As a cool weather loving crop, strawberries thrive in chillier temperatures However, frigid spring frosts can spell disaster for emerging strawberry blossoms and developing fruit Knowing the temperature thresholds and methods for protecting your plants is key to mitigating frost damage. With proper care, strawberry plants can absolutely survive light frosts. But just how cold is too cold for your berries? Let’s explore their frost tolerance and techniques to safeguard your strawberry patch when freezing weather strikes.
How Cold is Too Cold for Strawberry Plants?
While dormant strawberry plants can withstand subzero temperatures in winter, they become highly vulnerable to cold injury once growth resumes in spring. Here are the key temperatures to know:
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Tight buds tolerate down to 22°F (-6°C) – Strawberry flowers are most protected right before opening. Hard, green buds will likely survive short freezes.
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Open blooms damaged below 28°F (-2°C) – Once flowers begin unfurling, they are severely harmed by temperatures dipping under 28°F. Even brief freezes can decimate open blossoms.
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Developing fruit damaged below 26°F (-3°C) – After pollination, small green fruit suffer injury when mercury falls under 26°F. Extended exposure escalates harm.
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Leaves and runners damaged below 23°F (-5°C) – Emerging leaves and daughter plants experience tissue injury and dieback after a few hours below 23°F.
Protecting Strawberry Plants from Frost
The threat of frost damage is highest when unusually warm spring weather precedes a sudden cold snap. Luckily, strawberry growers have several tricks up their sleeves to shield plants from frigid nights:
Row Covers
Installing row covers over your strawberry patch traps heat and provides several degrees of frost protection. Use horticultural fleece or perforated plastic tunnels, securing the edges with soil or sandbags. For optimum effect, apply row covers in early evening before frosts develop.
Mulching
Spreading straw mulch over and around strawberry plants insulates roots and crowns from fluctuating air temperatures. The residual warmth from soil released overnight also bolsters protection. Wait to apply mulch until after the last hard spring freeze.
Overhead Irrigation
This commercial strawberry grower tactic involves running sprinklers all night to coat plants in a protective layer of ice. As water freezes it releases latent heat, buffering nearby plants. Turn on sprinklers before sunset and continue running all night.
Choose protected sites
Tuck strawberry plants beside buildings, walls, or trees to exploit pockets of trapped heat. Raised beds also warm faster than garden floors. South facing slopes offer better exposure to warming sun.
Cover plants
Drape bags, buckets, or flower pots over individual strawberry plants to create micro-greenhouses. Weigh covers down to prevent blowing away. Remove immediately after sunrise.
Plant cold-hardy varieties
Some strawberry cultivars better tolerate frosts, like ‘Mesabi’, ‘Sparkle’, and ‘Winona’. Ask your local nursery for chill-resistant recommendations for your region.
Caring for Frost Damaged Strawberry Plants
If your protection efforts fail and plants exhibit frost damage:
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Do not prune or remove damaged leaves and flowers. The plant may still regain vigor and damaged greenery photosynthesizes and produces food.
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Water injured plants. Freeze-dried leaves and blossoms quickly wilt. Prevent additional stress by maintaining regular irrigation.
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Apply compost tea. The microbes stimulate recovery and provide nutrients to regrow damaged tissue.
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Monitor for pests and disease. Weakened plants are susceptible to infestations. Inspect closely and take preventative measures.
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Delay fertilizing. Hold off on feeding until you gauge the extent of damage. Too much nitrogen stresses already shocked plants.
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Be patient. Have realistic expectations for reduced yield. But strawberry plants are resilient and with time may rebound better than anticipated.
Strawberry Planting Tips to Avoid Frost
While not fail-proof, strategic planting can help avoid frost damage:
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Research first frost dates for your area and plant accordingly. Choose June-bearing over everbearing varieties to avoid blooming during unpredictable spring weather.
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Delay planting 2-3 weeks past the average last frost date to avoid cold damage. Resist temptation to jump the gun!
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Pick protected sites against walls, fences, or downslopes. Southern exposures warm quickest in spring.
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Select chill-resistant varieties rated for your USDA zone. Cultivars like ‘Mesabi’ and ‘Winona’ better withstand frosts.
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Plant on raised beds which thaw faster than garden floors. Mounded rows also improve drainage.
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Use season extending devices like cold frames and mini-hoop tunnels to regulate exposure to harsh elements.
