With such a graceful look, the Boston fern might seem like a demanding plant, but it’s not all that hard to keep once you get the hang of it.
In this article, we’ll go over a detailed Boston fern care guide that tackles the ideal growing conditions, propagation, disease protection, and the best places to grow the bushy plant.
Let’s jump right in!
Raising a Boston fern (Nephrolepis exaltata) is fairly easy for people with light gardening experience.
In fact, somewhere out there in Virginia, a family managed to keep their Boston fern thriving for a whopping 114 years!
While you might not get yours to live as long as that family did, you can aim for years and years of luscious leaves. After all, it’s a sturdy perennial.
However, you’ll still need to cover the fern’s basic growing conditions, from temperature to watering.
Although the Boston fern isn’t particularly picky, there are a few aspects that you need to keep in mind if you want that dense and brilliant green look.
Let’s take a look at seven of those growing conditions:
By their nature, Boston ferns are tropical. This means that they’re more likely to survive hot weather than freezing winter nights.
For best results, you’ll want to keep your fern at a temperature of around 65°F at night and 95°F for the daytime as a maximum limit.
That said, your Boston fern might be better prepared to handle winter if it’s been established as an outdoor plant from the get-go. Meanwhile, potted indoor plants could be more susceptible to fading during the cold months.
However, many people still prefer keeping their Boston fern in pots or baskets. Aside from the aesthetic aspect, this helps them to quickly move the plant around with extreme temperature fluctuations, especially during intense summers or winter nights under 40°F.
People living in USDA hardiness zones 9-11 will have little to no trouble maintaining the required temperature range for the majority of the year.
These hardiness zones cover some parts of:
When you go through the list, you’ll see that the main theme across all these southern states is that there’s no major frost to worry about. They’re also closer to the topical range that the Boston fern loves!
If you’re not sure where your city lies in terms of hardiness zones, you can always check out the ranges on the USDA map. Alternatively, you can just get in touch with the local extension office in your county for more details.
Temperatures aside, being a tropical plant also comes with high humidity demands. The exact moisture content percentage will vary from one Nephrolepis exaltata cultivar to the other.
For instance, the Florida Ruffle will appreciate a higher humidity level than the Dallas Jewel cultivar. However, 50% is usually a good place to start with tropical plants.
So, if you live somewhere with dry air, you might want to invest in a small room humidifier and keep the Boston ferns as a strictly indoor plant.
Growing on pebble trays and using manual misters once or twice every week are also possible fixes, but they rarely suffice on their own. Some people might even use the natural humidity around kitchens and bathrooms to boost the plant’s growth.
Although you don’t need to water your Boston ferns daily, keeping the soil dry is a quick way to kill the plant.
Meanwhile, there’s also such a thing as over-watering a Boston fern, and it’ll turn the leaves yellow and wilted. Plus, it’ll increase the risk of root rot, especially during the winter when the plant goes dormant.
In fact, dropping from multiple waterings weekly in the spring and summer to once per month might get the job done for the winter.
To take the guesswork out of the process, you can always just test the soil’s saturation level by dipping your fingertip. The top layer (1-2 inches deep) should feel moist but not all the way soaked, so if it’s dry, you’ll know that you’re overdue for a watering.
Just remember to use distilled or filtered water. Using hard tap water can bring down the plant’s vitality and cause burned tips with all the extra salts.
Boston ferns bounce back very well after cutting back even half of the fading fronds.
Most people prune before repotting, but you can always do it for aesthetic reasons, too.
For one, it can help you tame down the volume if you’re not a big fan of the giant bushy plants. On the other hand, you can use it to get rid of any fading leaves or leggy stems to keep the fern looking fresh.
However, it’s crucial to avoid trimming during extreme weather, both hot and cold.
The bushy fronds help warm up the roots during the winter and provide shade during the scorching summer. So, aim for a timeframe with a moderate temperature around 60-70°F.
When you prune, make sure to cut the leggy stems at their base, leaving around four inches peeking from the soil. Just try your best to avoid cutting the top of the fern.
As is the case with any pruning session, if you’re using garden shears or snips, make sure they’re sharp and clean to save yourself the hassle.
Provided that you use a slightly acidic soil mix rich in organic matter, you’ll only need to use fertilizers sparingly.
In most cases, boosting the nutrition on a monthly basis during the growing season (spring and summer) is enough.
Water-soluble options with a boost in nitrogen and potassium can get the job done, but you’ll need to dilute it by half.
