Boston Fern Care Guide – Nephrolepis exaltata ‘Bostoniensis’

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Perhaps one of the most widely used plants both indoors and outdoors is the Nephrolepis exaltata. Learn how to care for Boston fern, a gorgeous plant that can be both easy to care for or dramatic.

These plants are often seen in hanging baskets or vertical pots, ground cover, or mounted in walls. Because of its relatively low maintenance characteristics, this plant has become very popular.

Learn how to care for Boston fern - Nephrolepis exaltata

The Nephrolephis exaltata ‘Bostonesis’ is the most popular cultivar of the sword-like fern family. This plant is native to South America’s forests, and it has found its way to almost all corners of the world. Since its discovery, the Boston fern has been bringing the natural tropical vibes to houses.

When grown indoors, this plant’s fronds can grow up to 4 ft long and 7 ft in the wild. The fronds or sets of leaves of this plant gracefully reach out from the soil and eventually make slight arches. Each stem is composed of alternating green leaves that are pointed and grow shorter as they approach the stem’s end.

How To Care For Boston Fern – Nephrolepis exaltata ‘Bostoniensis’

Quick summary

Plant name: Nephrolepis exaltata ‘Bostonesis’

Common name: Boston fern, sword fern

Native to: South Americas

Lighting: Shaded areas to indirect light

Care: Keep soil moist and maintain high humidity. Can tolerate a bit of drying in the soil compared to most ferns. Keep away from drafts and frost. Do not place directly under the sun.

Common problems: Fern scales, nematodes, fungus, root rot and pests such as mealy bugs, spider mites, snails, and caterpillars

Toxicity: Considered non-toxic to both humans and pets

Bringing the Plant Home

When you bring your brand new boston fern home (or it gets delivered to your home), the first thing you need to do is inspect the plant for any pests and issues and if needed act upon it.

Once that is done, find a spot away from other plants in your home and place your new fern there for two weeks. If by any chance there were pest larvae in the soil they should show in two weeks and you will prevent the spread on other plants.

Since most of the Boston ferns being sold are already bushy, you may need to inspect your plant well. Check the soil and the underside of the leaves for presence of any pests and diseases. These plants are very susceptible to insect infestations.

Boston Fern Care

Light requirements of your Boston fern

In their natural habitat, Boston ferns, among other ferns, grow under large canopies of trees or on the bed of forests. Under these conditions, they receive filtered sunlight.

This is the best amount of light you should provide your plant. Soft morning light will make your Boston fern the happiest. As such, place it near an east-facing window where it can get enough sun for its leaves.

Other windows will also work provided that the plant is a few steps farther than when it is placed in an east-facing window. Soften the strong rays of the sun by adding a sheer curtain over the windows.

Although bright sunlight will help the Boston fern grow longer fronds, too much of it will burn them. The leaves of your plant will start to turn brown and eventually lose their delicate leaves over time. If you plan on growing them outdoors, place them under a shade to protect their leaves.

Watering requirements

Ferns are known to require consistently moist soil. Therefore they need frequent watering. One of the good things about the Boston fern is that it is perhaps the lowest maintenance type of fern as far as watering goes (however, it still needs plenty of water).

Allow your indoor plant’s soil to dry a little on the surface before giving it a good soak (it should still be a little damp ideally, but not wet). You should never allow the soil to dry out completely – while this fern is forgiving and won’t just die, if you forget once, it will suffer.

When grown in hanging baskets, the plant will not be in a deep container. This may require you to water your plant more frequently.

Despite being more tolerant to drying, too much underwatering will cause the leaves of your fern to dry out, turn brown and die. This isn’t just horrible for your plant, but also your home, as the tiny leaves falling off can create quite a mess.

Ensure that the excess water is drained to prevent any risk of root rot. Depending on the location of your plant and the amount of light it gets, you may need to adjust your watering schedule. Boston ferns placed indoors will require less watering than those outdoors.

When your ferns start to produce new croziers or new fronds, the plant will need to stay moist for longer times and may need more of your attention.

Humidity and Temperature

As with other types of fern, humidity plays a great role for your Boston fern. Specific to this cultivar, the Boston fern requires quite high humidity levels to really thrive.

Below 60%, you may risk getting crispy or falling leaves on your Boston fern. While the plant will grow with humidity levels lower than this, if you want to have lush magazine cover like foliage it’s best to keep the humidity high.

This plant will benefit from regular misting or being grouped with other plants as means of increasing air humidity. If your plant is hanged on a basket, then there is no way for you to use the technique using lined pebbles on a tray with water. At this point, you can opt to use a humidifier on days that are rather dry.

Awerage warmth is desired – don’t let your plant be exposed to temperatures lower than 50°F / 12°C. If you have your plant oudside during warmer months be sure to bring it indoors as temperatures start to drop.

Temperatures constantly higher than 75°F / 24°C also aren’t ideal.

