Demanding Fern Safe for pets

Maidenhair Fern

Adiantum raddianum

An extremely delicate fern with airy fronds composed of tiny tender green leaflets carried on black, hair-thin petioles.

The essentials at a glance

Watering

Every 3 days
Light

Medium light
Humidity

60–80 %
Temperature

15–25 °C

How to care for your Maidenhair Fern

Everything you need to keep your Maidenhair Fern healthy: watering, light, humidity, feeding, repotting and pruning.

Adiantum raddianum is a tropical fern renowned for its exceptionally fine and lightweight foliage. Its delicate fronds are composed of tiny fan-shaped leaflets in luminous tender green, carried on glossy black petioles as thin as hair. It is one of the most demanding houseplants, requiring consistently high humidity and a never-dry substrate. However, for those who take on the challenge, it offers a botanical display of unmatched grace, transforming any space into a small corner of tropical forest.

Watering your Maidenhair Fern

Every 3 days

Keep the substrate constantly moist but never waterlogged. Never allow to dry out completely — even a single drying episode can kill the fronds. Water with water at room temperature, ideally non-calcareous.

How to know it needs water

Top of substrate beginning to dry
Fronds beginning to curl
Leaflets becoming crispy and brittle

How much light a Maidenhair Fern needs

Medium light

Moderate to diffused indirect light. Never expose to direct sun which instantly scorches the delicate fronds. Ideal in a bright bathroom or near a north-facing window.

Direct sun tolerated: No direct sun
Orientations that suit it: North, North-east, East, North-west

Humidity and misting

60–80 %

High to very high (60–80%). This is the primary requirement of this fern. Dry air is its worst enemy. Mist daily or even twice a day in summer or when heating is active. Use water at room temperature. A tray of damp clay pebbles or a humidifier is strongly recommended.

Feeding and fertiliser

Every 14 days

Fertilize very lightly fortnightly from spring to autumn. Adiantum roots are very sensitive to fertilizer burn. Do not fertilize in winter.

Recommended feed: Liquid foliage plant fertilizer diluted to a quarter of the recommended dose. · 1-1-1

Repotting your Maidenhair Fern

Every 18 months

Use a plastic pot (retains moisture better than terracotta). Rich, humus-rich substrate: potting soil, peat, perlite, and a little sphagnum moss. Do not compact. Keep moist after repotting.

When: Spring
Potting mix: All-purpose potting mix
Mix in: perlite, sphagnum moss, coco fibre

The tell-tale signs

Black fibrous roots filling the pot
Substrate drying out very quickly
Plant producing far fewer new fronds

Pruning your Maidenhair Fern

Remove dry or scorched fronds as they appear. Cut damaged or dry fronds at the base with clean scissors. If the plant is severely degraded, all fronds can be cut back to the base — new growth will emerge if the roots are healthy and the substrate stays moist.

Through the year

Watering is not set once and for all: it follows the light and the growth. Allow 4 days between waterings in the depth of winter, against 2 in the growing season.

Active growth · Days between waterings

Good to know

The name Adiantum comes from the Greek adiantos meaning 'unwettable' — the ultra-fine leaflets of this fern are so hydrophobic that water beads on their surface without ever wetting them.
Maidenhair fern was used in traditional European medicine since the Middle Ages to prepare capillaire syrup, a remedy for coughs and sore throats that was very popular until the 19th century.

Frequently asked questions about the Maidenhair Fern

How do you care for a Maidenhair Fern?

Water it every 3 days. Give it medium light. Ideal humidity: 60–80 %. Ideal temperature: 15–25 °C. Keep the substrate constantly moist but never waterlogged. Never allow to dry out completely — even a single drying episode can kill the fronds. Water with water at room temperature, ideally non-calcareous.

How often should you water a Maidenhair Fern?

Every 3 days Keep the substrate constantly moist but never waterlogged. Never allow to dry out completely — even a single drying episode can kill the fronds. Water with water at room temperature, ideally non-calcareous. How to know it needs water : Top of substrate beginning to dry ; Fronds beginning to curl ; Leaflets becoming crispy and brittle.

How much light does a Maidenhair Fern need?

Medium light Moderate to diffused indirect light. Never expose to direct sun which instantly scorches the delicate fronds. Ideal in a bright bathroom or near a north-facing window. No direct sun

Is the Maidenhair Fern toxic to cats and dogs?

No, the Maidenhair Fern is not listed as toxic to cats and dogs. That is still no reason to let your pets chew on it.

Why are my Maidenhair Fern leaves turning yellow?

Yellowing most often comes from too much water: the mix stays wet and the roots suffocate. Check that the pot drains, empty the saucer, and let the mix dry before watering again. Too little light or a cold draught cause the same symptom.

When should you repot a Maidenhair Fern?

Repot every 18 months, ideally in spring. Use a plastic pot (retains moisture better than terracotta). Rich, humus-rich substrate: potting soil, peat, perlite, and a little sphagnum moss. Do not compact. Keep moist after repotting.