How to Plant, Grow, and care for Boston Ferns

The lush, green fronds of the Boston fern can bring color to your home, inside and out. These iconic ferns are perfect for hanging baskets, cascading over the rim, and giving the space an abundant tropical look. Learn all about them with Lorin Nielsen's growing guide.

A close-up shot of the Boston fern perennial

Contents

Did you know that the Boston fern can reduce pollutants in the air? Well, every plant can, but the Boston fern is one of the highest-rated species to do so. It’s also beautiful when grown in pots or in hanging baskets. It can really brighten up the house with its vibrant green or greenish-yellow foliage. And the boston fern is easy to care for, too!

Does this make you want to grow your own Boston fern? Well, whether you’ve got a hanging basket in your window or cultivating a bed along the shaded side of your home, I’ll tell you everything you need to know!

Plant Overview

A shot of a Nephrolepis exaltata plant placed in a grey pot in a well lit area
Plant Type Fern
Family Nephrolepidaceae
Genus Nephrolepis
Species Nephrolepis exaltata
Native Area Southern USA, Caribbean, Central America, North and Central South America
Exposure Partial shade, Indirect bright light
Height 12-24”
Watering Requirements Moderate
Pests & Diseases Nematodes, caterpillars, fungus gnats, mealybugs, thrips, scale insects, fungal diseases
Maintenance Low
Soil Type Well-draining, rich loam
Hardiness Zone 9-11

What Is The Boston Fern?

Nephrolepis exaltata is the botanical name for the tropical plant Boston fern. In 1894, a cultivar of this fern was discovered in a shipment from a Philadelphia grower to a Boston distributor and named it Nephrolepis exaltata ‘Bostoniensis’, hence the name Boston fern. These are angiosperms – or spore producers. These ferns are true ferns that enjoy understory areas with consistently moist soil.

Native Area

A shot of a perennial showcasing its lush green leaves that is all placed in a well lit area outdoors
These perennials are native to North and Central South America, Central America and the Caribbean.

Nephrolepis exaltata is native to tropical regions of forests and wetlands of north and central South America, Central America, the southern coastal regions of the US, and some islands in the Caribbean.

Characteristics

A close-up shot of a perennial showcasing its lush green arching fronds in a well lit area outdoors
It has lush and arching fronds.

Nephrolepis exaltata is a popular houseplant and garden fern with lush, arching fronds that grow in a rosette pattern. This evergreen fern thrives in humid environments and is admired for its delicate, feathery leaves, which give it a soft, cascading appearance ideal for hanging baskets or as a ground cover in shaded areas.

It is particularly effective at purifying indoor air, filtering out toxins like formaldehyde. The Boston fern does well with high humidity and regular misting, but it can be sensitive to changes in temperature and humidity, making it important to keep it in a stable, moist environment to prevent the fronds from browning.

With the right care, this fern can become a lush and beautiful addition to both indoor and outdoor spaces.

Planting

A close-up shot of a person wearing a black shirt holding a Nephrolepis exaltata that is placed in a pot in an area indoors
Select a well-draining potting mix that retains moisture.

To plant Nephrolepis exaltata, choose a well-draining potting mix rich in organic matter, ideally a peat-based soil blend that retains moisture but doesn’t become soggy. Select a pot with good drainage, as the fern’s roots are sensitive to standing water.

Start by filling the pot about halfway with soil, then place the fern in the center, gently spreading out its roots. Fill in around the roots with soil, pressing lightly to secure the plant, and water it thoroughly until water drains from the bottom.

How to Grow

Whether indoors or outside, learning the tenets of Boston fern care is simple as long as you follow our tips!

Light

A shot of a plant that is placed indoors that is basking in the bright sunlight with a white wall background
The light requirements will vary, depending on the season.

Light requirements vary depending on the season. In the fall and winter, they benefit from bright indirect light. In English, that means about five feet away from a south-facing window. A Boston fern loves lots of indirect light.

It’s the more powerful light levels spring and summer which becomes difficult for the Boston fern. They can’t tolerate direct sunlight for long and need to be placed in a location with filtered sunlight. Generally, northern-facing windows which get indirect light are good, as are shaded places under trees. If your home provides sun shelter, that’s also great.

Don’t think that the Boston fern doesn’t need light at all. It requires a minimum of two hours of indirect light a day.

Water

A shot of a person wearing a light-brown apron and holding watering can to pour water to a potted perennial in an area indoors
Watering will depend on where you are growing the perennial.

