Boston Fern Care Guide (Nephrolepis exaltata): How To Keep It Green & Healthy
Boston Fern Care and Background
Boston Ferns are beautiful houseplants, but they have a reputation for being a little fussy. Give them the right conditions and their long green fronds can create a lush tropical display indoors. Get the watering, humidity or placement wrong though, and those same fronds can quickly turn brown and drop.
The good news is Boston Fern care is easier once you understand what the plant actually wants. This guide covers everything from light and watering to humidity, repotting and fixing common problems.
With the planter being entirely made of building materials this is giving Industrial vibes. The green lacy Boston Fern then softens everything for an effective look.
The Boston Fern is one of the best-known indoor ferns, and if you want a reliable, fairly easy-care fern, a Nephrolepis variety is a great place to start. Victorian gardeners were especially fond of earlier species such as N. cordifolia and N. exaltata, and the "Boston Fern" itself, introduced in 1894, remains popular today because it suits warmer homes far better than many of those older, colder-growing types.
As Victorian Status Symbols
During the height of "Fern Mania" in the late 19th century, these plants were prized indicators of wealth and luxury. Families would proudly display them in their front windows on ornate pedestal stands to impress passing neighbors.
It has graceful, drooping fronds with a ruffled look, which is why it is sometimes called a "Sword Fern". It can be sensitive to chemicals, draughts, coal smoke and wood-burner fumes, so placement matters and this needs to be considered.
It can look fantastic in a hanging basket or anywhere the fronds can spill naturally over the edge of a shelf or bookcase. If you have the space, many owners hang them outside during the summer months on a shady porch or overhang.
This Nephrolepis exaltata 'Bostoniensis' growing in a blue bucket by bfishadow adds a splash of colour to the room.
Boston Ferns are readily available, relatively affordable and a great starter fern if you enjoy lush green foliage and the sense of calm they bring to a room. Because of its almost insatiable appetite for water, it pumps out large amounts of water vapor into the nearby air, thereby increasing humidity. They are also often associated with improved indoor air quality, although their practical effect in a normal home is limited.
How To Care For A Boston Fern (Quick Checklist)
| Care Area | Boston Fern Requirement |
|---|---|
| Light | Good indirect light. Avoid harsh direct sun. |
| Watering | Don't let them dry out fully. Keep soil lightly moist at all times but never waterlogged. |
| Humidity | High humidity will help prevent brown fronds. |
| Temperature | Normal household temperatures are fine. Avoid cold draughts. |
| Feeding | Feed occasionally during active growth. |
| Difficulty | Moderate care. Beginner-friendly once watering and humidity are understood. |
That quick overview covers the basics, but Boston Ferns get even more rewarding once you master their care throughout the seasons. Below is a deep dive based on my years of experience, covering everything from perfect lighting and watering to feeding, propagation, and troubleshooting.
Hi, I'm Tom!
If you're like me and enjoy the challenge of growing houseplants and getting them to thrive, then OurHouseplants can help. This website shares my knowledge and years of growing plants and provides my advice on properly caring for your indoor plant friends.
Boston Fern Photos
Boston Fern Care Guide
How Much Light Does a Boston Fern Need?
Reasonable light levels are needed. A Boston Fern will accept some full Sun and some quite shady areas, but for a happy and healthy looking plant you should aim for a fairly bright spot which does not receive harsh sunlight.
A North facing window would be ideal. East (or West in a pinch) would be acceptable, but South facing in full sunshine should be avoided.
Watering
How Often to Water a Boston Fern?
Because they need a moist growing medium for much of the year, you could easily be watering a Boston Fern several times a week during hot weather. Once a week or less over Winter.
All ferns are sensitive to watering routines and the Boston Fern is no different. The soil should be almost always moist in all seasons except for winter, during which you only need to water when the soil surface is dry.
Moisture is great, but do not over water to a point where the soil becomes sodden and completely saturated.
Try where possible to use rain water, but if you can't provide this, tap water is okay. Just make sure its been allowed to sit at room temperature for an hour because very cold water can shock the roots.
Moisture is great, but do not overwater a Boston Fern
Why Is My Boston Fern Turning Brown or Losing Leaves?
Brown fronds and fallen leaves are probably the two complaints owners see most often. If your Boston Fern is turning brown, crispy, or suddenly dropping lots of leaves, the problem is usually related to moisture, humidity, or a change in its environment.
A Boston Fern with dry brown fronds. This is usually caused by the plant being too dry, low humidity, or environmental stress.
The causes are usually linked to the same handful of problems:
- Dry soil. Boston Ferns do not like being allowed to dry out completely. If the root ball becomes too dry, the plant will often sacrifice older fronds first, leading to brown leaves and leaf drop.
- Low humidity. Dry indoor air, especially from central heating, radiators, or air conditioning, can quickly cause the delicate fronds to develop brown tips and crispy edges.
- Poor placement. Too much direct sunlight can scorch the leaves, while cold draughts, fireplaces, or heat sources can stress the plant and cause damage.
- Stress from changes. Boston Ferns can react when moved, repotted, or brought home from a shop, or exposed to a sudden change in temperature or humidity.
One of the tricky things to understand about Boston Ferns is that both underwatering and overwatering can sometimes result in brown fronds. If the soil has been staying wet for long periods, the roots can struggle to function properly and the plant may start showing similar symptoms.
If your Boston Fern has lots of brown fallen leaves around the base, this does not always mean it is dying. Older fronds naturally age and drop, and an established plant can recover from occasional stress. Remove the dead growth, correct the growing conditions, and new healthy fronds should gradually replace the damaged ones.
Do Boston Ferns Need High Humidity?
