Caring for a fern

Gardening How-to Articles

Caring for Ferns as Houseplants

By Jeanne Rostaing | October 24, 2019

What is it about ferns that makes them so appealing? Although they don’t flower or produce fruit or heady fragrance, ferns are a go-to choice for many gardeners in the outdoor landscape, where they tend to be easy to grow.

But why bring them indoors, as many houseplant lovers do? Out in the yard they are nearly maintenance free. Inside it’s a different story. They are very particular about their needs and will up and die if neglected. Yet people continue to be besotted, pampering countless ferns on their windowsills, in their bathrooms and kitchens, and anywhere in the home that they feel could use the softening effect of some lacy fronds.

The Victorians really led the way in bringing ferns indoors. Their widespread obsession with collecting and exhibiting these plants was so prevalent and intense that it became known as pteridomania. Most people grew their specimens in urns or terrarium precursors known as Wardian cases, but ferns also flourished in the elaborate glassed-in conservatories of the rich. Reinforcing the fad were myriad images of ferns that appeared as motifs on textiles, pottery, and jewelry. Around the same time, enthusiastic hybridizers also created hundreds of new fern varieties, many of which are still popular today.

The fern madness of the Victorians eventually gave way to a fixation on orchids, but the tradition of growing ferns indoors has lingered, and a multitude of varieties for that purpose continues to exist. Seemingly, there is a fern you can grow as a houseplant anyplace you can think of except, perhaps, the inside of a closet or under the bed.

Caring for Ferns

Ferns have a reputation for fussiness, and their cultivation requirements are quite specific. Still, with a little thought and attention, you can successfully grow and maintain them as houseplants. Experts advise analyzing your conditions carefully and then selecting a species that is well suited for the location you have in mind.

In general, for maximum growth and health, it is important to provide ferns with plenty of humidity, generous watering, lots of space, sufficient light without direct sun exposure, and rich, well-draining soil.

Moisture

Proper humidity can be one of the most difficult conditions to provide since most of us who live in temperate climates have central heat, which is very drying. Home moisture levels can be desertlike, as low as 5 to 10 percent relative humidity, well below the 40–50 percent levels recommended for ferns.

There are a few simple methods for countering that dryness. Daily watering will help. Resting potted ferns on water-filled saucers or trays that contain a layer of pebbles or broken crockery is another simple way of keeping the humidity high. Just make sure that the bottoms of the pots rest above the water, not in it. Soggy fern roots can lead to rot and untimely death. Another trick is to place ferns planted in clay pots inside a larger plastic pot lined with a damp, spongey medium such as peat moss. The clay pot will wick the moisture from the peat moss and help prevent the fern soil from drying out.

To grow ferns indoors, try to replicate the moist, low-light conditions where the thrive outdoors. Photo by Blanca Begert.

If more moisture is needed, the use of a humidifier near your plants is an option. Drugstore humidifiers are designed to hydrate people, not plants, so there are a few special features to look for when purchasing one. Generous run time is important—select one that can run continuously without refilling for at least 12 hours. Humidifiers have to be cleaned frequently to keep them from spewing salt, mold, or bacteria on your plants, so choose one with a simple design to streamline the chore.

You probably see fern fronds, or leaves, used as fillers in flower arrangements. But don’t let that make you think fern plants will tolerate being packed tightly against a begonia or peace lily in your home. Their delicate leaves are easily broken and they need plenty of freely circulating moist air to prevent damage and keep them sufficiently hydrated. This is an important point to remember if you decide to use a humidifier. Placing a fan nearby will help disperse the moisture-laden air and keep water droplets from landing on your plants, possibly causing blights and other distressing fern diseases.

Light

The issue of light for the indoor fern is fraught for many gardeners. I prefer not to know how many ferns I have killed simply because I thought the plant was the perfect answer to livening up a dark corner. Although ferns are happy residents of shade gardens outdoors, inside they require plenty of bright, indirect light. Exposure to direct sun will burn their delicate foliage, making it dry and brittle and browning the edges. Avoid southern exposure where ferns will be subjected to harsh solar rays.

Soil Mix and Containers

When planting your ferns, choose a light, fluffy soil mix that contains plenty of organic matter, but not enough to make the soil so heavy and dense that it does not drain well. Most packaged houseplant mediums should work well as long as they are rich in porous organic materials such as peat moss or leaf mold. Adding coarse sand or perlite will allow water to flow through freely.