Just try not to go overboard with the fertilizer, especially liquid ones with high bioavailability. When the plant doesn’t need them, they can show a counter effect by turning the leaves brown with crunchy tips.
When you consider the fern’s natural habitat, you’ll quickly realize what kind of sun exposure it needs. Usually, it would grow in canopies under taller plants, which creates a soft and shaded spot.
In your home garden, you’ll need to mimic that by providing around two hours of indirect sunlight every day. Keep in mind that the early morning and late afternoon sun works best.
If you expose the fern to too much light, it’ll turn the leaves yellow all over. Meanwhile, excessive shade could lead to a droopy, sad look.
Of course, how you replicate the plant’s natural light requirements depends on where exactly you choose to put your Boston fern.
Boston ferns will grow nicely both indoors and outdoors, and each placement choice has its appeal.
For the most part, their care routines are similar. The main difference to look out for is the sunlight exposure, though.
The beauty of growing ferns in pots and baskets is that you can easily adjust the temperature and sunlight exposure by moving them around.
For instance, you might want to keep your Boston fern in a south or west-facing window during the fall and spring at a distance of around 2-5 feet. This will give a healthy dose of filtered sun daily.
Meanwhile, you can move it a little further from the window when the sun gets more intense in the summer to avoid over-drying the soil and burning the leaf tips.
Using sheer curtains to dim out the light is also a handy trick to keep up your sleeve!
It’s possible to keep potted ferns and hanging baskets outdoors, too. In that case, it can be easier to move the plant to a shaded part when the sun gets too intense in the warmer months.
However, if your outdoor Boston fern is rooted in the ground, you’ll need to get creative with proving the shade.
If you’re still planning the landscape, you can grow it in a taller plant’s canopy. Alternatively, you can prop up a slatted garden awning whenever you don’t have the flexibility of moving the fern around.
On the other hand, you’ll need to winter the plant to get to survive the dormancy. Most people opt to bring the fern indoors during the colder months, but if you want to keep it outdoors, make sure to mulch generously to keep the roots valid for the next growing season.
Pots and baskets are the most common option for both indoor and outdoor Boston ferns. However, they can still root directly in the ground, too.
There are two ways that you can grow Boston ferns in the ground. Choosing between them depends on the available space and whether you want to keep companion plants in the same spot.
Here are your options:
Boston ferns don’t flower, but they can act as dazzling upright accents for many annual flower beds.
For instance, if you have begonias growing somewhere in your backyard, you can pair them with the fern. The luscious fronds will complement the colorful blooms perfectly during the summer.
On the plus side, keeping the fern in the same spot can also help you mark where the begonias are rooted. This way, when the plant fades in the fall, you won’t accidentally dislodge its roots.
Alternatively, you can also grow the Boston fern in the ground next to wishbone flowers. They’re suitable for zones 2-11, and they won’t mind the shade at all.
If you’re willing to go for a bold statement piece in your home garden, you can opt to let the fern spread over a larger area, creating a bushy ground cover.
Just keep in mind that it’ll grow taller and bushier than the typical options, like junipers and mondo grass. Usually, you can get an average coverage of three-by-three feet from each fern.
The Boston fern isn’t immune to a lot of plant diseases and pests, and adjusting the growing conditions will only take you so far if you don’t know how to protect it.
Let’s take a look at some hiccups to expect with Boston ferns:
The most common problem with Boston ferns is dried fronds.
In some cases, it’s not really a serious issue, and you can just prune the disease parts and call it a day.
However, if the dryness and discoloration are extensive, it could indicate an underlying problem with over fertilizing, irrigation with hard water, or low humidity levels.
With frequent watering and indirect sun exposure, there’s always a risk of developing Pythium root rot with bushy plants like the Boston fern.
The issue with diseases like this is that they can be challenging to diagnose and treat. If the rot takes over, your best bet is repotting and discarding all the infected soil entirely.
Keep in mind that you’ll have to watch the transmission to nearby plants if your fern is rooted directly in the ground.
Boston ferns are susceptible to your typical array of garden creepers, including:
Most of these will leave holes and sticky residue all over the diseased fronds.
If you notice signs of infection, you can try removing the snails, worms, and slugs by hand. Meanwhile, diluted isopropyl alcohol and neem oil can help with mealybugs and scales.
With fronds that dangle downward, the Boston fern makes for a hanging basket plant. Its bushy volume looks almost like a green explosion that can add quite the eye-catching profile to any backyard or porch!
However, not everyone gets lucky keeping this beauty on the first try.
