Can Ferns Survive Frost? Cold Tolerance Explained

By Marcus Williams · January 23, 2026

Can Ferns Survive Frost?

Most ferns cannot survive frost. The majority of fern species are sensitive to freezing temperatures and will suffer cellular damage when exposed to temperatures below 32°F (0°C). However, some cold-hardy species like Polystichum acrostichoides (Christmas fern) can tolerate brief frost exposure in USDA zones as low as 3.

Understanding Fern Cold Tolerance

Ferns are ancient vascular plants that thrive in moist, shaded environments. While they are resilient in many conditions, cold weather presents a significant challenge. Frost causes ice crystals to form within plant cells, rupturing cell walls and leading to irreversible damage.

Factors Affecting Frost Survival

Species variation: Tropical ferns (e.g., Boston fern) are highly frost-sensitive, while temperate species may endure light frosts.
Maturity: Established ferns have better cold resilience than young or recently transplanted ones.
Duration of freeze: Brief overnight frost is less damaging than prolonged sub-freezing temperatures.
Microclimate: Sheltered locations (e.g., under tree canopies) offer protection from wind and frost.

Cold-Hardy Fern Species

Not all ferns are equally vulnerable. Some species have evolved mechanisms to withstand colder climates. These include:

Polystichum acrostichoides (Christmas fern) – USDA zones 3–9
Dryopteris erythrosora (Autumn fern) – USDA zones 5–8
Matteuccia struthiopteris (Ostrich fern) – USDA zones 3–7
Athyrium filix-femina (Lady fern) – USDA zones 4–8

Protecting Ferns from Frost

Practical Winter Care Tips

Mulching: Apply 2–3 inches of organic mulch around the base to insulate roots.
Covering: Use frost cloths or burlap to shield fronds during predicted freezes.
Watering: Water before expected frost; moist soil retains heat better than dry soil.
Potted ferns: Move containers indoors or into a greenhouse when temperatures drop.

Fern Species	Common Name	USDA Hardiness Zone	Min Temp Tolerance (°F)	Frost Resilience
Polystichum acrostichoides	Christmas Fern	3–9	-40°F	High
Matteuccia struthiopteris	Ostrich Fern	3–7	-40°F	High
Dryopteris erythrosora	Autumn Fern	5–8	-20°F	Moderate
Athyrium filix-femina	Lady Fern	4–8	-30°F	Moderate
Nephrolepis exaltata	Boston Fern	9–11	45°F	Low
Cyrtomium falcatum	Holly Fern	7–10	10°F	Low-Moderate

Table data source:1, 2

The data shows a clear correlation between USDA hardiness zone and frost tolerance. Ferns adapted to zones 3–5 can endure extreme cold, while tropical species like Boston fern require protection below 45°F. Ostrich and Christmas ferns exhibit the highest frost resilience among common garden varieties.

Signs of Frost Damage in Ferns

After a freeze event, monitor for these symptoms:

Blackened or brown fronds
Limp, wilted foliage
Failure to unfurl fiddleheads in spring
Mushy rhizomes when excavated

If only fronds are damaged, the plant may recover from the crown. However, rhizome death typically means the fern won't survive.

Frequently Asked Questions About Ferns and Frost

Can I leave my outdoor ferns outside during winter?

Yes, if you grow cold-hardy species like Christmas or Ostrich fern in your USDA zone. For tender species or potted ferns, bring them indoors or provide heavy mulching and cover.

Will frost-damaged ferns come back in spring?

Sometimes. If the rhizome (underground stem) remains firm and white, the fern may regrow. Trim dead fronds and wait until late spring to assess recovery before removing the plant.

What temperature kills ferns?

Tropical ferns begin suffering damage below 45°F. Temperate species vary, but sustained temperatures below 20°F can kill even hardy types if unprotected. Sudden freezes are more damaging than gradual cooling.

How do I protect potted ferns from frost?

Move containers to a garage, porch, or greenhouse when frost is forecast. Alternatively, group pots together, wrap the sides with bubble wrap, and cover the foliage with a frost cloth overnight.

Do ferns go dormant in winter?

Many temperate ferns enter dormancy in winter, dying back to the ground and resprouting in spring. Tropical ferns don’t naturally go dormant and require consistent warmth and moisture year-round.