How Cold Is Too Cold For Your Tomato Plants? The Cold Hard Facts!

By Guerrilla Homesteader

As the cold weather starts to set in, one of the biggest concerns for gardeners is how cold is too cold for their tomato plants. Knowing when temperatures are too low and what steps you need to take can make all the difference in ensuring your tomato plants survive and thrive. In this post you’ll find out what temperatures pose a risk to your tomato plants and how to protect them.

Temperatures below 50 degrees Fahrenheit are too cold for tomato plants. The ideal temperature range for growing tomatoes is between 60 and 85 degrees Fahrenheit. When temperatures dip below this range, the plant’s growth will slow down significantly and its overall health could suffer.


Tomatoes are one of the most popular vegetables to grow in home gardens, but they can be easily damaged by cold weather. When temperatures fall below 45-50°F for any extended period of time, young tomato seedlings and plants are at risk of being damaged or killed.

If you live in an area where cold weather is common during the growing season, you will need to take extra precautions when caring for your tomato plants. If possible, wait until after danger of frost has passed before attempting to plant tomatoes outdoors.

How To Protect Tomato Plants From Frost

This video shows a good “on the fly” example of a do it yourself row cover. Simple but very effective.

Optimal Temperatures For Tomato Plants

When it comes to growing tomatoes, cold temperatures can be a real challenge. Although you may not be able to control the air temperature, there are several things you can do to help your young tomato plants survive and thrive. 

To avoid cold temperatures for your tomato plants, start by paying attention to the soil temperature. Ideal soil temperatures range between 65-75°F and should remain consistent throughout the day. Daytime temperatures should also remain warm at around 70-85°F with nighttime temperatures above 60°F. It’s important to keep an eye on these factors as they will affect how well your tomatoes grow over time. 

When planting young tomato plants outdoors, it’s best to wait until after the last frost date in your area before doing so.

Tomato Vine

Protect Your Tomato Plants With Row Covers

One of the greatest challenges for gardeners in cold climates is how to protect their tomato plants during the short growing season. Even when temperatures remain consistently warm, many nights dip low enough to damage or even kill tomato plants. 

Fortunately, it is possible to protect against this through the use of row covers and other effective strategies. 

Row covers are a fantastic way to keep your tomato plants safe from cold temperatures at night. They act like blankets that cover the entire plant and trap heat near its surface, making sure that it won’t turn frigid when the sun sets. This helps ensure that your tomatoes mature properly and you get a full crop of delicious fruits instead of several green tomatoes! This one is popular and rates highly, click here if you’d like to see it.

tomato seedlings

Protecting Tomato Plants With Mulch

Layering up with compost, straw or mulch can also help insulate your tomatoes from cold nights as well as conserve soil moisture and promote healthy growth throughout their lifespan. Many gardeners use mulch to protect the plants from the elements, particularly during times of extreme weather. 

Mulch can be especially helpful when it comes to protecting tomato plants from an unexpected first frost or cold snap.

In warm climates, mulching helps keep soil temperatures more regulated and prevents root damage due to fluctuating temperatures. In cold climates, mulching also helps maintain soil temperature and keep roots insulated against extreme cold temperatures. 

cherokee purple tomatoes
Beautiful Cherokee Purple heirloom tomatoes!

For extra protection against the cold, some gardeners may choose to cover their tomato plants with protective covers such as cold frames or row covers when nighttime temperatures dip below freezing. But even with these precautions, additional insulation provided by mulch can help prevent plant damage due to frost or wind chill.

Mulching your soil can also promote and protect beneficial microbes in your soil until the colder temperatures give way to warm temperatures. Mulch can provide a number of other benefits to your tomato plants. 

transplanting tomatoes

It can help prevent soil erosion and water loss, improve soil fertility and drainage, deter disease-carrying pests, and reduce maintenance needs throughout the growing season.

Where I live in the low desert of Arizona, mulch is critical because I’m at the other side of the temperature scale. 

While I see temperatures that drop to freezing in winter, the real protection that mulch provides for me is from the extreme heat and soil drying effects of the sun. Mulch protects the soil from both ends of the spectrum. 

However, mulch should be used in addition to row covers and not in place of them when growing tomatoes in cold weather. A two pronged approach provides a better chance for success.

Is it worth it to raise a Tomato plant in a Cold Frame?

A great example of a cold frame and how great they are for thriving tomato plants in cold weather.

Protect Tomato Plants With A Cold Frame

It’s important to protect tomato plants from extreme temperatures (hot or cold) in order to get optimal fruit production. One of the best ways to do this is by using a cold frame.

A cold frame is essentially a miniature greenhouse that insulates your tomato plants so they don’t suffer from temperature fluctuations during warm weather. The structure helps keep the air and soil around your tomato plants at an ideal temperature for growth and health by preventing damaging cold temperatures.

Green Tomatoes On The Vine

Additionally, having enough light is also vital for your tomatoes’ growth, and a cold frame will help provide them with plenty of the sunlight they need to thrive. Finally, since a cold frame promotes more ideal temperatures, you can plant earlier and extend your growing season further than usual.

I would use or build a cold frame with a panel that opens to allow hot air to escape during high temperatures or sunny days. The greenhouse effect works great in cool or cold temperatures but can quickly magnify the sun’s heat during warm to hot weather also, which can harm or kill your garden quickly.

The need for ventilation is highly important when the weather heats up and you’re using a cold frame or greenhouse.

In Summary

Protecting your tomato plants from cold weather or a cold climate is an important part of caring for them and protecting your harvest. If you experience low temperatures, you may need to provide extra protection with row covers or even moving potted plants indoors.

Additionally, mulch can be a great way to add insulation and extra warmth for plants during cold nights. Finally, don’t forget to check the weather forecast so that you can be prepared if temperatures start dropping.

You may not be able to control the weather, but you can protect your plants from frost damage and chilly temperatures. If a deep freeze or hard frost is expected, cover your tomato plants with sheets or blankets to keep them protected if needed.

Make sure that the materials you use are breathable so they don’t suffocate the plant and always remove them during the day when temperatures rise. By taking appropriate precautions described in this article you can keep your tomato plants safe and productive even when the weather turns cold.

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Links To Related Tools And Resources

MCombo Greenhouse Wooden Cold Frame

Valibe Plant Covers Freeze Protection 10 ft x 30 ft

References

https://extension.unh.edu/resource/growing-vegetables-tomatoes-fact-sheet-1

https://njaes.rutgers.edu/fs678/

https://extension.arizona.edu/growing-tomatoes

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