Besides the main growing conditions, let’s take a look at a few tips and tricks that can keep your hanging fern baskets looking fresh!
While it’s tempting to choose hanging baskets solely based on their ornamental looks, that’s not always practical.
The key to picking the right hanging basket for your Boston fern is finding something that helps the soil retain a consistent level of water without leaving the plant waterlogged.
Keep in mind that plastic planters can often reduce the loss to evaporation, especially when compared to terracotta pots. Thankfully, most nurseries already send out their ferns in plastic containers, so you won’t have to worry too much about that.
If you want to get an extra visual boost, consider double potting by placing the plastic planter in a larger terracotta planter with a drainage hole and line it with sphagnum moss.
Unlike outdoor plants growing in the composted ground, a hanging Boston fern might need slightly more care when you’re picking the soil mix.
The best soil to choose here is something with a lot of organic matter content, high moisture retaining power, but just enough drainage to keep mold and mildew away.
You can mix up the following components to provide a suitable growing medium:
- High-quality indoor compost (provides the bulk of the nutrients)
- Coconut coir (works on adding some drainage capacity)
- Coarse sand (balance the texture out)
- Perlite (a minor portion)
It’s always possible to use your finger to check the soil’s water content, but with hanging Boston Ferns, this can be a little tricky. After all, it gets very bushy, and reaching for the soil isn’t always as easy as it sounds.
Instead, you can lift the basket up with your hands to see how heavy it is. A soil mix that still has enough water will be significantly heavier than a fern that’s desperate for water.
Keep in mind that it could also be better to add a portion of water and then wait for it to get distributed before you go in with the rest. This can help the soil retain moisture better.
Assuming that you care for your Boston fern right, it can grow crazy after a while. That’s where pruning comes in handy.
However, it’s not obligatory to go heavy into the pruning. After all, some people love the full volume on a Boston fern.
Either way, it’s mostly a matter of aesthetic preference. So, consider which look you find more suitable for your home garden and trim carefully.
Epsom salt (magnesium sulfate) can often give a nutrient boost to potted plants, and the Boston fern is no exception.
For each gallon of water, you can add two tablespoons and use it every month if your plant is in bad shape. However, if it’s not struggling, and you just want to give it some extra TLC, twice annually could be enough.
Just keep in mind that you might not need to use commercial liquid fertilizer in combination with the Epsom salt soak. This nutrient overload may be a bit much for the fern.
To propagate your mature Boston fern, you’ll have to choose between two possible routes.
Let’s take a look at the highlights of each method and how you can tackle it like a pro:
The division method works best for potted Boston ferns because it requires removing the plant from its medium.
It usually also goes hand-in-hand with repotting since you’ll probably want to keep the plant from getting too bulky. This way, you can get two (or more) moderate-sized ferns from an overgrown one.
- Wait for the soil to dry a bit. It’s better to do this right before watering.
- Snip away any discolored, dried, or wilting fronds.
- Pop the plant out of its container.
- Get a serrated garden knife and work your way into the root-bound ball.
- Depending on how large your fern is, you can either divide it into one-eighths clumps, quarters, or equal halves.
- Pot the new clumps separately.
Mature Boston ferns release runners (stolons) that can root and form a daughter plant when it gets in contact with the nearby ground. This could happen naturally if you don’t trim and prune and plant regularly.
Although it’s not as common as the division method, you can still use these runners to propagate your Boston fern.
To intentionally propagate this way, all you need to do is spot the viable runners at the base, remove them, and pot them separately to get a new plant established.
However, if you plan to go with this method, make sure you don’t cut back the stolons away when you’re pruning.
While most Boston ferns are already low-maintenance enough, you might be looking to narrow down your options to fit your needs.
For instance, both the Dallas and Whitmanii cultivars can be suitable options for people who can’t keep up with the humidity levels since they can tolerate drier conditions. This makes it easier to grow either ferns indoors.
The Dallas is also a petite fern that can survive with even less light than most other cultivars.
The Golden Boston is also overall easy to care for, but its fronds aren’t as bright green as the others. Instead, it’s more yellow-toned.
The Boston fern care requirements are relatively simple to follow, even for people who aren’t gardening experts.
Mainly, you have to adjust the temperature, humidity, and light exposure to match the plant’s tropical nature. Once you get these basics down, you could touch up with fertilizing boosts and pruning the faded fronds every now and then.
With a bit of care, you’ll get to enjoy a vibrant and full fern either indoors or outdoors!
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.