Will Frost Kill Tomato Plants + {How To Protect Them]

Will Frost Kill Tomato Plants

Tomatoes are very easy to grow, making them a gardener’s favorite. Despite the wide varieties, tomatoes thrive in a warm and sunny season.

But sometimes, you can time the growing season poorly, and the incoming cold season threatens your nearly ripe tomatoes. So, you’re left wondering, will frost kill tomato plants?

Tomatoes can’t survive even in light frost or freezing temperatures. Temperatures below 50 degrees F stunt cause stunted growth, discolored, and sunken stems and leaves, and vulnerability to diseases. Nonetheless, there are ways to protect your tomato plants from frost and extend the growing season. 

This article discusses the effect of frost and how much tomato plants can survive. Still, learn tips for protecting your tomatoes in freezing temperatures until harvest.

 Keep reading.

Also Check: Can You Save Seeds From Green Tomatoes?

Will Frost Kill Tomato Plants?

Frost damages the leaves and stems, which causes wilting and darkening. At first, it may not be easy to determine the level of frost impact on the tomato plants. However, whether the frost killed the growing point or caused damage, it becomes noticeable a day after the frost.

The tomato plant and fruit cannot endure freezing temperatures, so protection is ideal when frost is nearing.

But How Much Frost Will Kill Tomatoes?

Typically, frost occurs from 32 degrees F and below. Once the plant tissues begin to freeze, frost kills the tomatoes.

New buds and active growth are primarily sensitive. Though the damage is not instant in most cases, the plant darkens, wilts and growth stops. When the water inside the tomato plant freezes, the cells expand, causing the walls to rupture and collapse.

So, will one night of frost kill my tomato plants?

Depending on the variety, soil condition, and plant vigor, a brief frost may not freeze your tomato plant. However, when extreme freezing occurs, and there’s no protection, don’t expect recovery for the plant and fruits.

So, if the tomato plant is healthy and mature, it’s likely to endure a brief freeze. However, the brief frost doesn’t spare the new shoots or fruits.

Will One Night Of Frost Kill My Tomato Plants?

Tomato plants can’t come back after frozen plants and fruits. But one night of frost won’t kill your tomato plants. They can recover if freezing occurs for a short period. After the freezing temperatures, spray with water and prune the frozen parts immediately to help the plant recover.

If the drop in temperature is just brief, there’s a good chance that the tomato plant can survive. But, the plant’s maturity is also a significant factor determining the possibility of recovery.

How likely it is for your tomato plant to come back also depends on the level of temperature drop and damage.

But if there’s frost, there’s irrecoverable damage to the plant because the plant tissues are dead.

The best thing is not to touch the plant immediately and allow it to thaw itself. Check the extent of the damage after a few hours. If the seedlings and leaves are black, there’s no coming back. Dispose of the plants and wait for the right time to plant afresh.

But what is frost? 

Frost is the drop in temperature that is likely or not to reach the freezing point. Usually, frost happens at night, and then temperatures rise when the day breaks. For frost to occur, moisture must be present.

When there’s a drop in temperature, the cold air comes into contact with the heat from the soil and the surfaces. Then, the cold moisture crystallizes on the tomato plants causing damage or even killing the plants when it melts.

Tomato plants hardly recover after frost.

What Is The Lowest Temperature Tomato Plants Can Tolerate?

Temperatures below 50°F are too low for tomato plants causing stunted growth, lower pollen production, and no fruits. Any temperature below 32°F produces frost that kills the tomato plants and fruits. 

How Do I Know If Frost Killed My Tomato Plants?

Let’s expound on how to know if frost killed your tomatoes. 

  • At 32°F and below, there’s a frost. The frost or freezing causes darkened leaves and stems, which turn brown and wilt later.
  • At 40°F and below, there’s cold damage after extended exposure. The damage includes stunted growth, wilting and sunken fruits. The plant also loses its resistance and becomes more vulnerable to disease.
  • Flowering tomato plants reduce the pollen at 50°F and below, decreasing fruit production. Also, you’ll notice a scarring defect on the fruit later in the season.
  • At 55°F and below, stunted growth and minimal fruit production occur later in the season.

Nonetheless, the tomato plant can survive even up to 33°F.

