Maidenhair fern
Sources last read 14 September 2026.
Difficult One of the harder ones, and one of the reasons the diagnosis tool exists.
Also called Delta Maidenhair, Pacific Maidenhair and roseate maidenhair fern.
Toxicity is partly unassessed
- Not assessed for cats. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
- Not assessed for dogs. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
- Not assessed for people. RHS publishes no harm statement for this plant. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
What the sources say about its care
- Light
- Partial shadeRHS · read 11 September 2026
- Water
- Moist but well-drainedRHS · read 11 September 2026
- Humidity
No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.
ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%Penn State Extension · read 11 September 2026- Temperature
How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.
H1C — 5–10°C 5–10 °CRHS · read 11 September 2026- Soil
- Loam; pH Alkaline or NeutralRHS · read 11 September 2026
- Toxic to cats
- Not on the ASPCA list. That is not a finding of safety.ASPCA · read 11 September 2026
- Toxic to dogs
- Not on the ASPCA list. That is not a finding of safety.ASPCA · read 11 September 2026
- Harmful to people
- No harm statement is published for this plant; that absence is not evidence it is safe.RHS · read 11 September 2026
How it usually goes wrong
- Brown tips on the newest fronds first
Fronds on the side of the maidenhair fern nearest a heater or vent brown at the edges while those on the far side stay clean.
Dry air takes water from the leaf surface continuously, and the tissue at the edge is last in the queue for what the roots send up. Penn State Extension notes there is no single humidity figure that suits every indoor plant.
Telling it apart: Whether the damage advances. Dry air marks a leaf and stops; rot keeps going.
Penn State ExtensionMaidenhair fern brown leaf tips and edges: causes- Lower fronds collapse and yellow within days of a watering
Colour goes before shape on a maidenhair fern. The lowest fronds yellow evenly, stay soft to the touch, and the compost two inches down is still wet from the last watering.
The source for this plant describes moist but well-drained soil. Compost that stays saturated loses the air spaces fine roots grow into, and those roots die back first.
Telling it apart: Weigh the pot in your hand. A pot still heavy a week after watering is holding more water than the roots are using.
RHSMaidenhair fern leaves turning yellow: causes- New fronds arrive smaller and paler than the ones below
Growth on the side of the maidenhair fern away from the light slows or stops, so the plant becomes lopsided over a few months.
Light is the budget every other process is paid from. Under the partial shade its source names, the plant spends down reserves and shows it in thin, pale growth.
Telling it apart: What the newest growth looks like beside the oldest. Light changes what arrives next; feeding changes what is already on the plant.
RHSMaidenhair fern leaves turning yellow: causes
Not sure which it is? Ask the diagnosis questions for Maidenhair fern.
Routine care
- Watering
- The genus name derives from the Greek adiantos, "unwetted", referring to the leaves that shed water.NC State Extension · read 13 September 2026Between mid spring and late summer, water generously and feed monthly with a general liquid feed at half strength. Give little water in winter.RHS · read 13 September 2026
- Feeding
- Between mid spring and late summer, water generously and give a general liquid feed at half strength each month.RHS · read 13 September 2026
- Propagation
- By division.NC State Extension · read 13 September 2026Sow spores once ripe at 21°C or warmer, or divide the rhizomes in early spring.RHS · read 13 September 2026
- Pruning
- Needs little pruning beyond removing dead leaves.RHS · read 13 September 2026
- Pests and diseases
- Can be troubled by mealybugs, soft scale and Florida fern caterpillar. Other problems: sunburn.NC State Extension · read 13 September 2026Scale insects can attack it. Disease is uncommon.RHS · read 13 September 2026
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Photographs
About the plant
Adiantum raddianum, the Delta maidenhair fern, is one of the most popular ferns to grow indoors. It is native to South America and its common name comes from its shiny, dark leafstalks that resemble human hair. It typically grows about 17–19 in (43–48 cm) tall and up to 22 in (56 cm) wide. In the wild, it is found on forest floors, rock crevices, river banks, coastal cliffs, and basalt banks along trails and streams. The triangular fronds are semi-erect in the beginning then droop gracefully as they age and can be up to 12 inches (30 cm) long by 6 inches (15 cm) wide. The genus name Adiantum comes from the Greek word "adiantos", meaning "unwetted".
From Wikipedia, CC BY-SA 4.0 · read 13 September 2026
- Native range
- Mexico to Trop. AmericaWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026Tropical Americas and West IndiesNC State Extension · read 13 September 2026Tropical America: W IndiesRHS · read 13 September 2026
- Climate
- wet tropicalWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026
- Growth form
- perennial or lithophyteWorld Checklist of Vascular Plants, June 2026 release, CC BY.Kew WCVP · read 13 September 2026Fern; habit arching, clumping, creepingNC State Extension · read 13 September 2026Clump forming, Bushy (evergreen)RHS · read 13 September 2026
- Size
- Height 12–24 in; width 12–24 inNC State Extension · read 13 September 2026Height 0.1-0.5 metres; spread 0.1-0.5 metres after 2–5 yearsRHS · read 13 September 2026
- Flowering
- No flowers.NC State Extension · read 13 September 2026
Common problems with Maidenhair fern
Other Adiantum
More of the Pteridaceae family
Plants with similar care
Sources
- ASPCA · read 11 September 2026
- Kew WCVP · read 13 September 2026
- NC State Extension · read 13 September 2026
- Penn State Extension · read 11 September 2026
- RHS · read 13 September 2026
- Wikipedia · read 13 September 2026
What this does not cover
The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.
Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.
If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.