Ferns are remarkably resilient plants that can tolerate a range of temperatures, but their cold tolerance varies significantly based on the species. Generally, many ferns can withstand temperatures down to 20°F (-6°C) or sometimes even lower. However, some tropical ferns are less tolerant and can suffer damage at temperatures below 40°F (4°C).
For example, hardy ferns like the Northern Maidenhair Fern (Adiantum pedatum) can survive in cold climates, while tropical varieties like the Bird’s Nest Fern (Asplenium nidus) need to be protected from frost.
When exposed to colder temperatures, ferns often enter a state of dormancy, which helps them conserve energy and survive until warmer weather returns. To protect ferns in colder climates, it’s a good idea to provide mulch or other insulation around their base during winter.