooms
The key to getting the most yields out of your strains comes from tweaking the temperature and moisture levels of your indoor garden. There are key points in a cannabis life cycle when they thrive in certain environments. This has to do with the development of their rooting systems and the plant’s way of reacting to the temperature of its surroundings.
During the seedling stage or a clone’s starting stage, for example, the plant benefits from high humidity percentage of around 60 – 70 percent. At this stage, the plant needs the moisture from the air because it is still growing its roots and cannot get water from the ground yet.
Throughout the plant’s vegetative stage, you want to keep the humidity below 60 percent and have a room temperature warmth in the garden for better development. As your cannabis gardens enter the flowering stage, it is a good idea to further bring down the humidity to around 30 – 40 percent while keeping the room temperature climate for better yields.
While air conditioning units will tell you the temperature it is set to, you want to make sure your grow room has the correct climate for specific stages of your cannabis plant life. A hygrometer can make sure that the environment has the right amount of humidity and is at an optimal temperature that is best for your marijuana. If you see anything wrong with the readings, you can quickly make adjustments or fix any problems with your venting system if there are any.
How to Pick the Right Hygrometers
To get the best hygrometer for your garden, you need to keep in watch several factors that are important to check on the temperature and humidity of your garden:
Accurate Readings this is simply the most important aspect of any hygrometers. A good tool will give you a correct reading at any time so you can quickly make adjustments when necessary. Hygrometers from established brands usually have the most reliable readings.
Dew Point Readings this shows the chances of water vapor occurring and creating condensation on your plants. Checking on the dew point temperature is important in keeping your cannabis buds from rotting during the late flowering stages. A good unit can give you this reading which can help you control the water vapors of your grow room when needed.
LCD Back Light when taking a reading in your grow room, you want to be able to easily read the numbers on the screen. It is often hard to see what is on an LCD screen when there are very few lights in your grow room. A backlight function will make it possible to see the numbers on the screen regardless of the lighting in the room. This eliminates the need for moving to a bright area in the room or using a secondary light to see the readings.
Data Recording monitoring any changes to the climate is important for any growers. These changes can tell you if your air conditioner is not doing its job at keeping the temperature of your grow room and may require some cleaning. Hygrometers that saves the readings you take on a specific day eliminates the need of writing the measurements on a logbook. This function makes it convenient to check on the changes and keeps all important info in one place.
Out of all the units in the list, the ERAY Digital Hygrometerstands out as the best hygrometer. The unit has all the important functions of what you need from a climate-measuring device. This includes the ability to measure the dew point temperature to control the water vapor and backlit LCD screens to easily read the measurements. In addition, the unit can also upload the stored data onto your PC so you can easily place the measurements onto a spreadsheet.
The most deciding factor in picking the unit as the top hygrometer is its accuracy. While the readings have a small margin of error, ERAY’s unit still offers a correct measurement on most grow rooms. You can quickly make any needed changes thanks to the unit’s accurate sensors.