Updated at: 25-10-2022 - By: Sienna Lewis

When it comes to greenhouse temperatures, here’s what you need to know:

It’s too hot in your greenhouse if the temperature reaches 90 degrees F. This temperature is too extreme for even the most heat-resistant plants and veggies. Temperatures between 80 and 85 degrees Fahrenheit are optimum for plant growth and development.

How Can You Lower the Temperature of a Greenhouse

Here are some strategies to cool down your greenhouse if it’s too hot:

Open the doors and windows

Allow your greenhouse to savor the fresh air. Roll up the plastic sheet and allow the air to circulate by opening the doors and windows or unrolling the sheet.

Use fans

For greenhouse cooling, fans are preferable over opening the doors and windows. Fresh air is drawn in by the movement of the fans. Fans should not be placed on the ceiling or ground level for this strategy to work. To move air over and through your plants, set the fans at a height of six feet or more in front of vents.

What Temperature is Too Hot for a Greenhouse - Krostrade

Use shade

Shade can also be used to help keep your greenhouse cooler. This prevents your greenhouse from being overheated by the sun’s intense heat. Use a cloth, vines, or a liquid shading compound to protect your plants from the sun and heat.

What Grows Well in a Hot Greenhouse?

Because summer temperatures soar, it’s preferable to grow plants that do well in hot climates. All they need is water, and they’ll keep producing all summer long. Plants to consider growing include the following:


Warm weather is ideal for growing greens. There are exceptions to this rule if you’re looking to speed up the growth and harvest process.


You’ll need at least two to three months of hot, sunny weather to successfully grow melons. During the ripening stage of the melons, it’s important to keep the plants moist but not soggy. Melons get tasteless when water is added in excess. It’s ideal to grow heirloom melons in hot and dry climates because of their deep roots in the soil.


Corn grows more quickly when the temperature rises. It’s important, though, to keep the soil well-watered during the growing season. A lot of water is absorbed by the kernels of corn to make them crispy and delicious.

Sweet Potatoes

Sweet potatoes may be well-known in the South, but the North is beginning to catch up. Sweet potatoes prefer hot weather, but they, too, require a consistent supply of moisture to grow. Before the soil temperature drops below 55 degrees F, pick your sweet potatoes.


As compared to sweet bell peppers, hot peppers are better at coping with long periods of high temperatures. Big Bertha, Cal Wonder, Cubanelle, and Sweet Banana are all sweet peppers that can be grown in your garden.

Top Reasons Why You Should Invest in a Greenhouse

You can regulate the climate in a greenhouse. On hot days, you can open the windows, shield your plants from heavy rain and high winds, and put up some shade to keep them from baking. You may also make sure that your plants have a sufficient amount of humidity in the air at all times.

The following are some of the benefits of purchasing a greenhouse:

Prevent pests

All of your hard work might be undone by pests and other critters. Insects, such as aphids and mites, can’t get to your plants if you keep them in an enclosed location. As a result, hazardous pesticides and chemicals would be unnecessary in the fight against these vermin.

A longer growing season

Because they maintain a more consistent temperature, greenhouses allow for a longer growing season. This extends the planting season by many months or even a few weeks for some varieties of plants.

Protect plants from extreme weather

Your plants will be protected from adverse weather conditions like heavy rain, strong winds and hail, storms and blistering heat, if you put them in a greenhouse. With this in mind, greenhouses can protect plants from temperature fluctuations.

The delicate plants can be damaged by strong winds and the sun’s rays if they are exposed. It is possible to keep your plants well-ventilated in a glass greenhouse or a similar structure with a plastic, translucent roof. Make careful to protect your plants and produce from the elements by using a greenhouse.

More plants to choose from

A greenhouse is a good investment if you wish to cultivate plants that aren’t native to your region. As previously stated, greenhouses allow you to manage the temperature independent of the weather conditions outside.

Even though it is winter, you can grow warm-season vegetables because of the warmth and insulation provided. When you cultivate plants in a greenhouse, you can modify its temperature and humidity to suit their needs. The key to growing healthy plants is figuring out what conditions they require to survive and develop.

Temperature Ideal For Your Greenhouse

When was the last time you thought about whether or not greenhouses become too hot? Yes, that’s what I’m getting at. What is the ideal temperature for a greenhouse? Plants can only tolerate temperatures up to 80 degrees Fahrenheit, and if the temperature rises above that, they may wither.

Some plants, on the other hand, can endure temperatures as high as 90 degrees Fahrenheit! Greenhouses can quickly warm themselves, so you don’t want to go too far from that.

No matter how you look at it, the following is a list of plants that are heat-tolerant and those that are heat-sensitive.

Heat- tolerant plants

The following plants can contend with temperatures as high as 90 degrees Fahrenheit, so you can share in the pleasure of the summer heat with them.