Both plastic and clay pots are suitable for ferns, with those in plastic pots requiring less frequent watering. Pots should be large enough to accommodate the roots with an extra inch of space for further growth. Fern roots tend to be shallow, so short containers are best. Most ferns grow slowly but you should repot when they begin to overcrowd their containers, before they become root bound.

Choosing a Fern

Ferns are known to be one of the oldest groups of living things on earth, dating back more than 300 million years. Today’s ferns, the descendants of those ancient plants, include more than 10,000 living species, second only to angiosperms or flowering plants. With so many ferns to choose from, selecting the right one can be daunting. Below are some good species to start with, and all tend to be widely available.

Caterpillar Fern (Polypodium formosanum)

Also called the grub fern, this species gets both common names from its blue-tinged rhizomes that resemble the insects and grow on top of the soil and over the side of the pot. While this plant requires the specific growing conditions discussed above, it is popular with home gardeners because it can survive the neglect of insufficient watering better than most. The fronds may turn brown and the distinctive rhizomes shrivel but they can recover once proper moisture is restored.

Lacy Rabbit’s Foot Fern (Davallia fejeensis)

This fern is similar in form to the caterpillar fern with furry, animallike rhizomes that are above ground. Both varieties are shown off to excellent advantage in hanging pots. Rabbit’s foot fern also has a reputation for toughness and, like the caterpillar fern, can survive a certain amount of neglect.

Bird’s Nest Fern (Asplenium nidus)

This fern is an epiphyte in its native rainforest habitat, which means it grows on another plant instead of in the ground. It is quite handsome in a very un-fernlike way, with unusual straplike fronds that emerge from a dark crown or “bird’s nest.” Grown in a pot indoors, this plant will tolerate occasional lapses in watering and somewhat less humidity than other ferns.

Japanese Holly Fern (Cyrtomium falcatum)

A vigorous plant with shiny, spiky leaflets that resemble holly foliage, Japanese holly fern is hardy to USDA Zones 6 to 11 where it can be grown outdoors as a shade plant. Inside it is more forgiving than other ferns, tolerating less humidity, brighter light and cooler temperatures. It is also larger than many ferns, typically reaching 2 feet in height and 3 feet in width.

Button Fern (Pellaea rotundifoli)

A small plant with delicate, rounded leaflets, button fern has a low-growing horizontal habit and typically only reaches about a foot in height. This plant is particularly insistent on plenty of humidity and should never be allowed to dry out.

Whatever fern you choose, be sure to commit yourself to its care requirements and prepare to enjoy its beauty for years to come. If you decide to propagate your fern, you will have a number of options depending on what type of fern it is. The simplest method is division and works with most ferns except the bird’s nest type. Some ferns produce tiny versions of themselves, bulbils, that can be collected and planted.

Other ferns, which spread via under- or above ground stems called rhizomes, can be propagated by cutting off and planting a piece of the rhizome. Ferns produce spores rather than seeds, and spores can be harvested from their growing location on the underside of fronds and planted.

By successfully cultivating ferns you can congratulate yourself on helping to preserve a genus whose ancestors helped to sustain the dinosaurs and predated the arrival of more conventional garden plants by millennia.

Jeanne Rostaing contributed to BBG’s Japanese-Style Gardens handbook and writes frequently for Gardenista.

Read on for our top tips for helping your indoor ferns to thrive…

Customers in our shops are often asking the best way to care for their newly purchased plants and regaling stories of previous unexplained plant disasters, so we’ll be putting together some quick reference plant guides over the coming weeks to help those who want to get a little more green-fingered!

Rest assured, our succulent obsession and cactus love affair is by no means over, but we have made some room in our hearts for ferns! Some unusual types of ferns are gaining popularity as house plants thanks to their interesting and delicate shapes and textures. In general, indoor ferns like a medium-bright spot which receives no direct sunlight, and a more humid environment rather than somewhere cold and drafty (as is a common condition of many UK homes!). However, each species differs slightly in where and how they thrive, so we’ve put together some easy to follow fern-care tips.

A great investment if you are looking to bring ferns into your home is a mister. If you visit one of the Botanique Workshop London shops you’ll find a beautiful brass mister (which is an object of beauty in itself) for £14 – they also make the perfect gift for a plant loving friend.

