Wouldn’t it be nice to get more out of your vegetable plants every year? You can, if you know which ones can survive frost and how to protect them from it.
So, does frost kill vegetable plants? Frost will kill many tropical vegetable plants, including tomatoes peppers, and squash. However, some cold-tolerant vegetables can survive frost, including broccoli, cabbage, and carrots.
Of course, a sudden frost will cause more damage than gradual cooling. If you have time to prepare, you might be able to extend the growing season by protecting your plants from cold.
In this article, we’ll take a look at which vegetables can survive cold – and which ones cannot. We’ll also go over some ways you can protect the cold-sensitive plants from cold and frost.
Let’s get started.
Does Frost Kill Vegetable Plants?
Frost will kill many tropical and warm-season vegetable plants.
- Sweet Potatoes
However, not all plants succumb to light frost.
In fact, some can survive even colder temperatures of 26 to 31 degrees Fahrenheit (-3 to -1 degrees Celsius), including:
Some of the most cold-hardy vegetable plants can tolerate temperatures of 25 degrees Fahrenheit (-4 degrees Celsius) or below.
These frost-tolerant vegetables include:
- Brussels Sprouts
Does Frost Kill Tomato Plants?
Frost will kill tomato plants, since they are warm-season vegetables. According to Rutgers University, tomatoes are very sensitive to frost, which will kill them (unless they have cold protection – more on this later).
Even a brief exposure to frost at temperatures of 32 degrees Fahrenheit (0 degrees Celsius) or below will lead to death of the plant and fruit damage.
When transplanting tomatoes outside, wait until after the danger of frost has passed. This means transplanting outside 3 to 4 weeks after the last spring frost date.
Long exposure to cold temperatures of 33 to 40 degrees Fahrenheit (0 to 4 degrees Celsius) will cause chill injury to tomato plants and their fruit, including:
- Stunted growth
- Wilted Leaves
- Pitted Fruit
Tomatoes also stop producing fruit or drop existing fruit in cold weather. You can learn more about the temperature ranges that tomato plants can tolerate in this infographic.
Does Frost Kill Potato Plants?
A light frost will not kill potato plants, but may damage the foliage. Potato plants can survive temperatures of 28 to 32 degrees Fahrenheit (-2 to 0 degrees Celsius).
However, according to the University of Maryland Extension, a heavy frost or freeze will kill potato plants. If only the foliage above ground is killed in spring, the plant will send up new growth if it has enough energy to do so.
For potatoes, wait until 3 weeks before the last spring frost date to plant your seed potatoes. That way, you will avoid heavy frost that can kill the shoots after they emerge from the soil.
Does Frost Kill Strawberry Plants?
A very light frost of 31 or 32 degrees Fahrenheit (0 degrees Celsius) will not kill strawberry plants. However, according to the North Carolina State University Extension, lower temperatures will start to cause damage:
- A temperature of 30 degrees Fahrenheit (-1 degree Celsius) will damage or kill strawberry flowers.
- A temperature of 28 degrees Fahrenheit (-2 degrees Celsius) will damage or kill strawberry fruit.
Frost will not cause long-term damage to strawberry plants, since they are cold-hardy and can survive frost in the winter.
However, if you want to avoid losing your flowers and fruit, cover strawberry plants when a late spring frost threatens (more on this later in the article).
Does Frost Kill Pepper Plants?
Frost will kill pepper plants, since they are warm-season vegetables. Any temperature of 32 degrees Fahrenheit (0 degrees Celsius) or below will damage or kill them, unless they have protection (more on this later).
When transplanting peppers outside, wait until after the danger of frost has passed. This means transplanting outside 3 to 4 weeks after the last spring frost date.
Temperatures below 55 degrees Fahrenheit (13 degrees Celsius) will slow the growth of mature peppers and stunt the growth of seedlings.
Does Frost Kill Pumpkin Plants?
Frost will kill pumpkin plants, since they are warm-season vegetables. According to the Iowa State University Extension, even a light frost will kill the vines of a pumpkin plant (although the fruit will be ok).