Final Thoughts on Protecting Strawberries from Frost
Freezing spring temperatures need not spell the end for eager blooming strawberry plants. Understanding their optimal climatic conditions, frost thresholds, and employing protection methods can help your beloved berries weather early season cold snaps. Remain vigilant of upcoming frosts and don’t hesitate to intervene when frigid nights threaten. With astute care and preventative action, both your strawberry plants and fruits can certainly survive light spring frosts and freezes. The reward of sweet, juicy homegrown berries is well worth the extra effort.
Due to the fact that strawberry plants grow close to the soil, and given they blossom earlier than many other crops, they are at risk for spring frost and freeze damage.
USEFUL FROST PROTECTION PRACTICES
1. What is overhead watering? It works on the idea of latent heat of fusion, which says that when water freezes, heat is released. This heat maintains the plant tissue at just above freezing. In the event that the water stops flowing at night when it is below freezing, the process goes the other way: the plant tissue loses heat and freezes. To avoid this, watering must continue until the air temperature rises above 32°F and the ice has melted. Overhead watering can be used with row covers or on its own, and it needs a calibrated emitter system to make sure that the plants always get the water they need. It has a proven track record of maintaining the temperature of the flower buds above critical temperatures. On the other hand, it could cause soils to become too wet and root diseases to spread. If the water stops at any point when the temperature drops below 32°F, the buds will freeze.
2. Row covers: Row covers are spun bonded polypropylene and vary in weight from 0.45 oz to 4 oz. Cloth sheets also work for small areas. Research has shown that using two layers of a 1 oz weight row cover provides somewhat better frost protection than a single layer of 2 oz cover, likely due to air between the layers. Heavier covers (3-4oz) work for frost protection but restrict light too much and need to be removed as soon as temperatures are above freezing. Avoid placing plastic over the rows unless it is suspended and will not touch the plants. Wherever the plastic touches the plant – leaf, flower – the plant tissues will be killed in freezing temperatures.
3. Wind machines and return stack heaters: Wind machines are expensive at first, but they may pay for themselves in places that get frost. For this system to work, there must be a temperature inversion—a weather condition in which temperatures rise with elevation, causing warm air to sit on top of cold air at the surface—and winds less than 5 mph. Acreage covered varies by model and the strength of the temperature inversion, generally 1 acre – 20 acres. Can be used with extra heat for large areas, when it’s going to be cold (in the low 20s), or when there is a weak temperature inversion. Return Stack Heaters hold approximately five gallons of fuel with 20-40 heaters needed per acre. They are effective when used alone and combined with wind machines. Light every second or third heater initially and then light the rest. These changes will let heat move through the field without a big spike in heat that could break through the inversion layer.
KEY POINTS: • If it’s cold enough, frost damage can do a lot of damage to strawberry plants, especially when the flowers are open but also to buds that haven’t opened yet. Strawberry fields are often colder at ground level than the weather forecast suggest. • Irrigation for frost protection works because heat is released as water freezes. Rates must be adjusted to account for evaporative cooling due to winds and relative humidity. When it’s windy at night, plants need more water, and not applying enough water can do more damage than not irrigation at all. • Dew point is an important factor in determining the optimum time for starting frost protection. Start temperature for frost protection is higher when humidity is low, lower when the humidity is high. • Every type of frost protection has pros and cons, so it’s important to compare systems based on your own needs.
Winterizing Your Strawberry Plants – The Definitive Guide
FAQ
What is the lowest temperature strawberry plants tolerate?
Do I need to protect strawberries from frost?
When should you cover strawberry plants?
Can strawberry plants stay outside in winter?
Can strawberries survive frost?
Whether strawberries can survive frost remains a complex question, its answer is dependent on various factors: variety selection; plant stage; cultural practices, and climatic conditions. Generally more susceptible to frost than certain other crops, strawberries challenge growers with their delicate nature.
Can strawberries grow in cold weather?
New growth on strawberries can suffer damage at temperatures below 28 degrees Fahrenheit. When the temperature is low and there is no wind frost can end up laying on the strawberry plant. Older strawberry growth will usually survive these temperatures but new leaves and flowers can be damaged.
Does frost damage a strawberry plant?
While the center crown of the plant generally will not be affected the strawberry can waste a lot of energy replacing new leaves that have been damaged by frost. New growth on strawberries can suffer damage at temperatures below 28 degrees Fahrenheit. When the temperature is low and there is no wind frost can end up laying on the strawberry plant.
How cold can strawberry plants survive?
Ten degrees Fahrenheit and below, the survival chances of strawberry plants are slim. Strawberries are at their best in temperatures of 60 – 80 degrees Fahrenheit (15 – 26 degrees Celsius) but can tolerate cold as low as 22 degrees Fahrenheit (-5 degrees Celsius), provided they are protected from frost.