Hymenophyllum dimidiatum

filmy fern

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Taxonomy

Common Names

filmy fern

Context

nativeRegion

Southeast Asia, East Asia, and Oceania—often in moist forest habitats.

usdaZones

10–12 (grown as houseplant outside its range).

companionPlants

Other filmy ferns, Mosses, Selaginella species

culturalUses

Mainly ornamental; valued for its intricate fronds in botanical collections and specialty fernariums.

Care

LightPrefers bright, indirect light or filtered shade; avoid direct sun to prevent leaf scorch.

WateringKeep soil consistently moist but not waterlogged; does not tolerate drying out.

SoilRequires loose, humus-rich, acidic substrate with good drainage; ideal in sphagnum moss mixes or on bark.

FertilizerApply a diluted balanced fertilizer sparingly during the growing season; sensitive to over-fertilization.

HumidityVery high humidity needed (70%+); thrives best in terrariums or greenhouses.

TemperatureOptimal temperatures are 12–25°C (54–77°F); avoid frost and cold drafts.

HabitDelicate, epiphytic or lithophytic fern with thin, translucent fronds.

Mature SizeTypically up to 10–20 cm (4–8 inches) in frond length.

Growth RateSlow to moderate growth rate.

BloomingNon-flowering (produces spores, not flowers).

DormancyEvergreen but may enter reduced growth in dry or cold periods.

MethodsSpore sowing, Division of rhizomes

DifficultyChallenging due to tiny spores and moisture needs.

Best SeasonSpring to early summer

PruningRemove old or brown fronds regularly to encourage new growth.

RepottingRepot every 2–3 years or when root-bound, ideally during active growth.

Pests & DiseasesSusceptible to snails, slugs, and fungus gnats; fungal issues may arise if overwatered.

ToxicityNon-toxic to pets and humans.

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