A hard frost will kill the pumpkin vines and has the potential to damage the fruit. The University of Nebraska-Lincoln suggests harvesting pumpkins before temperatures drop into the mid to low 20’s Fahrenheit (-7 to -3 degrees Celsius).
A spring frost can easily kill young pumpkin plants. To avoid this, transplant pumpkin seedlings outdoors 4 weeks after the last spring frost date.
Will One Day Of Frost Kill My Plants?
One day of frost can kill some cold-sensitive (warm-season) plants, including:
For this reason, it is important to keep an eye on the weather forecast. If a late spring frost or early fall frost is coming up, consider what you can do to protect your plants from the cold.
One way to protect plants from frost is to cover them with frost protection (cloches, row covers, or frost blankets).
At What Temperature Do You Need To Cover Plants?
For warm-season plants, you may need to cover the plants even before frost or freezing temperatures arrive. For example, prolonged exposure to cold temperatures below 40 degrees Fahrenheit (4 degrees Celsius) can damage tomato plants.
For plants that are sensitive to light frost, you should cover them when temperatures approach 32 degrees Fahrenheit (0 degrees Celsius). Even a few degrees of frost protection from a frost blanket can help them to survive a cold night.
For cold-tolerant plants that can handle a light frost, you should cover them when temperatures approach 30 degrees Fahrenheit (-1 degree Celsius).
For hardy plants that tolerate a hard frost or freeze, you should cover them when temperatures approach 25 degrees Fahrenheit (-4 degrees Celsius).
Should I Cover Plants At 40 Degrees Fahrenheit?
At 40 degrees Fahrenheit (4 degrees Celsius), you should cover tender, warm-season plants that are sensitive to cold, including:
Temperatures of 40 degrees Fahrenheit (4 degrees Celsius) or below can damage these plants or slow their growth.
Should I Cover Plants At 35 Degrees Fahrenheit?
At 35 degrees Fahrenheit (2 degrees Celsius), you should cover plants that are sensitive to light frost, including:
- Snap Peas
- Sweet Corn
Frost does not occur until lower temperatures, but you may have a microclimate in your garden. A microclimate is a small area whose climate is different from the surrounding area.
For example, if you have a low-lying part of your garden (where cold air settles), the temperature can be a few degrees colder than nearby areas.
Should I Cover Plants At 30 Degrees Fahrenheit?
At 30 degrees Fahrenheit (-1 degree Celsius), you should cover plants that are susceptible to hard frost or freezing, including:
A weather forecast of 30 degrees Fahrenheit (-1 degree Celsius) combined with a cooler microclimate in your yard can mean a hard frost for the plants in your garden.
How Do I Protect My Plants From Frost?
There are a few different ways to protect your plants from frost and cold weather, including:
- Cloche – a cover (often made of plastic) that protects a young plant from cold, wind, and pests. A cloche is not large enough to fit taller, more mature plants.
- Row Cover – a lightweight and flexible sheet of fabric that keeps plants a bit warmer when cold weather threatens. A row cover is long enough to protect an entire row of plants, or to wrap around an established plant.
- Cold Frame – a small structure like a mini greenhouse, used to trap heat from sunlight in the air and keep plants warm. They are not tall enough to fit taller, more mature plants.
- Greenhouse – a greenhouse is a taller structure with glass or plastic windows and roof. It can hold taller plants and keep them warmer than the outside air in both the fall and spring.
Can You Use Plastic To Cover Plants From Frost?
You can use plastic to cover plants from frost. However, you should think of it as a last resort. If you cannot get a cloche or row cover in time, then plastic might be your only choice.
According to the Utah State University Extension, keep plants from coming in direct contact with a plastic sheet used for frost cover. Otherwise, the leaves will freeze where they come in contact with the plastic.
Now you know which plants can survive frost and which ones will succumb to it. You also know how to protect your plants from cold to extend the growing season and harvest more vegetables.
I hope you found this article helpful. If so, please share it with someone who can use the information.