Asparagus fern

This is very light and delicate-looking plant, and would look wonderful in a more minimalist interior as it evokes thoughts of a Japanese zen garden. Humidity is very much appreciated by these ornate plants and if you’re in the UK or the Northern Hemisphere you’ll find that your inside environments can get quite dry, especially over winter thanks to central heating. This is where misters come into their own.
As delicate as the Asparagus Fern looks, it’s actually more tolerant than some other indoor fern types. It also responds well to pruning or trimming, so you can help coax your plant into the shape or form you like – just imagine you are doing your own version of zen gardening!

Location: Bright, but indirect, light. If it’s in a sunnier room (but out of direct light) it will grow faster than in a darker space.

Watering: Mist often. Water, but allow the soil to dry out a little between watering.

Warning signs: If the plant is receiving too much sun, the tiny leaves (or needles as they are also known) will become yellow and fall off.

Size: Can grow up to 90cm tall

Maidenhair fern

A feathery fern with leaves as light as air, this houseplant can be a little more tricky to keep healthy and happy. The main culprit of demise for this fern variety is direct sun – even if it will only be in the sun for an hour or two a day the leaves will shrivel away to nothing quite quickly, so although it likes a light room keep away from the sun’s direct rays!

Location: Indirect sunlight ONLY. Keep out of direct sunlight.

Watering: It requires moisture constantly. The best way to provide this is keeping it in a humid bathroom or conservatory, or using a mister to mist the leaves with water.

Size: Can grow up to 60cm tall.

Boston fern

Boston Ferns may be what a lot of people imagine as a ‘typical’ fern. They are popular houseplants and like most of the other ferns, these guys love being kept in a humid environment – pictured here is the beautiful brass mister we sell in our two London stores for £14.

Location: They like indirect light so keep them out of strong sun rays in a light room.

Watering: Make sure that the soil is always damp and does not dry out because this is the main cause of death for these moisture-loving houseplants.

Warning signs: If the Boston Fern isn’t getting enough water – both through the soil and air, it may appear dull and lifeless. This is the warning to give it a good water and spritz!

Size: It can grow long frilly fronds which look amazing hanging out of a hanging basket. If any fronds become discoloured or unattractive, simply trim with clean sharp scissors or a knife at the base of the frond. This fern will grow quite large is repotted and given the ideal conditions.

Silver Brake Fern

Not a fan of the typical fern shape? You might be drawn to the quirky leaves of this particular variety. The unique leaf shapes can add texture to an interior even if you’ve just got a small plant, or they can create a real focal point once the fern has grown to full size.

Location: An unusual type of fern, this variety actually likes a medium to bright room (though as with the others, direct sunlight is a no-no).

Watering: Loves high humidity, so again, steamy bathrooms or regular misting are the tip tips.

Size: Grows up to 60cm tall.

Rabbit’s Foot Fern

Great in an indoor hanging pot. At Botanique Workshop stores we stock handcrafted ceramic hanging posts made by Lazy Glaze which are the perfect textural and neutrally coloured background to compliment these lush plants.

Location: A medium to brightly lit area out of direct sunlight.

Watering: In summer keep the soil moist, but don’t let it get water-logged. In winter you can let the top layer of soil dry out a little between waters.

Size: Can grow to around 45-60cm tall.

Love greenery but can’t commit to keeping a living plant?

Whether you are planning to move overseas, or would just prefer some commitment-free greenery you can never kill, our handmade real pressed leaf glass frames might be just what you’re looking for! We’ve preserved the beauty of flowers and foliage between two layers of glass which have then been skillfully soldered together in our London Workshop.

Made to order, these frames are each one of a kind and so would be a unique addition to your home. Browse the various options here. We even ship worldwide, and think one of the mini sizes would make such a sweet gift to a far-away friend.

Although all the ferns we’ve talked about all have their own preferences, just remember in general they seem to like medium-bright spaces, to be kept OUT of direct sunlight, and to be kept moist with a mister but don’t make the soil soggy! Humid bathrooms are the happiest hang out for most ferns.

At Botanique Workshop we have an ever-changing and extremely varied collection of houseplants at both our London Shops located on Exmouth market in Clerkenwell, and on Church Street in Stoke Newington. Come and find the right plant to you in our urban jungles and start your own collection!

