Tomatoes are annual plants and are grown all over the world. These are very popular because of their delicious and healthy fruits. But what if you live in a cold climate? Can you still grow tomatoes? Will the tomato plant survive a freeze?
Tomato plants are tender plants; therefore, these cannot survive a heavy frost. However, they might survive and recover from a slight freeze.
In this article, you can read about the temperatures that a tomato plant can endure, how to protect your tomato plants from frost and also, what to do if freezing occurred.
What Is the Difference Between a Freeze and a Frost?
To learn how to protect our tomato plants, first, we need to understand what we are protecting them from.
There is a difference between freeze and frost, but many people don’t know. I’ll explain it to you now.
Frost is a localized temperature drop, which might or might not reach freezing. Frost is usually happening during the night, and the next day the temperatures can rise. However, for frost to happen, there needs to be moisture as well.
When the air temperatures are dropping and meet the heat from the soil, the moisture comes into contact with surfaces. This moisture will crystallize on the tomato plants and destroys them when it melts.
Tomato plants cannot survive frost.
On the other hand, a freeze can last for several days and will affect regions. The freeze occurs when temperatures are below 32ºF/0ºC. Usually, the temperatures are lower during a freeze than during a frost.
However, tomato plants can survive a light freeze (temperatures don’t drop below 28-30ºF/-2 ºC or -1ºC, but only if there is no moisture.
What Is the Lowest Temperature Tomato Plants Can Tolerate?
The lowest temperatures tomato plants can tolerate without any problems are 50°F/10°C, however, these plants can survive down to 33°F/0,5°C. Obviously, these are the nighttime temperatures, as tomatoes need temperatures up to 70-85°F/21-29°C to grow and produce flowers and fruits.
Consistent low temperatures, which are below 50°F/10°C, affects the production of fruits because the plant cannot convert sunlight into sugars; therefore, this has low energy.
Low temperatures can also affect the process of pollination because the pollen’s production will be reduced.
Cold temperatures can cause long-lasting damage to your tomato plants, and can also kill them.
Can I Save My Tomato Plants After a Freeze?
As I mentioned earlier, tomato plants are very sensitive, especially to cold weather. These can survive a light freeze, but only if this is not accompanied by a frost
You know your tomato plant got a freeze when the leaves and stems are discolored and soft. Brown sunken leaf spots will appear as well. This is because the cold temperature destroys the cells in the plant and this leads to brown areas.
If the leaves are affected, you can pinch off these damaged leaves and make sure you prevent another freeze. However, if you see the stem is soft and discolored below the lowest leaves, then that tomato plant is gone. You can discard that plant, because it will die quickly, anyway.
When the young tomato plants got damaged by frost, you can start the planting from the beginning and you can still have tomatoes in that season. But what to do if the mature plant gets damaged and there are still fruits on it?
If this is your situation, then you can harvest all the fruits on the deadly damaged plant after the first frost. The ripen fruits can be consumed as usual, and the green fruits can be left on a window sill to ripen or you can find lots of recipes for how to use green tomatoes.
How To Protect Tomato Plants from Frost?
You can always protect your tomato plants from frost. In the early spring, you should always check the weather forecast before transplanting your seedling from indoors to outdoors. If you see that the cold period is gone, and spring is finally here, then you can transplant your seedlings.
Don’t transplant them until the temperatures are below 50°F/10°C at night-time because tomato seedlings are very sensitive and if is too cold, they can get a temperature shock and die quickly.
When a late frost is due, but you still have fruits on the mature plants, you can cover them with a frost blanket, sheets or build a greenhouse-like structure around the plants.
Before sunset, water your tomato plants, then build a structure around them with stakes or cages, and then cover them with a sheet. Don’t leave the weight of the sheet to lean on your plants because this can damage them. That is why you need the stakes.
Then on the next day, when the temperature is rising, you should uncover the tomato plants, so they can get some sunshine and fresh air. You don’t want to roast them under the covers.
Remember, when you place the sheets over the built structure, make sure this goes all the way down to the ground and are anchored with rocks or something heavy. This stops the cold air to seep under the cover.
If a heavy freeze is on its way and you know the season is over, you should just harvest all the fruits and use them in your kitchen. The mature fruits will ripen, but not the immature ones.
Wrap Up
Tomato plants will not survive a frost but they can survive a light freeze if this is not accompanied by frost.
However, you should always check the forecast so you can protect your plants from any damage. Cold temperatures will affect not only the plant but the taste of the fruits as well.
After a freeze, if you see discolored and soft stems, you have lost the tomato plant, but if the damage affected only the leaves, that plant can still be saved. However, you must ensure that no more than one freeze is affecting the plant.
You can protect your tomato plants from frost by checking the weather forecast regularly and covering them with sheets when cold weather is coming.