How often do you water a Boston fern? Well, that depends on their environment. If you’re growing it as an indoor plant, you should start watering once the top inch or so of soil is dry. Water at the soil level to keep the fronds dry.

If your Boston fern prefers more humidity, you can place a tray with stones and water in it beneath the pot. This will keep your ferns lush and happy. If your Boston fern is in a hanging pot, give it a light misting with a mister bottle occasionally.

If your fern is grown outdoors, you ideally want to water when the top inch of soil is dry. However, in warmer months, this is more difficult, and they want high humidity levels. I recommend mulching around the base of your plants to help keep the soil a bit moist and provide a warm and humid environment. You don’t want it soggy, but you also don’t want it bone-dry!

One interesting fact about the Boston fern is that very cold water can shock its roots. Try to leave your water in a bucket or watering can for a little while so it can warm up if it’s cold.

Soil

Close-up of a gardener's hand holding a garden trowel with peat moss organic matter on a table in a sunny garden.
The plants will develop well in a rich, well-draining soil blend.

As ferns often live in tropical environments, they do appreciate a rich soil blend. However, they don’t necessarily need one. A mixture of peat moss, sand, and good potting soil can provide the good drainage that the Boston fern needs while still holding enough water to keep the soil moist.

If you have compost at hand, blend a little of that into your peat moss soil mix as well. Ferns (especially potted ferns) do appreciate soil that’s rich with plant matter.

Temperature

A focused shot of a perennial showcasing its lush green arching fronds, placed in a white pot in a well lit area outdoors
The plant thrive warm and humid environments, with temperatures between 65°F and 75°F.

Boston ferns prefer a warm and humid environment, thriving best in temperatures between 65°F and 75°F (18-24°C). It can tolerate slightly cooler temperatures, down to around 50°F (10°C), but prolonged exposure to cold can stunt its growth and cause frond damage.

Avoid placing the fern in areas where temperatures fluctuate significantly, such as near drafty windows, air conditioners, or heating vents, as sudden temperature changes can stress the plant and lead to browning fronds.

During colder months, it’s essential to keep the plant away from frost, as freezing temperatures are detrimental to its health. In warmer, humid climates, Boston ferns can also grow outdoors in shaded, protected areas. With stable, moderate temperatures and adequate humidity, Nephrolepis exaltata will maintain its lush, green appearance year-round.

Fertilizer

A close-up shot of a person wearing a light-khaki shirt holding a bottle of liquid fertilizer, pouring it into a smaller container
Use organic liquid fertilizers, or diluted commercial liquid fertilizers.

Use liquid formula for your Boston fern. You can opt for an organic such as liquid kelp, or you can choose a commercial houseplant fertilizer that’s diluted to half its normal strength. Fertilizer should be applied at the base of the Boston fern so as to not scorch its fronds.

Maintenance

A shot of a person's hand inspecting leaves of a perennial in a well lit area indoors
This plant is fairly low-maintenance, so occasional pruning will do.

There is very little maintenance on a Boston fern, but occasionally, give it a good look to see if it needs repotting or pruning. This will also be a watchful eye to spot any pests and diseases requiring instant attention.

Repotting

Repot the perennial to help it can grow larger.

If you are starting a runner in a new pot or replanting a cutting from an older Boston fern plant, be sure to use sterile, well-draining potting mix. This will help your new plant to take off without any crowding from weed seeds that might be in older soil.

Generally, you don’t have to repot a Boston fern unless you want it to grow larger. The roots fill the pot over time and eventually will get too crowded. At that point, it’s good to divide your Boston fern every few years to allow it to develop new roots.

Pruning

A shot of a person wearing a light-brown apron repotting a perennial in an area indoors
The plant doesn’t require much pruning aside from removal of older leaves to promote new leaf growth.

The Boston fern doesn’t require much pruning. Older leaves can be snipped off at the base of the plant to allow for new leaf growth. This also helps to remove leaves that may be browning or otherwise worse for wear. Generally, pruning Boston ferns is more of an aesthetic matter than one of plant maintenance.

Propagation

A focused shot of a leaf of a perennial with visible spores that is situated in a well lit area outdoors
These plants can propagate through spores, its stolon and through dividing the perennial.

Propagating a fern takes one of two forms: runners, or division. While fern spores are viable, they’re difficult to grow new plants from.

Runners will extend out from a large Boston fern and will gradually develop roots. These runners are called stolons. You can remove these at the base of the old plant and repot them in sterile potting soil. They will develop a new Boston fern from the stolon.

