Maidenhair Ferns (Adiantum raddianum) are among the most delicate and beautiful ferns. The fronds of this plant appear almost lacy, with long stems that grow in a symmetrical pattern with rounded lobes giving it a graceful and elegant appearance that makes it perfect for home decor. It is a popular choice for terrariums, bathrooms, and other areas where humidity is naturally high.
There is a lot of misinformation out there about maidenhair fern care. Many people are under the impression that maidenhair ferns are hard to care for, difficult to grow, and will only survive if they are pampered. None of this is true! Maidenhair ferns are some of the easiest plants you can grow indoors.
Plant Profile
| Common Name | delta maidenhair fern, maidenhair fern |
| Scientific Name | Adiantum raddianum C. Presl |
| Synonyms | Adiantum cuneatum, Adiantum cuneipinnulum, Adiantum cyclosorum, Adiantum mexicanum, Adiantum rubellum, Adiantum weigandii |
| Family | Pteridaceae |
| Genus | Adiantum |
| Type | Ferns |
| Native Range | Tropical Americas |
| Common Cultivars | Fritz Lüthi, Fragrantissimum (fragrant fronds), Brilliantelse, Kensington Gem |
| USDA Hardiness Zones | 9b-11 |
| Mature Size | Height: 1-2 ft; Spread: 1-2 ft |
| Bloom Time | Non-flowering |
| Foliage | Evergreen |
| Propagation methods | Division, Spores |
| Sun | Indirect light, part shade |
| Soil | Moist and well-drained; neutral or slightly alkaline soil |
The genus name Adiantum is derived from the Greek adiantos, meaning “unwetted,” and refers to some species’ fronds that repel water. The species name raddianum is derived from Giuseppe Raddi, an Italian botanist who was the first to describe this fern in 1806.
The true “maidenhair” is not just a pretty name. It refers to the resemblance of the leaves to hair. This is one fern you can show to kids without fear they’ll be frightened by its spooky, unfriendly appearance!
Maidenhair Fern Care
Maidenhair Ferns are popular houseplants because they’re hardy, easy to care for, and tolerant of a wide range of indoor conditions. However, these plants do need some attention in order to grow well indoors.
When caring for maidenhair ferns, remember that these plants originate from the tropics and need a humid environment. Maidenhair ferns are fairly low-maintenance when it comes to watering, but they do need moist soil at all times. Use room-temperature water when you water them and make sure that the potting mixture always stays damp, but not soggy or wet.
Light and Location
The natural habitat of most ferns is in the shady, moist understory of wooded areas. Ferns do not have any way to move water up to their stems like most plants. Instead, they depend on trickling water and rain for their source of moisture. As a result, they are susceptible to extreme light variations and require shade or indirect sunlight. Maidenhair ferns do not like full hot sun and will scorch and die rapidly.
Avoid locations that receive bright, direct sunlight. Also, keep it away from heat registers, air-conditioning vents, and drafts. Maidenhair ferns thrive in moist conditions (60-80% relative humidity) and like temperatures of about 70 degrees Fahrenheit, making bathrooms and terrariums perfect locations.
Watering and Feeding
Soil humidity is crucial to the health of maidenhair ferns. Maidenhair ferns require high moisture levels, but they will perish if left in soggy soil for too long. Water every day until the soil is damp but not sopping wet. Make sure there is good drainage to avoid root damage.
Maidenhair ferns also need a half-strength dilution of general-purpose fertilizer every month or two during the spring and summer. This can be omitted in winter when there are no new fronds to feed. Use a water-soluble, time-release fertilizer for best results.
Temperature
Maidenhair ferns are not demanding plants. As long as the temperature is moderate and there is good light, humidity, and water, they will grow well. They can survive temperatures of about 40 degrees Fahrenheit, but their optimal environment is approximately 70 degrees during the day with a 10-degree drop at night.
Over-wintering Maidenhair Ferns If you live in an area with cold winter temperatures (32 degrees Fahrenheit or below), it is essential to bring maidenhair ferns indoors before the temperature drops. They will not survive freezing temperatures for more than a few hours.
Keep the plant in a cool room (60 to 70 degrees Fahrenheit) for at least one hour before returning it to its typical environment. If you live in an area where maidenhair ferns cannot be grown outdoors, you can keep them potted and indoors year-round.
