As temperatures drop in fall, a common concern for home gardeners is whether their unharvested butternut squash can survive frost. While butternut squash vines are quite sensitive to frost, the fruit itself is surprisingly hardy when it comes to cold temperatures. With some simple protective measures, you can increase the odds of your beloved butternut squash thriving through frosty nights.
How Cold-Hardy Are Butternut Squash Plants?
To understand how frost impacts butternut squash, it helps to know that the vines and fruits have very different tolerances:
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The vines, stems, and leaves of butternut squash are tender and will be damaged by temperatures below 32°F. Even a light frost will cause them to blacken, wilt, and die back.
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On the other hand, the squash fruit itself can generally tolerate temperatures in the low 30s thanks to its hard outer rind. Prolonged freezing will damage the fruit, but brief frosts are usually survived.
So while the foliage gets taken out quickly by frost, the squash you worked hard all season to grow will likely be just fine under the same conditions. Focus protection on the ripening fruits still on vines rather than the leaves and vines themselves.
Signs of Frost Damage on Butternut Squash
It’s easy to assess whether your butternut squash has sustained true freeze damage after a frost:
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Squash that has frozen will appear water-soaked, mushy, or collapsed where damaged by ice crystals rupturing cells.
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The rind may also darken or wrinkle at sites of freezing. Frozen sections will quickly rot once thawed.
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In contrast, unfrozen butternut squash will remain firm, bright, and unblemished after frost touches the vines. The rind resists light freezing.
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Another clue is the condition of the vines. If leaves are blackened but fruit is still firm the squash likely survived undamaged.
The fruits’ appearance and texture will reveal whether frost was severe enough to harm the squash itself
Protecting Butternut Squash from Early Frost
If frost threatens your unfinished butternut squash, here are some tricks to shield the fruits:
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Cover plants with fabric row cover, straw, or old sheets before frost forms. Remove cover daily so plants can photosynthesize.
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For larger vines, drape plastic sheeting or tarps over metal hoops to create a protective tent.
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Harvest squash showing mature tan rinds since these ripen off-vine if frost damages vines. Underripe green squash won’t continue ripening easily.
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Insulate soil with hay or other mulch around base of plants to prevent ground from freezing and harming roots.
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Water well 1-2 days before expected frost to keep plants hydrated and better able to handle cold stress.
With adequate safeguards, even temperatures in the 20s and 30s can be survived by the butternut fruits. Just be ready to harvest once vines are too damaged to support continued growth.
When to Harvest Butternut Squash After Frost
Ideally wait to pick butternut squash until the rind is tan and resists puncture from your fingernail, signaling full maturity. But once frost ravages vines, fruit needs harvesting even if some squash are not fully ripe:
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Pick any tan, mature squash promptly after frost since they won’t continue ripening off the dead vines.
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Immature green squash should also be harvested if vines are wholly killed. Discard any with frost damage.
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Try curing the unripe squash in a warm area to improve flavor and sweetness. Curing involves holding them at 80-85°F for 1-2 weeks.
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Expect that uncured green butternut squash may not store as long or taste quite as sweet. But they’re still usable!
Don’t leave fruits out in the garden on frost-killed vines where they’re vulnerable to rotting, pests, and further cold exposure. Get them picked and enjoy your early winter squash harvest!
Storing Butternut Squash After Frost
Butternut squash that avoid frost damage store just as well as unweathered fruits. To maximize their storage life:
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Cure mature, undamaged fruits for 10-15 days in a warm, dry area before final storage. This toughens rinds and healing any superficial wounds.
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Store cured, undamaged squash in a cool (50-55°F) location like a basement or cellar. Avoid temperature fluctuations.
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Periodically check for soft spots or mold growth and discard any damaged fruit. Most will last 2-3 months if properly cured.
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Refrigerate cut squash pieces within a week of cutting to prevent spoilage. Cooked mashed squash also refrigerates well.
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Freeze any extra cubed or cooked squash for longer term storage and enjoying that homegrown flavor year-round!
Growing Frost-Resilient Butternut Varieties
Some butternut squash varieties have been selectively bred to mature earlier and possess improved cold tolerance:
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‘Early Butternut’ matures about 2 weeks sooner than traditional butternut types. Quicker maturity reduces exposure to fall frost.
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Hybrid varieties like ‘Atlas’ and ‘Avalon’ also feature shorter growing seasons along with disease resistance.