  • Eggplant
  • Okra
  • Tomatoes
  • A variety of spuds
  • Arugula
  • Cucumbers
  • Cabbage
  • Watermelon
  • Beans
  • Peppers with a fiery flavor

Despite the fact that plants are more tolerant of high temperatures, it is not necessary to allow the temperature to get above 90 degrees.

If you’re new to greenhouse gardening and don’t want to make your greenhouse too hot, you can start with these plants because they can grow even in the hottest of conditions.

How Hot Can a Greenhouse Get - Krostrade

Heat-sensitive plants

We’ll list a few plants that require special attention because they can only withstand temperatures of 75 to 78 degrees Fahrenheit.

  • Beets
  • Broccoli
  • Carrots
  • Collards
  • Cauliflower
  • Peas
  • the cruciferous vegetable
  • Kale
  • Onions
  • Lettuce

When the temperature rises above 85 degrees Fahrenheit, the following plants become sensitive. As a result, to ensure the survival of these plants, you’ll need to lower the temperature inside.

Make sure that the temperature doesn’t exceed 85 degrees Fahrenheit if you want to eat kale in the summer.

What Causes Greenhouses To Overheat?

Additionally, you should be aware that some elements can cause your grow room to generate or store extra heat. This is in addition to knowing the ideal temperature for a greenhouse. Reasons for this include:

Location of your greenhouse

It could be the location of your greenhouse that is to blame. If you’re thinking, “Well, there’s where the sun normally strikes,” keep in mind that too much sunshine can damage your plants.

You should therefore install a thermometer inside your greenhouse to keep tabs on the temperature fluctuations. In addition, you don’t want the weather to continually changing because it interferes with your plants’ ability to grow.

To keep your greens healthy, be consistent and remember to supply the proper quantity of heat, sunlight, and water.

External environment

The temperature outside your greenhouse can also influence how much heat is generated inside.

As the ground within the greenhouse warms up, it provides a better environment for your plant’s growth. It is better to turn off your heater and water your plants if the temperature is too hot outside.

If your greenhouse isn’t well-ventilated, your plants may succumb to diseases brought on by the high relative humidity.

Ways To Cool Your Greenhouse

As soon as you’ve learned everything there is to know about the highest temperature a greenhouse can withstand, you might as well add up all the ways you can reduce that temperature.

When it’s hot outside, there are many ways to keep your greenhouse from overheating. If money is an issue, fear not, since some of these require no outlay at all! More information can be found in the following paragraphs.

Ventilation system

Is it worth it? As it turns out, it’s as simple as opening your greenhouse doors or vents.

Ventilation is the simplest method of removing heat from the growing environment by enabling fresh air from outside to enter.

Using fans

During the sweltering summer months, we all utilize fans to keep cool. It works in much the same way as a ventilation system in that it facilitates the movement of air to help cool your greenhouse.

It’s time to open your checkbook if opening the greenhouse door isn’t working, because a fan can be a better option.


Simple as that sounds, placing your greenhouse in the shadow will help keep it cool. The word “shade” conjures up images of trees for most people. Because of this, having trees with enormous leaves and high canopies will be quite beneficial to you!

Instead of trees, you might use shade cloth and nettings to keep your yard cool. Aluminet is a good choice because it doesn’t raise the temperature inside your greenhouse.


Regularly watering your plants isn’t going to cut it anymore. Like people who become dehydrated from not drinking enough water or who only drink a few ounces a day, plants require extra water in hot weather.

Plants aren’t the only ones who get hot and bothered. They reduce their body temperature by evaporating water and exhaling it. As a result, they too must maintain adequate hydration.

Highest Temperature

Do you have any idea how hot a greenhouse can get? On a bright day, the temperature of the greenhouse’s walls can reach 100 degrees Fahrenheit.

Temperature control is crucial during the summer months since some plants cannot survive in harsh circumstances.

In order to maintain a healthy plant in your greenhouse, it is important to keep the temperature low. Keep in mind that excessive sun exposure can damage your plants.

What Is The Ideal Temperature In A Greenhouse?

As a fan of tomatoes and melons, you should keep your greenhouse at the ideal temperature. Your plants will thrive in a well-designed greenhouse.

At 27 degrees Celsius, a greenhouse is at its most productive. A productive harvest, increased output, and increased revenue are all contingent on this situation remaining stable.

It is critical to take the necessary precautions if you have a large number of plants because humidity and temperature might build up more quickly.

Tips For Controlling Temperatures

A greenhouse’s temperature is influenced by the presence of natural light and air movement. Unlocking the roof’s doors and windows may help cool off the building.

For those who have the money to spare, air conditioning is often installed to keep the temperature at a more bearable level.

You can open up the area by installing ceiling vents, side vents, and even a door to allow fresh air to circulate. Having a thermometer on hand might also assist you in ascertaining what the present temperature level is. When the weather is nice, don’t forget to leave windows and doors open to let fresh air in.

The growth of plants is reliant on the availability of light. Using a shaded greenhouse as a weapon against the heat can be a good idea. Shaded paints are a fast and inexpensive solution to reduce the sun’s rays.

