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What Temperature Kills Tomato Plants? We’ll See!

Tomato plants exist in many varieties. Tomato is one of the most commonly consumed vegetables and the most processed worldwide.

In Ohio, the Tomato fruit is the state fruit.

So, if you’re planning to grow this all-time favorite fruit, better study the ideal temperatures where tomatoes love to grow.

This article will discuss what high or low temperatures kill tomato plants and will provide a few tips on countermeasures for the same.


What Temperature Kills Tomato Plants?

Tomato plants die when the temperature goes below the 32 degrees Fahrenheit (0 degrees Celsius) mark. Temperatures higher above 85 degrees Fahrenheit (30 degrees Celsius) affects fruit ripening, pollination, leaves curl, and the plant focuses on survival rather than growth, development, or yielding.



Ideal Temperature for the Growth and Development of Tomato Plants

Tomato plants are warm-season plants that grow at constant temperatures of between 70 degrees Fahrenheit and 85 degrees Fahrenheit  (21-30 degrees Celsius).

The temperature range is its optimum temperature at which the plant thrives well compared to temperatures higher or lower than this.


The Lowest Temperature Tomatoes Survive In

Temperatures below 50 degrees Fahrenheit (10 degrees Celsius) are too low for tomato plants.

Tomato seedlings cannot germinate below this temperature, and the process takes longer at temperatures below 70 degrees Fahrenheit (21 degrees Celsius).

Young tomato plants become stunted below 50 degrees Fahrenheit as mature plants fail to produce fruit at this temperature.

Temperatures below the 32-degree Fahrenheit mark (0 degrees Celsius) cause frost that eventually kills the tomato plant and the fruits.

Tomato plants survive up to a temperature of 33 degrees Fahrenheit (0.5 degrees Celsius), though they do not yield or grow at this point. 

Recovery from the cold injury depends on how low the temperatures drop and the extent of the damage.

Tomato plants hit by frost may have irrecoverable damage because they have freeze tissue, and their cells freeze and rupture.

This damage is identified by checking for wilting, black or shapeless plants, and fruits.

If hit by frost, allow the plant to defrost on its own. After a few hours, check on the plant to how damaged it is.


Preventing the Cold Temperature From Killing Your Tomato Plant

To prevent the cold weather from killing or damaging your tomato plants:


Always Grow the Plants During the Right Season

Grow the plants after the last frost date, when summer begins. When the growing seasons are short, grow the seedlings indoors and transplant them outdoors after the frost goes away.

Grow tomato varieties that are tolerant to a bit of cold weather. Some varieties of tomato plants, such as the Anna Russian variety and Azoychka variety, tolerate a little frost.


Cover the Tomato Plants

Cover the plants, especially at night, when certain that temperatures will drop below the tolerable temperature at night.

Water the plant before covering because a hydrated plant has a higher potential to survive cold than a dehydrated one. 

The covering could be a simple garbage bag placed on top of the plants. Use posts to keep the plastic bag out of contact with the tomato plant.


The Highest Temperature Beyond Which Tomato Plants Cannot Survive

High temperatures above the recommended 85 degrees Fahrenheit during the day and above 75 degrees Fahrenheit (24 degrees Celsius) at night could be detrimental to the tomato plant.

The temperatures would lead to failure of flower pollination that reduces fruit production. 


How to Prevent the Death of Tomato Plants During Hot Weather

The following are tips on how to stop high temperatures from killing your tomato plant.


Select the Appropriate Variety for the Region’s Temperature

Varieties such as Heatmaster, Solar Fire, Summer Set, and Phoenix are tolerant to very high temperatures and are a good choice for areas where temperatures are constantly high.

Growing varieties with short ripening periods in the growing season would be ideal for ripening before the high-temperature seasons set in.


Plant in the Right Place

The tomato plants should be grown at places where they receive the morning sun then indirect sun during the midday when the sun is scorching.

Provide shade for the plant at this time if the place doesn’t have a natural shade to it.


Shade the Tomato Plant

Shading of the plants at critical pollination times (10:00 AM and 2:00 PM) produces good yields, especially when the eastern part of the structure is left open to expose the plants to the morning sun.

The shade is made from wood that makes the frame of the structure and a drape shade cloth.


Add Mulch

Mulch such as cotton husks, straws, shredded barks, and chopped leaves are placed at 2 to 3 inches around the tomato plant to keep the soil moist.


Water the Plants

High temperature above 90 degrees Fahrenheit (32 degrees Celsius) causes adaptation of the leaves and fruits for survival.

Watering helps prevent the falling of flowers and cracking of fruits. 


Harvest the Fruits Early

Harvesting should be done before the period of intense hit sets in, and ripening allowed to continue indoors.


Temperature Effects on Plants

Temperature plays a crucial role in plant health. Most plants do well at optimum temperatures of 32-104 degrees Fahrenheit.

Excessively high or shallow temperatures could potentially injure the plants. The following are the effects of temperature on most plants:

  • Warmth is one of the four requirements for germination in plants that also include air, water, and light. The rate of germination increases with temperature rise up to a specific point upon which germination begins to decline. 

Different plants have different germination temperatures. Cold season vegetables such as lettuce and marigolds germinate at temperatures between 55-70 degrees Fahrenheit (13-21 degrees Celsius). 

  • High temperatures increase photosynthesis and respiration. When the temperatures are higher above the optimum levels, there will be an imbalance in the two processes.  
  • Low temperatures affect plant growth processes such as cell division, photosynthesis, water transport, and yielding. 
  • When the temperature is extremely low, the plant develops chill injury that could potentially kill or severely injure plants. Freeze injury is whereby water in intracellular regions freezes due to ice, leading to cell dehydration or suffocation when thick snow covers the plant surface or soil surface to prevent the entry of oxygen.


Frequently Asked Questions About What Temperatures Kill Tomato Plants


Can tomatoes thrive at 35 degrees Fahrenheit (2 degrees Celsius)?

Tomatoes survive at a temperature of 35 degrees Fahrenheit (2 degrees Celsius). Survival is a fight for a life period, and at this time, the growth and development, flowering and yielding, is halted. However, the plants are killed by temperatures below 32 degrees Fahrenheit, a temperature beyond which they get frosted, and intercellular fluid solidifies to ice, causing dehydration.


How Can I Protect Tomatoes During Cold Nights?

On nights when temperatures are as low as 30-40 degrees Fahrenheit (-1-4 degrees Celsius), cover the tomato plants with plastic bags. The cover could be as simple as garbage bags, clear plastic, or tarps. Use frost protection regularly when the cold pattern extends.


Will Extreme Heat Kill Tomato Plants?

While it’s quite bizarre, the extreme temperatures are less likely to kill tomato plants, especially when watered frequently. Shading also helps prevent scalding on tomato fruits. Tomato blossoms are most affected by hot weather and are more protected by shading. 




With the knowledge of which temperatures can destroy your tomato plants, you can now give your plant the best care possible and avoid unintentionally letting heat or cold kill it.


Author Bio

Daniel Iseli

Taking care of houseplants and gardening are my greatest passions. I am transforming my apartment into an urban jungle and am growing veggies in my indoor and outdoor garden year-round.