It is extremely important to maintain an optimal temperature in your greenhouse for the successful growth of vegetables and plants. So, which tool do you need to use to monitor temperature changes? You guessed it – a thermometer!
It is an ideal tool to use in a greenhouse to record temperature fluctuations. Most of the plants require a temperature of approximately 80° F or 27°C to grow well. The very high temperature in a greenhouse can lead to wilting and can eventually kill your plants.
Unless you are growing cacti in a greenhouse, you need to reduce the heat inside your structure promptly. Also, the temperature is not the only thing you need to worry about. It is crucial to monitor the humidity levels, so you know when to water your plants or if they are over watered.
A hygrometer measures the amount of water vapor in the air. It gives you a chance to change the conditions as required. With a hygrometer you can make sure that your flowers, plants or vegetables will always have the ideal growing conditions!
You need to take accurate records of both the temperature and humidity levels on a daily basis. That way you can keep humidity levels around 50-70% relative humidity and act fast if your greenhouse steams up. The records should be taken throughout the day and night. You can achieve that only with a good thermometer and hygrometer.
In this post I am going to share my favorite gadgets that my family has been using for years!
To be honest, with the number of gardening products we have today it is really hard to decide what to get. An indoor/outdoor thermometer is very handy to measure the temperature inside your house or a greenhouse and outside in the garden.
However, if you know that you are going to grow only in a greenhouse or at home an indoor max min thermometer is all you need. So, if this is the case, you can skip this part and head to max min greenhouse thermometers.
The best advantage of the outdoor/indoor thermometer is the ability to measure the temperature outside without you leaving the house. Also, its function is not only limited to the use in the garden and greenhouse.
For example, you can use the same device in your home to monitor the temperature changes, in places such as a storage room or a child’s bedroom.
You have two options here: wired or wireless…
Wired Indoor/Outdoor Thermometers and Hygrometers
The unique feature of this thermometer and hygrometer is that a sensor is attached to a wire. You can locate the display with the main unit in the house.
Then, you place the wire through a window or door for the sensor to take the temperature records outdoors. Wired thermometers tend to be cheaper than wireless options, like this one.
I personally like a large LCD display with 1-inch digits, so it displays the temperature readings in big numbers (especially for people with failing eyesight or for anyone really to see the readings from a distance).
It records minimum and maximum temperatures with an easy switch between Celsius to Fahrenheit and is fully waterproof. The wire is a 9.6 ft (3m) thin cable but you can make it longer – just add a speaker wire to it.
In my opinion, it is more convenient to have humidity levels measured with the temperature at the same time, as this tool does.
With a super large LCD screen display, it records the values AUTOMATICALLY and can be easily switched from F to C.
The wire is 1.5m, and the main unit can stand by itself on a back stand, or you can hang it. In addition, it comes with a clock!
If you are after a more multi-functional indoor/outdoor thermometer and hygrometer, then a wireless option is for you.
Wireless Indoor/Outdoor Thermometers and Hygrometers
The main difference from the wired model is that the sensor is not attached to a wire and is remote. You need to place the main unit anywhere inside the house and place the sensor outside.
In comparison to the wired models, you don’t need to worry about the cable being too short or too thin, which can easily break.
If you live in a bigger house, take into consideration the transmission range (should be at least 200 ft), for example, La Crosse Technology WS-916OU-IT model transmits from up to 330 ft.
Very easy to switch from F to C, can be wall-mounted and a sensor has a rain resistant casing. Unfortunately, this model does not read humidity levels, so you might check out this one.
If you are a gardening lover and are planning to invest in something special rather than just a thermometer, this tool is for you.
An extra-large LCD screen with the weather forecast, automatic clock and indoor/outdoor temperature alerts is definitely worth its price!
Max Min Greenhouse Thermometers
As the name suggests it measures the minimum temperature during the winter when frost is a big problem and the maximum temperature levels during the hot months.
Also, you need to know the temperature levels for ventilation and heating purposes.
And here starts a dilemma …
Digital or Traditional?! Wireless or Wired? Do I need to buy a thermometer separately from hygrometer or just get a multi tool?
Traditional Greenhouse Thermometer
The main difference between the digital and traditional greenhouse thermometers is that digital provides readings faster. Traditional thermometers use mercury which needs to heat up first, and then it slowly rises to show the temperature.
When my family started setting up a greenhouse there was only one type of mercury min max thermometers available. They were discontinued due to the increasing environmental and health concerns. So, we had to get rid of that one.
Now, the analog type uses a patented blue colored liquid which replaced the mercury but is as easy to use as the previous version.
However, when I was hunting for the best greenhouse thermometer, I eliminated the traditional option even though it is much cheaper than a digital one but it is definitely compromising on accuracy.
So, I would recommend getting a digital model with both thermometer and hygrometer for your convenience.
Best digital greenhouse thermometer and hygrometer:
This model has a small display but with very big numbers which are easy to read. It also has a humidity level indicator for Dry, Comfort or Wet states.
In terms of accuracy which is (+/-1 F and +/- 2-3% RH) I prefer something a little bit higher (the next product). Overall this device has a good performance.
Its biggest advantage is a magnetic backing which can be easily attached to any metal surface in your greenhouse.
If you are looking for a cheap version this tool is pretty awesome. The temperature range is from – 4 to 158 degrees F (can be switched to C) and from 1 to 99 per cent.
In comparison to the previous model, this one has a professional accuracy of +/- 0.5 F and +/-2% RH which can be manually calibrated.
Smart Greenhouse Thermometers
Now, I am going to share my personal favorite. I do like to take daily readings of the temperature and humidity levels.
Just to make sure that my greenhouse is in a perfect condition especially when planting new vegetables or flowers.
I tend to take notes but recently I came across the La Crosse Alerts Mobile 926-25101-GP Wireless Monitor System Set with Dry Probe.
It does let you to remotely monitor the temperature and humidity levels 24/7 from your phone, tablet or a computer.
You get the text and email alerts when the temperature or humidity percentage is exceeding minimum or maximum.
So, you don’t need to go and check them yourself. The device is powered by 2 AAA batteries and can be easily installed in 3 steps!
Now that you know which tool to get, I will tell you where is the best spot for a greenhouse thermometer and how to measure a temperature in a greenhouse.
Where to put a thermometer in a greenhouse?
Place a thermometer at plant level in a greenhouse, make sure it is not in direct sun. If you have plants hanging and growing on the ground, you need to put have upper and lower thermometers. Put a thermometer away from doors and don’t place it near the roof.
How do you measure the temperature of a greenhouse?
You should aim to keep a temperature inside a greenhouse around 80 to 85 degrees F. When measuring temperature of a greenhouse, keep in mind that there are 3 types of temperatures that are important for plant growth:
- Air temperature
- Plant temperature
- Soil temperature
So, to measure the temperature of a greenhouse you need to use a thermometer to measure air temperature. Then, use an infrared thermometer to check plant temperature. Finally, you need to use soil thermometer to measure substrate temperature.
Here is my 4-step guide on measuring soil temperature and I am using REOTEMP K82-3 Soil Thermometer, but you can totally use a meat thermometer to measure substrate temperature. Also, check out what other sensors I use in my greenhouse that are super affordable and save me tons of time and money every year.
I hope you found something new and interesting in this post!
Please let me know in the comments section which greenhouse thermometer and hygrometer you are using and why do you like it?
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Happy Greenhousing 🙂