Why are the leaves turning brown?

The air is likely too dry or the soil has been allowed to dry out completely.

Can I grow this in direct sun?

No, direct sunlight will quickly scorch the delicate foliage.

Plant guide

Delta maidenhair fern.

Adiantum raddianum

Pronounced ad-ee-AN-tum rad-ee-AY-num

Also known as Delta Maidenhair, Delta Maidenhair-fern, Delta maidenhair fern, Fine Maidenhair Fern

Delta Maidenhair Fern — Photo by Micki Colbeck (CC BY) via iNaturalist

This delicate fern is a favorite for its airy, lacy fronds that add a soft touch to any indoor space. It thrives in humid environments and brings a lush, tropical feel to your home. You will love how its dark, wiry stems contrast with the bright green foliage.

Another photo of Delta maidenhair fern — Photo by kiwialli (CC BY) via iNaturalist

At a glance

Care level: Difficult
Plant type: Fern
Light: Bright indirect light
Indoor light: Medium light
Water: Every 3 to 7 days
Mature size: 1 to 2 feet
Growth rate: Medium
Hardiness: USDA 10 to 12

Care

Keep the soil consistently moist and provide high humidity to prevent the fronds from drying out. If you notice brown, crispy edges, it is likely a sign that the air is too dry or the plant needs more water. Avoid placing it in direct sun, as the delicate leaves burn very easily.

Watering: Keep the soil evenly moist but never waterlogged.
Feeding: Use a balanced liquid fertilizer diluted to half strength during the growing season.
Pruning: Trim away any dead or yellowing fronds at the base to keep the plant tidy.
Repotting: Repot only when the roots have filled the container.
Soil: Peat based, well draining potting mix
Soil pH: 6.0 to 7.0
Temperature: 15 to 24°C
Humidity: 60 to 90%
Drought tolerance: Low
Lifespan: Perennial, typically 3 to 5 years with proper care.
Deer and rabbits: Moderate

Signs it needs repotting

Roots growing out of the drainage holes
Water running straight through the pot
Stunted growth

Safety

People: It is generally considered non toxic to humans.
Pets: This plant is considered non toxic to cats and dogs.
Children: The thin stems are fragile and can be easily crushed by small children.
Contact allergens: The fronds are soft and do not typically cause skin irritation.
Airborne allergens: Spores released from the undersides of fronds may cause minor respiratory irritation in sensitive individuals.
Edibility: This plant is not intended for consumption.

How to identify it

Delicate, fan shaped leaflets
Dark, wiry, black stems
Triangular, arching fronds
Lacy, fine textured appearance

Height: 0.3 to 0.6m
Spread: 0.3 to 0.6m
Leaves: bright green, evergreen
Flowers: 0cm

Problems to watch for

By symptom

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Growing it

Propagation: division, spores
When to plant: spring, summer
Overwintering: Keep the plant away from cold drafts and heating vents. Ensure the soil remains damp throughout the winter months.
In containers: It grows well in pots, provided the container has drainage and the soil is kept consistently moist.

Division

Gently remove the plant from its pot.
Use a clean knife to divide the root ball into smaller sections.
Repot each section into fresh, peat based potting mix.
Water thoroughly and keep in a humid spot.

Group moisture loving plants together to create a localized humid microclimate.

Grows well with

Peace Lily — They share similar requirements for shade and high moisture.
African Violet — They thrive in the same warm, humid indoor environments.

Similar species

Southern Maidenhair Fern — It has a similar delicate appearance but is slightly more cold tolerant.

Science

Family: Pteridaceae
Genus: Adiantum
Order: Polypodiales
Class: Polypodiopsida
Native range: Tropical and subtropical regions of South America.
Conservation: It is not currently listed as a threatened species.

It grows in the moist, shaded understory of tropical forests.

Uses: indoor houseplant, terrarium specimen, shaded patio plant

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 1/9
Nutrients: 4/9
Soil reaction: 5/9
Light: 2/9
Temperature: 8/9
Moisture: 8/9

Taxonomy resolved against GBIF.

Questions people ask

Why are the leaves turning brown?: The air is likely too dry or the soil has been allowed to dry out completely.
Can I grow this in direct sun?: No, direct sunlight will quickly scorch the delicate foliage.

Where the name comes from

The name Adiantum refers to the water repellent nature of the leaves. Raddianum honors the Italian botanist Giuseppe Raddi.

Good to know

The genus name Adiantum comes from the Greek word for unwetted.
It is commonly called the Delta Maidenhair fern.
These ferns thrive in the high humidity of bathrooms.

Also in

Low-light houseplants

Keep your delta maidenhair fern growing

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This guide was generated with AI and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.