Additionally, window coverings like blinds or shades can be beneficial. External and internal blinds are available. By allowing sunlight to be filtered out before entering the window, heat is kept inside where it belongs. It’s also removable, so you can take it off when it’s a little cooler out.

There are many ways to save money, but mesh and nets can be used as an alternative to blinds if they’re properly attached.

The greenhouse can also be dampened during periods of harsh weather. The plants are able to endure the heat because of the increased humidity. You’ll also be avoiding bugs that prefer dry environments. This is a common practice, but you must be careful not to overwater.

Tools That You Can Use In Lowering Heat

Keep in mind that if you’re having trouble adjusting the temperature, you may always use some tools. Having a thermometer in the greenhouse is an essential. You’ll be able to see a 24-hour history of the lowest and highest temperatures with just a quick glance.

You can also use an automatic vent opener to save time and effort. It does this by reacting appropriately to the actions that are taking place. Its piston expands and pushes the vent open as a nonelectric response to the high temperature.

There is nothing better than putting in a fan. Different infections can spread throughout the greenhouse when the temperature is low and there are no breezes. A reasonable amount of disease control can be achieved by using this item.

The heat will be prevented from entering the greenhouse if it is covered with a shade cloth. This comes in a variety of densities when purchased. The darker the fabric, the lower the temperature it will maintain.

How does your location affect what temperature is too hot?

It should go without saying, but keep in consideration your local climate when planning your trip.

People who live in hotter climes, for example, should pay special attention to how hot their greenhouses get.

People in Alaska with greenhouses, on the other hand, will face the opposite challenge: maintaining a warm greenhouse!

It’s important to remember that there’s more to consider than just the temperature of your area.

People who live in humid climates should pay extra attention to their greenhouse’s temperature.

Plants can suffer from fungal infections and mildew as a result of the combination of high temperatures and excessive humidity.

So, greenhouse growers, take command! Plants in hot and humid areas should be kept at a lower temperature than those in more temperate areas.

The South and Southwest of the United States, Mexico, India, the Philippines, and other countries have a hard difficulty keeping their greenhouses from overheating.

Don’t be concerned if you live in one of these climates!

We’ll talk about how to keep your greenhouse cool later on in this piece.

How to check the temperature of your greenhouse

Mercury thermometers are not recommended. Just too many disadvantages.

Mercury thermometers are inaccurate and dangerous if they are broken, making them a poor choice for thermometers.

Because of this, they’re a poor choice for monitoring greenhouse temperatures.

A thermocouple is the best way to get an accurate temperature reading.

a thermo-what?

Despite the fact that you may have never heard of a thermocouple, they’re actually quite interesting (no pun intended).

Two pieces of metal are twisted together to form a thermocouple.

The temperature difference between the twisted metal parts generates a voltage.

Is this what happened?

It’s simple to correctly measure temperature, which provides you with an accurate greenhouse temperature reading.

Which, if you still have a hankering to produce beets, you’ll require.

In order to acquire the most accurate reading, where should you set your thermocouple.

Protect your sensor from the sun and light by placing it in an area that is well-ventilated.

The thermocouple will give an incorrect reading if it is not.

The optimal location for a thermocouple is along a steady stream of air.

Make sure your thermocouple is housed in an aspirated box of reflective color to meet these standards.

Another common blunder is installing the thermocouple at the wrong altitude.

Keep in mind that heat rises: In this case, the thermocouple will read a few degrees higher than what your plants are actually experiencing.

In other words, the ideal location for your thermocouple is at or near the height of your plant.

Check your thermocouple on a frequent basis to ensure that you are aware of the greenhouse’s temperature before it gets out of hand.

In addition, make certain that your thermocouple is still in good working order and that it is situated correctly.

greenhouse | Definition, Types, & Uses | Britannica

Related Questions

How do you cool down a greenhouse?

Ventilation, shade, and evaporation are the three most common ways to keep a greenhouse cool.

There are a variety of methods available. You can open a window or vent for ventilation, or you may go fancier and use a fan.

Shade netting, shade fabric, or shade paint can all be used for shading. Fog misters, evaporative coolers, and damping down are all methods of evaporative cooling.

How can I reduce the heat in my greenhouse?

Ventilation, fans, shade cloth, shade paint, evaporative cooling, and damping down are the six most prevalent methods for reducing greenhouse heat.

The 7th option is a fog mister, which uses evaporation to chill the air.

How to regulate temperature in a greenhouse?

Temperature control in the greenhouse comprises both heating and cooling (in the winter) (in summer).

Thoughts on the Answer to “What Temperature is Too Hot for a Greenhouse?”

Make sure your greenhouse’s temperature does not reach 90 degrees F now that you know what temperature is too hot for a greenhouse. Your plants may shrivel and die if you don’t. Ascertain the ideal growing conditions for your plants and make necessary adjustments to your greenhouse.