Sign up to our newsletter to receive more plant care tips, and news about the latest hand-crafted additions to both our London stores and the Botanique Workshop website. Just scroll down to the bottom of the page and enter your email address in the box provided.

The Friends of the Wild Flower Garden, Inc.

Shape: Christmas Fern is an evergreen fern growing in circular arching clumps.

Fronds: They are dimorphic, that is the fronds are either sterile or fertile. Fronds are pinnate and do not have the pinnae divided into individual pinnules. Fronds have from 20 to 40 pairs of pinnae, the two lowest often point downward away from the blade plane. The lower pinnae appear opposite but from the middle of the frond upward they appear alternate. Sterile fronds and the non-fertile part of fertile fronds remain evergreen over winter, but usually flattened by snow load. The rachis is green and scaly. The stipes are grooved and scaly, with 5 vascular bundles. Stipe length is 1/4 to 1/3 the length of the blade.

Sterile fronds are once pinnate, arching, paler color beneath with hair-like scales. Above they are darker green and scaleless, also shorter and less erect than the fertile fronds.

Fertile fronds have both sterile and fertile pinnae. The upper pinnae are fertile and are much smaller then the sterile pinnae lower on the frond.

Pinnae: On all pinnae an auricle (lobe) at the upper side of the base points upward to the tip of the blade. The margins of sterile pinna have spiny tipped teeth that curve upward. Veins in the pinnae are forked and extend to the margin of the pinnae. Overall, the mature pinnae give the fronds a leathery dark green appearance.

Fertility: Sori are oblong, green initially then tan colored, covered with a circular indusia and in two or more rows on either side of the mid-rib on the reduced pinnae that form the upper 1/3 of the fertile frond. Indusia are thick, entire and blackish when dry. Since the upper pinnae are quite small, the entire underside seems to be covered.

Fiddleheads are scaly and stout with silvery white scales, appearing among the recumbent green fronds of the prior year.

Habitat: Growth is from a large compact scaly creeping rhizome that is long-lived. It prefers moist well-drained rich soil, neutral to acidic. They tolerate shade well, but if in a lot of sun, the soil must be moist. Soil in winter should remain dry. Clumps can be divided in spring or fall. Christmas Fern is a good fern for beginners in fern culture.

Names: The common name comes from the use of this evergreen fern for decoration during the Christmas time. The genus, Polystichum, is derived from the Greek Words polys, meaning ‘many, and stichos, meaning ‘row’ and together referring to the rows of sori on the type species for this genus. The species name, acrostichoides, is a reference to the genus Acrostichum where the sori form a solid mass on the back of the pinnae of the fertile frond – as they do here.

The author names for the plant classification are as follows: First to publish was ‘Michx.’ which refers to Andre Michaux (1746-1802), French botanist who made many exploring expeditions in the U.S. collecting and cataloging many species. Two important works of his are the Histoire des chênes de l’Amérique septentrionale (1801 – Oaks of North America), and the Flora Boreali-Americana (2 vols., 1803). His son Francois, traveled with him and the father’s notes were later used for the 3-volume North American Sylva, for which Thomas Nuttall provided some supplements. Michaux’s work was amended by ‘Schott’ who is Heinrich Wilhelm Schott (1794-1865), Austrian botanist who did extensive work on the Araceae family. His last position was director of the Imperial Gardens at Schönbrunn Palace in Vienna.

Scientific name: Polystichum acrostichoides
Common name: Christmas fern

(Information in this species page was compiled in part by Jon Belasco as part of the Biology 220W class at Penn State New Kensington in Spring 2001)

Appearance
Polystichum acrostichoides is called the “Christmas fern” because some parts of the plant remain green throughout the year and are thus available for use in decorations at Christmas time. The rich, green leaves (fronds) of the fern are up to three feet long and are about four inches wide. They are tough, leathery and lance-shaped to a pointed tip. The fronds are attached to a relatively short stalk that is brown at its soil base and green toward its apex. A central, perennial root (the rhizome) supports the stalk that then supports the arching clump of tall fronds. The sterile fronds (fronds not involved in reproduction) are shorter and less well supported than the spore producing fertile fronds. The sterile fronds, then, form an encircling, arching border around the central mass of taller, more erectly held fertile fronds. It is the sterile fronds which remain green throughout the year.

