Lush leaves, abundant flowers, and a heavy crop of healthy fruits and vegetables — that's the goal of most greenhouse operations. Whether you're growing ornamental landscape plants for your grounds or producing ingredients for a farm-to-table kitchen, the right temperature and humidity in your greenhouse play a vital role in ensuring healthy plants and abundant harvests. Differences of just a few degrees can negatively impact plant growth and create a welcoming environment for many plant pests and maladies. Your greenhouse toolkit should include a range of sensors, tools, and other equipment to help you maintain the optimum temperature and humidity for your plants.
What's the Ideal Greenhouse Temperature for Plants?
Obviously, the answer to that question depends on the plants you're growing, but the general wisdom is that the perfect temperature for healthy plants is about 80.6 °F during the day and around 70 °F at night. That said, there's a lot of variation among the most popular plants. Here's a basic temperature chart for greenhouse plants based on how hardy they are.
||Optimal Daytime Temp
||Optimal Nighttime Temp
||Tomatoes, peppers, eggplants, cantaloupe
||70°F to 80°F
||60°F to 70°F
||Celery, summer squash, cucumbers, begonias, calla lilies
||60°F to 70°F (begonias, calla lilies)
70°F to 90°F (cucumbers, summer squash)
|55°F to 65°F
60°F to 70°F
||Geraniums, hydrangeas, beets, lettuce, carrots
||60°F to 70°F
||50°F to 60°F
||Yarrow, columbine, broccoli, peas
||55°F to 70°F
||50°F to 60°F
Maintaining that air temperature — along with ideal humidity — will promote germination, growth, and setting fruit, while discouraging many common plant maladies, such as mold, mildew and plant pests.
Let's look at different types of temperature monitoring and control tools that will help you achieve and maintain the ideal growing conditions in your greenhouse.
Types of Greenhouse Temperature Control Tools
Modern greenhouses should be equipped with a range of sensors to monitor soil and air temperature and humidity. These sensors should all link to smart hubs, which can send out alarms and interface with automated controls such as various types of ventilators, dehumidifiers, fans, and vent systems to maintain an ideal temperature. Smart home tools allow you to automate many of the adjustments needed to maintain the ideal greenhouse climate or control them via apps on your PC or mobile device.
Soil Temperature Sensors
A sophisticated outdoor soil temperature sensor can continuously monitor the soil temperature and moisture. Unlike basic soil probes, thermocouple sensors can remain in place to provide continuous monitoring and connect to wireless hubs to transmit data so you can know when the temperature exceeds or falls below your set ranges from anywhere.
Air Temperature Sensors
Air temperature affects soil temperature as well as the amount of water and air flow required by plants in your greenhouse. Multiple wireless sensors give you an overview of the air temperature throughout the greenhouse and allow you to make adjustments manually, remotely, or automatically.
Smart control apps give you even more power to leverage the temperature measurements you're monitoring and recording, but they rely on good connectivity. If your greenhouse is more than 330 feet from your router and you’re not able to use My AcuRite, then we recommend using multiple sensors to communicate with one local display to monitor conditions in greenhouses and other outbuildings on the property. Backup batteries also help protect your data and provide access to your monitoring equipment even when your power goes out.
You can combine temperature and humidity sensors with smart heating and cooling equipment to help manage greenhouse conditions from anywhere in the world. Simply monitor the greenhouse environment with AcuRite sensors, then use apps associated with your smart appliances to make the necessary adjustments. These are just a few types of smart appliances that you can use to remotely manage your greenhouse.
- Fans for cooling and air movement
- Dehumidifiers to help cool the greenhouse by reducing humidity in the air
- Door and vent controllers to open and close vents as needed
Tips for Using Sensors Effectively
- Use temperature readings from several areas in the greenhouse to get more accurate data.
- Keep the sensors out of direct sun or grow lights to avoid artificially high temperature readings.
- Place air temperature sensors at the level of the plant canopy for the best readings.
- Use thermocouple soil monitors to continuously monitor soil temperature and humidity.
- Include an outdoor weather station to keep track of the weather conditions, which will affect how hard your equipment has to work to heat and cool your greenhouse.
When you make use of modern technology to monitor and automate your greenhouse operations, you'll work less and ensure healthier, more productive plants. A little research will help you find the best temperatures for your plants and the best placement for them within your greenhouse space. By ensuring accurate data collection and usage, you'll be able to optimize your growing season to ensure your plants thrive.