But surviving doesn’t mean the tomato plant can thrive. When it’s cold, the temperature and length of the cold determine the effect on tomato plants. The longer the exposure to cold temperatures, the worse the effects. For instance; during freezing, there’s stunted growth and the plant takes a long time to produce fruit.

If there are any fruits, expect them to freeze. In this case, dispose of them because of the permanent damage.

Fortunately, there are ways to provide cold protection to help tomato plants endure frost or freezing.

Do Tomato Plants Need To Be Protected From Frost?

Yes. Tomato plants need to be protected from frost. For tomatoes, temperature changes in late spring or early autumn result in stunted growth, poor production of fruit or flowers, and then, worst of all, death of your frost-tender plant.

As observed, tomatoes are mainly sensitive to frost. So, tomatoes are healthiest if you grow them in a lot of light and warmth.

Remarkably, there are ways you can protect your tomato plants from frost and freeze. For instance;

Garden Cloche

This plastic or glass dome covers individual plants to keep them from contracting any cold temperature.

Use your garden cloche at dusk when the temperatures drop and uncover your tomato plants in the morning to enjoy the sun. Additionally, it’s best to use the domes to cover relatively young tomato plants before they mature.

You can buy garden cloche or DIY using items in your home. For example, rigid containers like waste bins, terra cotta pots, buckets, and plastic planters would nestle in the soil to protect the seedlings.

Harvest Unripe Tomatoes

Though it’s always better to harvest ripe tomatoes, cold temperatures threaten a good yield.

Therefore, pick your tomatoes, even the immature ones, and let them ripen indoors. But, only harvest about-to-ripen tomatoes. The slightly red or light green colors make it easy to tell them apart.

After plucking, cover using a newspaper and put them in a cardboard box. When the storing temperature is around 70°F, the unripe tomatoes should take about two weeks to mature. Please make sure you check their progress daily, though.

It’s not a problem if some fail to ripen and remain green; you can make delicious green tomato recipes with them.

Row Covers 

The indeterminate variety of tomatoes starts very tiny but becomes massive by autumn. That’s why it’s best to ensure your tomato plants survive long through autumn, even when the night temperatures drop below 50°F.

Use stakes to create a tent-like structure around your tomato plants. Do also, ensure that the stakes have an appropriate length to ensure balance and even layering of the cover. Preferably, add two feet to the height of the tallest plant on an excellent stake length.

After the frame is in place, cover the structure with a garden fabric down to the soil. It would be best to add tent pegs, bricks, or stones on the edges of the fabric to ensure it stays firmly in place.

At sunrise, remove the frost cover for the tomato plants to bask in the sunshine.

Plastic Tarp

During cold nights, using a plastic sheet provides insulation against the cold. But, ensure not to touch the tomato leaves when covering the plant with the plastic layer.

This is because when it’s freezing, the plastic can transfer the frost to any part of the plant it touches, causing harm.

Water Jugs

Water holds and releases heat to the plants when they need warmth at night.

So, fill up water jugs and close the caps tightly. Burrow the jugs in the soil in an exposed spot next to the tomato plants where the sun warms the water.

When it’s nightfall, use frost covers on the plants. The water jugs gradually release heat through the night. But remember to uncover your plants at dawn to allow the jugs to trap another day’s heat.

Afternoon Watering

It would be best to water your tomato plants thoroughly before a looming frost.

Preferably, water in the early afternoon when the temperature is hot. This allows the soil to heat up before it’s cold at night.

When the soil is moist, it has a warming effect that travels upwards in the plants throughout the night.


Insulate your tomato plants with a thick layer of mulch. Before the cold season, apply about 6 inches of mulch around your tomato patch.

However, allow about an inch of exposed soil at the stalk to spread heat from the soil, reaching other parts of the plant.

When the temperatures start warming up, remove some mulch and remain about 3 inches to avoid excessive heat.

Check out the best mulch for tomatoes

Parting Shot

Will frost kill tomato plants, therefore? Like most vegetables, tomatoes hate the cold and hardly survive in frost or freezing temperatures.

As discussed above, you must check the weather forecast regularly as a gardening tradition. So, you’ll stay ahead of the game in protecting your tomato plants from the sudden temperature swings.

Saving your tomato plants is not complicated but requires timely knowledge, as seen in this guide. This way, you can grow tomatoes from anywhere.