As an autumn chill sets in pumpkin growers start anxiously watching weather forecasts. A light frost can damage vines while a hard freeze can ruin the crop. So can pumpkin plants survive frost? With proper care and protection pumpkins can endure some cold temps. But gardeners need to know what to do before and after a frost hits.
How Frost Impacts Pumpkins
Before determining how to protect pumpkins, it’s important to understand how frost damages them. There are two main ways frost harms pumpkin plants:
Freezing Plant Tissue
Below-freezing temperatures damage the living cells of the vines and fruit. As water in the plant tissues freezes and forms ice crystals, it destroys cell structures. This leads to blackened, mushy vines and ruined pumpkins.
Promoting Decay
Cold temperate also quicken the decay process in pumpkins. The thin rind of pumpkins provides little protection from cold damage. Chilled pumpkins tend to rot faster from bacteria and fungi that thrive in cold, damp conditions.
Can Pumpkins Survive a Light Frost?
Pumpkin vines are sensitive to any frost. However, mature fruit may survive a light frost with minimal damage. Let’s look at how light and hard frosts differ
Light Frost
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Temperatures Above 28°F
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Damage: Minimal. May cause surface blemishes on pumpkins.
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Recovery: Vines recover quickly once warmed. Pumpkins with minor damage are safe to harvest.
Hard Frost
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Temperatures: Below 28°F
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Damage: Severe. Vines blacken and die. Mature pumpkins suffer internal damage. Immature pumpkins rot.
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Recovery: No recovery possible. Entire crop may be lost.
So while pumpkins can survive a light frost, colder hard frosts usually mean the end of the season. Timely protection and harvest are a gardener’s best defenses.
Protecting Pumpkin Vines from Frost
When frost is in the forecast, proactive steps can shield vines and immature pumpkins from harm:
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Harvest all mature fruit – Pumpkins that are full size and have bright, hard rinds are ready to pick. Removing ripe pumpkins prevents cold damage.
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Cover vines – Old sheets, frost blankets, or cardboard can shield plants from frost accumulation on leaves. Avoid plastic sheeting.
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Provide insulation – A 3-4 inch layer of straw, compost, shredded leaves, or soil over the vines adds warmth and wards off frost.
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Water well – Moist soil retains more heat than dry ground. Ensure pumpkins are regularly watered leading up to a freeze.
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Protect roots – If hard freeze is imminent, mound 10-12 inches of soil over vine crowns to insulate roots.
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Add heat – Place old incandescent lights under shelters to provide radiant warmth. Never use open flames near dry vines.
Harvesting and Curing Pumpkins After Frost
Once frost hits, focus on saving as much of the mature crop as possible:
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Cut pumpkins from vines carefully to avoid cuts and bruises. Leave a 3-4 inch stem attached.
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Move unblemished pumpkins to a warm, sunny spot to cure for 10-14 days. Turn occasionally to prevent rotting.
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Sort pumpkins. Discard any with soft spots or damage. Use quickly or store only defect-free fruit.
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Ideal storage conditions are 50-60°F with low humidity and good air circulation.
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Inspect stored pumpkins weekly and remove any showing signs of decay. Use quickly.
Maturity Dates and Hardiness Zones
To maximize harvests before frost, know your first fall frost dates and plant appropriate varieties.
Choose early ripening pumpkins in northern zones and extend the season with late-maturing types in warmer southern zones. Reference this guide by zone:
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Zone 3-4: 75-85 day pumpkins; harvest by Sept. 25th
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Zone 5: 85-95 day pumpkins; harvest by Oct. 10th
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Zone 6: 95-100 day pumpkins; harvest by Oct. 25th
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Zone 7-8: 100-120 day pumpkins; harvest by Nov. 10th
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Zone 9-10: 120+ day pumpkins; harvest into December
Consult seed catalogs for “days to maturity” and recommended zones for each pumpkin variety.
Start Seeds at the Right Time
Timing is key when starting seeds. Pumpkins need long, warm growing seasons. Planting too early or late can limit success. Follow these tips:
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Start seeds indoors 3-4 weeks before your last spring frost date.
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Harden off and transplant seedlings when soil reaches 60-65°F.
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Delay outdoor planting until 2 weeks after the average final frost.
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Use season extending covers, if needed, to ensure the full growing season.
The Impact of Climate Change
Climate change has caused many regions to experience earlier fall frosts. Cold snaps can shock pumpkins before their typical frost dates.
To adapt, gardeners can select faster maturing varieties appropriate for the next colder zone. Adding protective covers as needed can help combat climate extremes.
Enjoying the Harvest
If frosted pumpkins are handled properly, they can still be enjoyed long after the vines fade:
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Bake, roast, puree, and freeze the flesh for pies, soups, and breads.
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Save and roast seeds for healthy snacks.
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Use uncarved pumpkins as fall décor then cook later.
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Compost vines, jack-o-lanterns, and spoiled fruit.
While an early freeze cuts the season short, gardeners can still reap rewards through timely harvests, proper curing, and storage of pumpkins. With proactive protection and management, your patch can provide hearty harvests before old man winter settles in.
FAQs About Pumpkins and Frost
Get answers to some common questions about growing pumpkins in cold conditions:
How cold can pumpkins tolerate?
- Pumpkin vines: Damaged below 30°F
- Mature pumpkins: Survive light frost down to 30°F
- Immature pumpkins: Ruined below 32°F
Do pumpkins need to be cured before storing?
Yes, curing helps extend storage life. Cure mature, unblemished pumpkins for 10-14 days in warm sunlight before storing in a cool, dry location.
Can you store pumpkins on the vine after frost?
No, leaving frozen pumpkins on dead vines leads to rapid decay. Harvest and cure pumpkins promptly after frost.
What temperature do pumpkins rot?
Pumpkins decay fastest between 60-70°F. To delay rotting, store cured pumpkins at 50-60°F. Check regularly and remove any with soft spots.
Can you replant pumpkin vines after frost?
Unfortunately, frost damage to pumpkin vines is not reversible. But the fruits of vine cuttings can sometimes be saved if the pumpkins are mature.
With proper protection and post-frost management, much of your pumpkin harvest can be salvaged even when cold temps bring an early end to the growing season.
Conclusion
While pumpkins prefer warm conditions, mature fruits can tolerate light frosts with minimal harm. But hard freezes will ruin immature pumpkins and damage vines beyond recovery. Proper harvest timing, variety selection, and proactive protection are a gardener’s best defenses against cold damage. Even if frost ends the season early, cured pumpkins still provide decor, tasty recipes, and nutritious seeds to enjoy. By understanding how to safeguard your patch against fickle fall weather, you can beat the frost and harvest a bountiful pumpkin crop.
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