Alternately, you can divide a Boston fern. To do this, wait until the soil becomes dry more than you normally would. This will allow the root system to dry out a bit too. Remove the Boston fern from its pot or carefully dig it up from the soil. Then, use a serrated knife to cut the fern’s root ball in half. You can cut it in quarters or eighths from there if you wish more plants to form. Repot the new Boston fern plants, keeping them moist but not wet.

Common Problems

While the Boston fern care is surprisingly simple, there is a short list of things which can affect it negatively. Here’s what might occur, and how to fix it if it does.

Growing Problems

A focused shot of a wild plant growing outdoors on a moist trunk in a well lit area.
Common issues are caused by drought, insufficient light and poor water quality.

The most common problem that occurs in the process of Boston fern care is when it appears greyish in color. If the leaves appear to be greying, and the plant’s growth appears to have stalled, it is likely the result of drought conditions. Be sure to regularly water your Boston fern once the top layer of soil has dried out.

If the fronds of your plant seem to be weak and droopy, it may require more light. Move it to a location where it gets a minimum of two hours of indirect bright light per day.

While leaves are generally a deep green hue, a lighter coloration can be caused by too much direct sunlight. If you’re trying to cultivate a dark green fern, be careful to monitor how long it’s getting light for each day.

If you notice brown leaf tips of fronds or runners, there is a nutrient issue. Either there are too many mineral salts (which can often be caused by runoff from ice melts), or the quality of the water the plant’s receiving is poor. You may be able to work new soil in around your plants to help improve the soil quality. Using collected rainwater to water your ferns may also be a good decision.

Pests

A big cutworm sitting on a green sword grass.
Common pests of the perennial include cutworms, fungus gnats, thrips and other insects.

There is a form of root knot nematode which can cause symptoms very similar to Pythium root rot. Add beneficial nematodes that attack the harmful ones.

Some forms of caterpillar are known to feed on Boston fern, such as cutworms. Use Bacillus thuringiensis, also called BT, to defend against caterpillar damage.

Fungus gnats can also become a problem for the Boston fern. You can use neem oil to help combat the spread of these little gnats. Beneficial nematodes can also kill the gnat larvae in the soil.

Mealybugs, thrips, and scale insects can become destructive as well. All can be treated with neem oil, or alternately with an insecticidal soap.

Diseases

Root rot caused by a disease, appearing white and dry
The fungal disease that causes root rot can stunt the growth of this plant.

If the leaves of your Boston fern are going greyish in color and you know it’s not water-related, your plant may be suffering from Pythium root rot. This fungal disease can stunt the growth of your fern and eventually kill it.

To avoid this type of root rot altogether, buy plants that are free of pathogens. Plant them in sterile potting soil.

Another disease you might struggle with is Rhizoctonia aerial blight. This blight causes dark lesions or spotting on the leaves of your plant.

You can prune off any plant matter that has fallen victim to fungal diseases close to the base of the plant. This will visually improve the look of the plant. However, it will not treat the fungal infection, which still needs to be done.

YouTube video
Watch this video more more care instructions for Boston ferns.

Frequently Asked Questions

Is it safe to grow around my cats?

Any other true fern is generally safe to grow around your pets, as Boston ferns are nontoxic. Just remember that too much of a good thing is still too much. Even cat grass gets thrown up if your cat overindulges!

We get snow in the winter. Will that hurt my ferns?

While you are carrying out Boston fern care, overwinter your fern indoors, or keep it inside a greenhouse for protection from the cold. If they’re planted outside in a garden bed, you can mulch heavily around the base to help protect the root mass from cold. They can also benefit when covered with a cold frame.

My ferns develop yellow leaves that fall everywhere.

Remember, they love humidity. Mist them occasionally, and keep them away from heaters or radiators, as those can dry out the air. You can also place a saucer with some gravel and water in it beneath the plant to provide higher humidity levels.

Can Boston ferns survive outside?

They can, especially in zones 9 to 11. When temperatures dip below 50°F (10°C), shelter them or bring the plant indoors.

How long do Boston ferns live?

Each boston fern lives for 100-plus years.

Are Boston ferns an annual or perennial?

They are perennial plants in their hardiness zones.

How often do Boston ferns need to be watered?

Water outdoor plants daily, and water indoor plants when the top inch of soil is dry.

Do Boston ferns prefer sun or shade?

They need bright, indirect light. Remember that they are understory plants in their native ranges.

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