Each fertile frond sports 20-40 leaflets, with the sori (clusters of spore-producing sporangia) forming only on the upper third to half of the leaflets. These fertile leaflets are noticeably shorter than the non-sori bearing leaflets, giving the impression of a sudden narrowing of the entire fertile frond toward the top.

Reproduction
In a typical fern life cycle, spores are produced within sporangia when moisture and temperature conditions are favorable. In the Christmas fern, spore production occurs between June and October. A small percentage of the released spores from the tall, erectly held fertile fronds will find an optimal microhabitat in the surrounding soil and then be able to grow into the fern’s tiny sperm and ova producing life stage called the gametophyte. Fusion of the sperm and ova within the gametophyte will produce a new sporophyte which can then grow into a mature fern.

New sporophytes can also arise vegetatively from the perennial rhizome. These coiled young ferns are called fiddleheads (see image at right). Fiddleheads arise in the early to mid-spring.
Habitat
Christmas fern is found in the north-eastern and north-central portions of North America from New Brunswick south to North Carolina. It is especially abundant on well shaded, forested hill sides near streams. Soils of moderate moisture and a more neutral pH are preferred. This pH preference is reflected in the increased densities of Christmas ferns in soils that overlie limestone bedrock. Christmas fern is seldom found in soils that are too waterlogged or that are too rocky.

Ecological Significance
Christmas fern may grow in large, extensive colonial masses but more typically is found in clusters of two or three individuals. Growing ferns and the accumulated detritus of past sterile fronds form a dense covering mass over the soil surface. This mass helps to stabilize the underlying soil and prevent or lessen erosion. It also generates a protective, concealing habitat for a number of ground feeding and ground nesting bird species.
Because of their complex chemical composition, ferns are eaten by very few browsers or grazers. Fern densities in general have been increasing in many of the forests of Pennsylvania due to the removal of competing, but more palatable, under-story plant species by the extensive browsing by the state’s rapidly increasing deer population. This change in the forest under-story habitat structure has had wide-spread and deleterious impacts on the densities and successes of some mid-canopy birds (like the least flycatcher and the yellow billed cuckoo). Other bird species (like the wild turkey, for example) that use the concealing fern masses for their nesting sites have, however, increased in density in these “fern park” forests.
In commercially grown Christmas ferns a fern scale insect and the mealy bug can extensively feed on and damage the plants. Also, the larvae of the pyralid moth (Herperogramma aeglealis) can construct a variety of feeding shelters within the sterile fronds of the Christmas fern and consume its terminal frond leaflets (probably before they accumulate significant levels of their protective chemicals).

There is little mystery about how the Christmas fern got its name. Its timing was right; it is green when much of the natural world is brown, absent or dormant. There is, however, a more subtle reminder of the holiday season to find among its fronds. Each of the pinnae — the individual leaflets of any fern — is shaped like a little Christmas stocking, and with a bit of imagination, you can picture the little feet marching up the fern’s central stem, or rachis.

Those features attracted the attention of early settlers, who found the plant fairly abundant in the Northeastern woods. It may be apocryphal, but there is an old chestnut that tells of early settlers’ using it to decorate their Christmases. In the spirit of the holidays, I like to think that the colonists’ very real deprivations were assuaged, at least in part, by the beauty of small things like the fern.

But I have never seen a fern frond wreath, and it is worth noting that though the Christmas fern remains green in winter, it is not the arching, handsome plant you see in spring and summer. In late fall and winter, the Christmas fern’s fronds lie flat on the ground, allowing it to duck out of winter’s worst weather. Snow is an excellent insulator, and the temperature is rarely much below freezing under a blanket of just a few inches. The fern’s prostrate winter look, and its near invisibility under snow, probably explain why white pines, hollies and firs won the upper hand in the New World’s Christmas convention.

But every fern leads an ancient, double life, and the Christmas fern is no exception. It has an alter ego, rarely seen. The spores produced by the feathery adult fern mature into a heart-shaped plant mere millimeters tall. When water collects on this gametophyte, it releases amorous, mobile sperm cells that swim across the heart’s surface to fertilize the plant’s ovules, or eggs.

Leave a Reply

Your email address will not be published. Required fields are marked *