Can Beets Survive Frost
I read a lot of different information over the years about how frost-hardy beets really are. The truth is that the hardiness of beets differs depending on each beet’s growth stage.
Can Mature Beets Survive Frost
Overall, beets are semi-hardy vegetables. As they mature they become more cold-hardy. That’s because once they have leaves, they can manufacture sugar, which acts like antifreeze does in a car.
Mature beets can tolerate about 50% of their internal water in the form of ice. That’s much higher than most vegetables like beans which is around only 10%. (USDA)
Certain types of beets are more cold-hardy than others. The internet will tell us that beets can only survive temperatures down to 28°F, but I’ve found that varieties like Bull’s Blood, Early Wonders, and Chioggia can survive down to 20°F before the temperature is lethal.
Lutz Greenleaf and some white varieties were able to withstand temperatures down to 15°F and Formanova’s didn’t die until the temperature was 12°F.
Keep in mind that those are air temperatures, so the soil could have been up to 10° warmer. Soil tends to hold heat better than air.
Some gardeners are even able to grow beets under a row cover when the air temperature is only 10°F.
Remember that these are mature plants and this changes significantly with seeds and seedlings.
What Happens to Beets During a Frost
If your beet plants get hit with frost, the tops may die, but the roots will survive. Mature beet plants are pretty hardy and can tolerate repeated light frosts.
Even if the tops die, you can harvest the root and it will still taste great. Even if they’re small, they still taste the same. In fact, baby beets are prized among chefs.
Can Beet Seedlings Survive Frost
Seedlings are more susceptible to frost damage, especially after the seed germinates and before it emerges from the soil.
The US Department of Agriculture did a great survey on sugar beets from seed to seedling, examining their tolerance to cold at different stages of growth. Here’s a brief recap of what they found.
Once a beet seed germinates, it will survive soil temperatures as low as 27°F. But as the seedling puts down roots and is 1/2 inch below the surface (it hasn’t emerged yet), it will die at a soil temperature of 31°F.
In other words, there is a window between germination and seedling emergence where beet’s cold hardiness gets worse.
That’s because as I discussed earlier, it hasn’t formed leaves that can soak up sunlight and create salts and sugars which help protect it from the cold.
Once the seedling emerges and has developed cotyledons (seed leaves that come in before true leaves), it can withstand temperatures as low as 28°F but the stem is particularly susceptible to frost damage.
What does this mean? The best way to screw up growing beets is to plant them at the wrong time. Knowing when to plant beets is really important. And contrary to popular belief, it is very possible to start beets indoors and transplant them outside later. I’ve done it with no problems.
Can Beet Seeds Survive Frost
Yes, beet seeds prior to germination can withstand freezing temperatures. I know some people who even keep their seeds in the freezer - just don’t freeze and thaw them too many times or you’ll stress them out. And stressed out beets don’t do so well in the garden.
Planting beet seeds in ground temperatures that are freezing will not kill them. They will not germinate though until the soil temperature is at least 40°F.
What you want to avoid is seedlings being exposed to frost, because that is when they are most susceptible to death.
Do I Need to Cover Beets for Frost
If your beets have just begun to sprout and you have reason to believe the soil temperature will drop below 30°F, I would take measures to protect them including installing a floating row cover. I’m currently using this 10x30 ft row cover made from fabric to cover several of my garden boxes and it’s held up great for several years.
I highly recommend a soil thermometer because basing these measures based on air temperatures is usually wrong in my experience.
You don’t have to geek out like me on measuring soil temperatures, but I’ve been measuring my soil temps two times a day for years and I can tell you that the soil temperature can vary by 10° to 15°F on average compared to the air temperature.
The one I linked to above I’ve had for several years now and it has worked with no problems. It’s digital and is easy to read. It also measures sunlight, moisture, and pH.
Another trick I’ve learned over the years is to use fertilizer. Fertilizers with salt or potassium nitrate can increase the cold survival of many vegetable plants by a couple of degrees. Using Langbeinite or even Potash will do the trick and can buy you some extra degrees. My preference is usually Langbeinite with beets because it’s a bit less lethal than potash.
Whenever I do this, I’m always cautious that I’m not trading one problem for another by overfertilizing my beets.
What Temperature is Too Cold For Beets
Beet seedlings can survive temperatures as low as 31°F. Mature plants can survive temperatures as low as 15°F for some varieties.
Can Beets Stay in the Ground After Frost
Yes, they can. But if the ground temperature fluctuates too much between freezing and thawing, it can ruin your beets.
Can Beets Survive a Frost Recommended Reading
When to Plant Beets
