Bird's nest fern care: watering, light and humidity

Light

Bright, indirect light suits it best. NC State suggests bright light or light shade such as a north-facing window, UF/IFAS EDIS recommends bright indirect light indoors, and Illinois Extension lists the bird's nest fern among plants needing at least medium light, about 150 foot-candles. Directly in front of a north window or a few feet back from an east window is about right.

Sun is the danger. UF/IFAS notes that in sunnier spots the fronds turn yellow and the plant stops growing, and NC State says the same. A west or south window is too strong unless the fern sits well back or behind a sheer curtain. Too little light is less dramatic: growth simply slows to a frond or two a season.

Water

This fern wants mix that stays moist without turning soggy. The UF/IFAS Nassau County office says it needs continually moist soil and should never go dry between waterings, Clemson says to keep the soil moist, and EDIS rates its drought tolerance as poor. Check the surface every few days and water before it dries, pouring slowly onto the mix around the edge of the pot until water runs from the drainage hole.

Aim at the soil, not the nest. New fronds unfurl from the tight center of the rosette, and a cup of water sitting there for days can rot that growing point or encourage the leaf diseases this fern is prone to. If water does collect in the center, tip the pot gently to pour it out. Bottom watering, standing the pot in a few inches of water until the surface darkens, avoids the issue completely.

Do not compensate by drowning the roots. Clemson warns that root rot in ferns usually comes from a mix that drains slowly or from watering too often, and that water should never stand in the pot. Moist and airy is the target, the way a fern perched on a branch would get frequent rain that drains straight away.

Soil and pH

NC State recommends a rich, moist, porous soil such as a fern potting mix, and EDIS lists high organic matter and acidic, occasionally wet soil among its tolerances. Clemson's fern blend of equal parts packaged houseplant mix and peat moss or leaf mold works well. Because this is an epiphyte, a little orchid bark or perlite in the mix keeps air around the roots.

Humidity

Humidity matters more in winter than in summer. NC State says a pebble tray may be needed to give it enough moisture in the air, and Illinois Extension notes that most homes drop below 30 percent humidity in winter. The Nassau County office suggests a bright, humid bathroom as an indoor home. Leathery fronds make it more forgiving than lacy ferns, but crisp edges on rippled cultivars are a sign the air is too dry.

Temperature

NC State gives ideal temperatures of 60 to 70°F (16 to 21°C), and Clemson's range for bird's nest ferns is 55 to 70°F (13 to 21°C). The hard limit is lower: NC State and the Nassau County office both say the plant will not survive or tolerate temperatures below 40°F (4°C), and it cannot take frost. NC State also warns against direct heat and drafts, so keep it clear of radiators, heating vents and doors that open onto winter air.

Fertilizer

Feed sparingly. NC State suggests a monthly application of dilute liquid fertilizer during periods of active growth, and Clemson's guidance for ferns is about half the label rate once a month from April through September, with nothing in winter. Ferns scorch when overfed. Clemson also suggests waiting six months before feeding a newly bought or repotted fern.

Work out the dose for your watering can with the fertilizer dilution calculator →

Repotting

Repot in spring, when new growth begins, and only once the plant has outgrown its pot; UF/IFAS gives that timing. Choose a container one size larger, with drainage holes, and keep the base of the rosette at the same level, never buried deeper. A heavy pot helps once the fronds spread wide. Because all the fronds rise from one central crown, this is not a fern you split into pieces at repotting.

• The rosette has outgrown the pot and tips it over
• Roots fill the pot and the mix dries out quickly
• Roots grow through the drainage holes

Propagation

Every frond of a bird's nest fern rises from one central crown, so division is not the usual route; new plants come from spores. They form in the brown lines arranged in a herringbone pattern under mature fronds, which NC State describes and UF/IFAS points out are not a problem. Growing ferns from spores takes patience and sterile, humid conditions, and most people buy a new plant instead.

Methods: Spores from the brown lines under mature fronds (slow; most growers buy plants) · Best season: any time, indoors under cover.

Common problems

Yellow fronds usually mean too much sun; brown, crisp edges mean dry air or a dried-out pot. Large dead patches are, according to the Nassau County office, probably fungal, and plants grown outside their preferred conditions are more prone to them. NC State lists slugs, snails, scale, mealybugs, bacterial leaf diseases and leaf nematodes, and warns that chemical insecticides damage the fronds, so remove pests by hand. UF/IFAS adds that insecticides typically harm ferns. Groom off old yellow or brown fronds occasionally.

Not sure which one it is? Try the plant problem diagnosis tool →

Is the bird's nest fern toxic to cats and dogs?

The ASPCA has no entry for Asplenium nidus on either its cats or its dogs list. NC State, which flags poisonous plants with a severity rating and warning tags, gives the bird's nest fern none, and the UF/IFAS pages mention no toxicity. The ASPCA does list a close relative in the same genus, Asplenium bulbiferum, the mother fern, as non-toxic to cats and dogs. That points toward low risk, yet a relative's listing is not a rating for this species, so this page marks the bird's nest fern as not rated rather than pet safe. Call your veterinarian if a pet eats a large amount and seems unwell.

Check any other plant against the ASPCA lists →