Staghorn fern care: mounting, watering and fronds

Light

Give it bright, indirect or filtered light. Clemson asks for exactly that, NC State lists dappled sunlight to partial shade, and Illinois Extension places the staghorn among plants needing at least medium light, about 150 foot-candles. A wall beside an east window is ideal, as is a spot near a west window behind a sheer curtain. Morning sun is fine; hot afternoon sun through glass bleaches and scorches the antler fronds.

Dim corners are a mistake. UF/IFAS notes that very low light encourages disease and pests, and a staghorn kept in shade grows slowly to begin with, producing thin, floppy antlers. If the fronds lean hard toward the window, move the board closer.

Water

Watering a mounted staghorn means soaking, not pouring. Take the board down and lay it, plant side up, in a sink or tub of room-temperature water for several minutes until the moss behind the shields is saturated, then let it drip dry before rehanging. Potted plants, NC State notes, can be watered from the bottom. Water again when the moss feels nearly dry and the board is noticeably lighter.

The sources disagree a little on how dry to let it get, and that is useful to know. Clemson says to keep the growing material moist at all times. NC State says to water the crown regularly and let the roots dry slightly between waterings without ever drying out completely. UF/IFAS, writing for outdoor plants in humid Florida, goes further and waits until the fern wilts slightly, because a wilted fern recovers quickly while an overwatered one rots and dies. Indoors, in dry air, the middle course works: soak, let the moss go from wet to barely damp, then soak again.

Seasons change the rhythm. UF/IFAS waters about once a week in warm, dry weather and less often when it is cool or cloudy. A board near a radiator in January can dry faster than one in a humid summer room, so judge by the moss and the weight of the board.

Soil and pH

A staghorn does not grow in soil. To mount one, UF/IFAS shapes a few handfuls of soaked sphagnum into a mound on a slab of untreated wood, bark or tree fern fiber, sets the fern so its shield fronds touch the moss, and ties it on. Their mounting guide prefers old pantyhose, which rots away instead of cutting into the plant; plastic strips or wire also work, but never copper. In a pot or a wire basket, NC State recommends an epiphytic orchid mix or sphagnum, with good drainage.

Humidity

Humidity is the hardest part indoors. Clemson states that staghorns need very high humidity that is difficult to achieve in most houses, which explains the crisp antler tips common in heated homes. A bright bathroom, a sunroom or a spot near a humidifier helps. Do not overdo it in a stuffy room, though: NC State warns that black spot can develop when humidity is too high, especially with little air movement.

Temperature

Clemson recommends day temperatures of 68 to 72°F (20 to 22°C) with nights of 50 to 55°F (10 to 13°C). P. bifurcatum is tougher than most of its genus: UF/IFAS says it can withstand temperatures as low as 30°F (about -1°C), while most staghorn species cannot take less than 55°F. That hardiness is for brief cold outdoors; indoors keep it above 50°F and away from cold glass and heating vents.

Fertilizer

UF/IFAS recommends a fertilizer with a 1:1:1 ratio, applied according to the label. Young plants get it monthly during warm months and every other month in cooler weather when growth slows. Mature staghorns need far less, once or twice a year. Skip feeding entirely on a plant that is struggling with rot or cold.

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

Repotting

Instead of repotting, a staghorn gets remounted. UF/IFAS says the time has come when the shield fronds have grown out to the edges of the mount. You can strap the whole plant, old board included, onto a larger board, or divide it. Some plants grow so large that remounting becomes impractical, and UF/IFAS points out that staghorns tolerate crowding, so there is no rush. Never peel the old brown shields away: they are part of the root system's protection.

• The shield fronds have grown out to the edges of the board
• Pups crowd the mount or push out of the basket
• The plant is too heavy for its hanger

Propagation

The rhizome hidden under the shields produces pups, small plantlets that form a colony over time. NC State and UF/IFAS both propagate by removing these pups or dividing a large plant. In the UF/IFAS mounting guide, a mature plant is cut into two with care to keep separate sets of shield fronds, some old roots are trimmed, and each part is tied onto soaked sphagnum on its own board or basket. Spores are another route, but division is the method NC State recommends.

Methods: Pups (plantlets) removed from the rhizome, Division of a large mounted plant · Best season: spring to summer.

Common problems

Two things alarm new owners and are perfectly normal: brown, papery shield fronds at the base, and brown felt on the undersides and tips of the antlers, which UF/IFAS identifies as sporangia. Real trouble starts with water. Soft, blackened shields and a rotting center mean overwatering, and black spots point to humidity that is too high with stagnant air. NC State lists spider mites, aphids, mealybugs and fern scale as pests. Leave the gray felt on the antler fronds alone when cleaning: it is part of the leaf, not dust.

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

Is the staghorn fern toxic to cats and dogs?

The ASPCA lists the common staghorn fern, Platycerium bifurcatum, as non-toxic to dogs, cats and horses, and NC State tags it as non-toxic and pet friendly. That makes it one of the safer statement plants for a home with animals. Mounting it on a wall also keeps it away from curious cats, which protects the fronds as much as the pet. As with any plant, eating a large amount can upset a pet's stomach, so call your veterinarian if an animal seems unwell after chewing it.

Check any other plant against the ASPCA lists →