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Look for descriptions mentioning improved cool weather performance or vigor during periods of cold stress.
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Consider trialing short-season varieties if frost consistently threatens your ripening squash crops.
Selecting fast-maturing butternut cultivars reduces the risk of damaging fall frosts cutting your harvest short.
The Takeaway on Butternut Squash and Frost
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Butternut vines and leaves are very sensitive to frost but the fruits have some cold tolerance once mature.
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Watch for water-soaked or mushy spots to discern if freezing has damaged the squash flesh.
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Shield plants from frost with covers and harvest mature fruits promptly after frost.
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Cure and store undamaged fruits properly to enjoy for months after harvest.
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Choose short-season varieties to avoid frost killing vines before the squash fully ripen.
With some frost protection measures and prompt harvesting, you can still get an abundant butternut squash harvest even if cold weather arrives early!
Harvesting squash and pumpkins: get them while they’re good
Gretchen Voyle, – September 16, 2011
Take the right steps, watch the thermometer, and know when to harvest to keep your squash and pumpkins from getting frosty or frozen.
For many people who garden at home, the season is almost over, and they’ve picked and eaten many tasty fruits and vegetables. Still, a few need to be picked, and it’s important to do so at the right time.
Right now, winter squash and pumpkins are maturing before harvest. To store well, their skin or rinds need to be strong and tough. Many winter squash can stay fresh until early spring if they are kept at the right temperature and humidity. Unfortunately, pumpkins don’t have a rind that gets as hard, so they usually start to go bad after the winter holidays.
The biggest worry is frost or freezing temperatures. Some leaf vegetables, like Swiss chard, kale and collard greens, are actually made tastier by light frosts. Others, like beets, carrots and turnips that are below ground, will not notice a temperature dip. But those rinds that need to be strong and tough to store over the winter can be ruined.
Squash and pumpkins that have frosted or frozen begin to decay as soon as they have thawed. They might not be usable right after a heavy frost, and their protective skins won’t hold up for long periods of time. The smart gardener keeps an eye to the thermometer and the weather reports. If frost is expected, covering winter squash and pumpkins can make the difference between harvesting and composting. Any temperatures that are projected to drop into the mid-30s should make a gardener’s frost alert kick in.
Squash and pumpkin plants can be covered with old sheets, blankets or quilts. Newspapers that are weighted down or broken-down cardboard boxes could also be used to cover plants. The one thing that will not protect and could cause worse damage is covering with plastic. Plastic sheeting or tarps create moisture vapor below the covering and plants freeze under the supposed protector. If the temperature drops lower than 32°F, it may be almost impossible to protect the squash and pumpkins. Picking them is the only option left open.
If frost is not an issue, winter squash or pumpkins can be harvested when the plant’s leaves die. When the plants are done growing and leaves have shut down, fruit can be removed at any time. If the ground they are sitting on is damp or wet, they should be taken off as soon as possible.
Be sure to cut the fruit loose with a section of stem attached at the top. Those squash that have stems broken flush with the top can decay in this area. If pumpkins are not being stored for very long, this may or may not be an issue. But harvest them correctly and enjoy the fruits of your labor with lots of butter. Related Source: Gardening in Michigan Website
Can you freeze butternut without blanching?
Can butternut squash survive frost?
When it comes to frost and butternut squash, the key is to protect the plants from the cold temperatures. Here are some steps to ensure that your garden is protected from frost damage: Plant butternut squash in late summer or early fall, so that the plants have time to mature before the cold weather sets in.
Is winter squash frost tolerant?
Weather and frost will also dictate harvest time. Despite the name “winter squash”, butternuts, pumpkins, and other hard squash are NOT frost tolerant. The vines are susceptible to frost injury, as is the fruit itself. If winter squash are exposed to frost the protective rind becomes damaged, which compromises its long-term storage ability.
When should I insulate my winter squash & Butternuts?
If just a light frost is in the forecast, you may be able to insulate the plants and fruit with frost cloth or other protective covers. If your winter squash or butternuts do get frosted, harvest and use (or preserve) them as soon as possible. Mid-November in our fall-winter garden.
Can squash plants survive in cold weather?
However, squash plants can still survive in temperatures outside of this range. According to the University of California, squash plants can tolerate temperatures down to 32 degrees Fahrenheit (0 degrees Celsius). Anything below this temperature can lead to injury or death of the squash plants.