Boston Ferns do need a high level of humidity to really thrive. They absolutely love moist air, will accept average levels, but will suffer if humidity is low. Avoid placing near radiators or hot air vents which dry out the air considerably.
The Boston Fern looks fantastic as a stand alone plant.
This is the plant for the bathroom providing it has natural light and you can fit it in somewhere. Wherever it ends up, if practical mist the leaves regularly or check out some other ways to increase humidity.
Feeding
Feed using a general all purpose fertiliser at normal strength once every couple of months.
Best Temperature for Boston Ferns
Warm to average warmth during the day with a natural decrease in temperature at night will work wonders on the foliage, 16°C - 26°C (60°F - 80°F). In any case, no lower than 10°C (50°F).
Repotting a Boston Fern
Only repot if you are happy for the plant to grow bigger and even then, only when the roots have filled the existing pot. Take extra care to keep the fern at the same soil level it sat at before. It's really important not to bury the crown as this will lead to crown rot and the eventual end of your plant.
Keep your Fern well watered and warm which will let the fronds look their best.
Propagation
Did You Know?
In their native habitats, the plant sends out long, leafless, fuzzy runners called "stolons" that look like green tentacles. These runners crawl outwards, actively searching for neighboring soil to root and grow brand-new baby ferns. This can often happen with indoor grown plants too.
Some owners like to try and propagate by growing the spores which a healthy and mature fern will produce.
This is quite complex and time consuming, in addition some plants sold as "Boston Ferns" are not actually pure species and thus the plant won't usually produce viable spores anyway.
So it's usually more effective to divide a large plant into 2 or 3 pieces when you repot, or a more reliable approach is to look out for "baby" ferns appearing on "runners" at the edges of the pot. After they are large enough to handle they can be cut away from the "runner" and potted up in a similar compost mix.
How Fast Does a Boston Fern Grow?
Expect rapid and regular growth for much of the year when conditions are favorable. Growth will slow in cooler temperatures or if the roots have nowhere left to grow.
How Big Does a Boston Fern Get?
A max height of 90cm / 3ft and a spread of 180cm / 6ft after many (many) years.
Flowers
Almost all houseplants have flowers of some kind, even if quite rare. Ferns are the exception. No matter what you do you will never get the Boston Fern to bloom. Instead you may find it develops brown spots or "spores" on the underside of the fronds.
They may look like little back ants or some other type of pest, but they're actually fern spores. Photo by David Eickhoff
It's really important you can recognise these as they are all too often mistaken for some sort of insect infestation, at which point the plant is either thrown away or its owner reaches for the insecticide and sprays the fern constantly to try and get rid of them.
It's true they can look like Scale, but whereas Scale will appear in a random pattern, spores appear in rough lines and in an easy to see pattern. (See photo right).
Is the Boston Fern Poisonous?
The Boston Fern is non-toxic to people, cats and dogs.
Other Boston Fern Care Tips
Due to the plants sensitive nature of chemicals (and because it's too fiddly anyway) avoid leaf shine products. If you want to wash off any accumulated dust, run it under the shower for a few minutes.
Boston Fern Problems
Dark brown spots on the underside of the leaves
This is normal and shows you have a healthy plant!
Pests
Scale can be a problem and so can Red Spider Mite if the air around the plant is dry. You don't want an infestation of Scale as they are especially hard to remove from a fern as the plant itself doesn't take chemical pesticides well.
Therefore check the plant for these bugs every few weeks and remove the affected fronds completely or look at organic means of pest control. Red Spider Mite can be deterred by providing high levels of humidity (which the fern prefers anyway).
Brown leaves / fronds
In most cases this is a result of dry air, or allowing the soil to dry out too much before watering again. Annoyingly it can also be an indication you're overwatering.
The soil should be moist for much of the time, so think back over what you have been doing and adjust to better meet the Boston Ferns requirements. Cut the brown off as the green won't return.
Plants placed in harsh direct sunlight can also burn and give the brown you're seeing. This will be obvious if you can see your plant is getting sun on it's fronds during the middle of the day. If you conclude this is the cause, move your plant somewhere which gets more indirect light.
Why are my Boston Fern leaves falling off?
Some leaf drop is normal. By "some" I literally mean the odd couple of leaves every week or so. If you're getting more than that it's likely a watering issue. Namely not enough.
So many fallen leaves around this Fern. It looks alarming, but an established plant can recover surprisingly well once watering is corrected.
I'll be honest here. My watering routine for my ferns is not the best. The root ball does dry out completely from time to time and I get lots of leaves dropping. Sometimes you can "rake" the fronds with your hands and end up with 20 or 30 leaves falling onto the floor! However my Boston is pretty old and pretty big. 30 leaves is nothing to my plant so there is no lasting damage or negative effects appearance wise.
These are forgiving plants and will recover easily providing you don't leave it too long before noticing the roots are dry. Give it some water and after a few weeks, new growth will take off.
Yellow leaves / fronds
Many possible causes. It could be from using hard cold water, exposure to draughts, chemicals or toxic smoke, i.e. from coal fires. Natural aging also produces yellowing leaves. Study the care requirements detailed above and try to meet these requirements to keep the rest of the frond healthy and green.
Boston Fern crispy tips
Crispy brown tips are usually caused by dry air, underwatering, or the plant being too close to a heat source.
About the Author
Over the last 20 years, Tom has successfully owned hundreds of houseplants and is always happy to share knowledge and lend his horticulture skills to those in need. He is the leading content writer for the OurHouseplants Team.
Also on Ourhouseplants.com
Credit for the Boston Fern in the Blue Bucket - Article / Gallery - bfishadow
Credit for the Boston Fern showing its leaf spores - Article / Gallery - David Eickhoff