Boston Fern

Pruning and Cleaning Boston Fern Leaves

It’s normal to get a couple of brown fronds when the plant gets old. Prune off any dry or dead fonds or parts of fronds (trim a bit of the brown tips to keep your plant looking healthy.).

Clean the base of your Boston fern as dead leaves encourage mold growth, negatively affecting your plants.

Boston fern can grow a bit unruly. You can curate how the plant grows by pinching the growth back a little and pruning the leaves.

Misting the leaves will keep them dust-free. You can also gently rinse the plant under running water (shower) – use lukewarm water and carefully work your way around the foliage (think of it as rain).

Fertilizing your Boston Fern

Since this plant requires nutrient-rich soil, fertilizing can be done at least 4 to 6 weeks only during the growing season.

Use liquid fertilizers with equal parts of nitrogen, phosphorous, and potassium and apply during your regular watering schedule. We would also recommend using half the recommended strength of your chosen fertilizer.

Boston ferns react negatively to being over-fertilized. The leaves will either gradually fall off or start turning brown. Using slow-release fertilizers during the start of the growing season may also help your plant grow healthier foliage.

During their dormant stage, which is in late fall and winter, refrain from fertilizing your plant. Your Boston fern does not use up much energy at this stage and will start slowing its own growth.

Tip: If you have a fish tank, you can use aquarium water to water your plant. This will provide it with many nutrients otherwise found in commercial fertilizers.

When to repot?

If you’ve got a baby plant you are probably looking at reporting every year as the plant gets bigger and overgrows the pot.

Mature specimens will only require repotting when the roots fill up the pot. It is pretty straightforward when determining when to repot your Boston fern.

Some signs that repotting is required are when roots start poking from the holes of your pot and when your plant seems to have stopped growing. These signs may tell you that the nutrients in the soil are not enough to sustain its growth.

When repotting, keep in mind the recommended type of soil. Additionally, choose a pot that is at least 1-2 sizes larger than your previous pot.

One other consideration when repotting is the type of pot to use. Unglazed clay and terra cotta pots will be able to expel moisture from all over their side because of their porosity. On the other hand, plastic and ceramic pots will retain moisture for a longer time. This only means that the type of pot you use will determine your watering schedule. Also, consider that ferns’ overgrown roots can easily break cement and clay pots that have already been withered by watering. Whichever type you choose, always ensure that the pot has enough drainage holes to prevent water from being stuck at the bottom of the pot.

The correct potting mix to use for a Boston fern

Your media for planting your Boston fern is crucial to keep it happy. Although the soil needs to be well draining, it must still be able to retain enough moisture.

Boston ferns prefer nutrient-rich soil that have enough room for oxygen. Mix your regular garden soil with some peat moss to help it retain moisture. Alternatively, you can also use sphagnum moss. Add some perlite to the mix to improve the drainage of your soil.


During repotting, it may be a great time to propagate your Boston fern. Although most ferns may be propagated using spores, doing this requires time and skill (and luck). As such, Boston ferns are more likely to be propagated by root division.

Carefully divide the plant by untangling the root ball and slightly burying it on top of your prepared pot. Do not fertilize newly propagated Boston ferns. Allow the plant to acclimatize and fully establish itself before giving it fertilizer.

Water your plant well after propagation and provide it with enough humidity and light to survive.

Caring for boston fern

Toxicity are Boston ferns safe?

Boston fern is safe and non-toxic to both humans and pets.

Commonly pests and issues with Boston ferns.

While Boston ferns are relatively low maintenance, they are very susceptible to pests especially when grown outdoors.

Their nature of growing very full make them hard to inspect regularly. Some pests that have the tendency to attack your plant include the usual mealy bugs, spider mites, and aphids. Because this plant is a type of Fern that can tolerate drying in between watering, it is a prospect for infestation.

Other pests include caterpillars and snails. Although more common outdoors, these pests prefer the moist soil around the pant. They can easily chomp down your Boston fern and eat most of its leaves in no time. Carefully isolate these pests and inspect If there are any eggs.

In addition, fungus gnats can also attack your Boston fern. These are small black flies that can be seen lurking on the soil of your plants. One of the most important risks associated with these bests is that they do not only suck the life out of your plant but also introduces the risk of fungal attack.

These insects leave vulnerable sites from where they fed on and can be attacked by bacteria and fungus. They can be treated by soaking the soil and leaves with your choice of pesticide allowing good drainage to protect the soil form any damage.

Lastly, although uncommon, your plants can be victims of nematodes. These pests usually come from improperly irrigated plants and may be from the garden where you purchased your plant. In pots, the best way to remove this problem is to wash off the roots of your plant and repot them. Proper sunlight and temperature can also prevent these from attacking the roots of your plant.

Nematodes can induce chlorosis or yellowing of the leaves and can also stunt the growth of your plant. After repotting, apply nematicide to ensure that the infestation is resolved.

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