Humidity
Maidenhair ferns need high humidity to survive. One way to increase humidity is by placing a small dish of water underneath or near your plant. Placing a humidifier close to the plants will also have the same effect.
Keep a small pump spray bottle filled with water and lightly mist your maidenhair ferns a few times a day. It will mimic the natural fog and rain they would receive in their native habitat and provide much-needed humidity. You can also keep them on a pebble tray with water to increase humidity even further, although this is unnecessary if you use other methods.
Repotting Maidenhair Ferns
Repotting maidenhair ferns can be done in the spring to encourage new growth or in the summer if the plant is growing too large. The size of the container you put your maidenhair fern in should be slightly larger than what it was previously. To make a maidenhair fern smaller, remove about a quarter of the roots and replant it in its original pot.
When repotting a fern, take a minute to examine the roots. Healthy roots have light brown or white growing tips. If the roots are black, they’re dead and should be trimmed away to protect the health of those that remain.
Maidenhair ferns do not have an extensive root system, so moving them to a larger pot is not often necessary. If they are grown in small pots, it is best to repot them every two years with fresh, well-balanced soil. If they are in a larger pot, you can let them go for as long as three years.
Propagation
Maidenhair ferns can be propagated by dividing the rhizomes. First, carefully remove the plant from its pot and use a sharp knife to separate the divisions. Next, repot each division in its own container with fresh soil.
Common Pests
Maidenhair ferns do not have serious insect or disease problems. The most common issues with maidenhair ferns are scales and mealybugs, which can cause damage to the foliage. Check the plant regularly for these pests and remove them as soon as they are spotted. The easiest way to deal with them is to wipe the leaves gently with insecticidal soap or horticultural oil.
Common Issues
Maidenhair ferns are relatively low maintenance and do not have a wide range of problems:
Fronds turning brown and crispy
When fronds turn brown and crispy, it may be a sign of low humidity, proximity to a heater, or bright direct sunlight. Try moving the fern to a shadier or cooler location. Also, try misting it daily or running a humidifier in the room.
Leaves turning pale
If the leaves are turning pale, it may signify that there is too much direct sunlight. The plant may also need feeding.
Fronds turning yellow and limp
Too much water, not enough water, or soggy soil can cause this problem. Make sure to provide good drainage and check the soil before watering.
How To Grow a Maidenhair Fern – Useful Tips (Video)
FAQ
Are maidenhair ferns toxic to cats and dogs?
No. Although the houseplants should be kept out of reach of pets and not recommended for consumption, maidenhair ferns are not considered toxic for pets.
Can maidenhair fern grow outside?
Maidenhair ferns cannot be grown outside in areas where the temperature falls below freezing. However, they can be grown indoors year-round if given proper conditions.
How to revive a maidenhair fern?
If your maidenhair fern dries out and its fronds turn brown, there is still hope. You can try to refresh the soil and prune the roots before repotting. Remove about a quarter of the old potting mix and replace it with a new potting mix. Cut off the brown fronds at the soil level, and keep the soil moist. The plant may re-grow after a few months.
Is maidenhair fern a perennial? How long do they live?
Maidenhair fern is an evergreen perennial that does not flower and die in one season. This plant will live for many years as long as it gets the right conditions, such as moist soil (but drains well), water, and partial shade or indirect sunlight.
How to care for maidenhair fern outdoors?
You can plant maidenhair ferns outdoors in USDA hardiness zones 9b-11. They are susceptible to frost, preferring temperatures above 60 degrees Fahrenheit (16 degrees Celsius).
Plant maidenhair ferns outdoors in rich, humusy soil that drains well. They are especially fond of places with moist, humid air but never allow the plant to sit in water because it can cause root rot.
Is maidenhair fern invasive?
Maidenhair fern has become naturalized in various tropical and subtropical islands. It is considered to be an invasive species in Hawaii and French Polynesia.
Pteris lidgatei and Dubautia plantaginea sub. humilis are two endangered plant species native to Hawaii that are threatened by the spread of A. raddianum.
How big can maidenhair fern grow?
Maidenhair Ferns are relatively small; they can grow up to 16 to 18 inches tall and spread up to 22-23 inches wide.
References
André Karwath aka Aka, CC BY-SA 2.5, via Wikimedia Commons