How to Get Your Boston Fern to Thrive
Help! My Boston Fern Hates Me! How to Care for Your Boston Fern
Boston Fern Nephrolepis exaltata ‘Bostonesis’
There simply isn't another plant that screams junglow like the Nephrolepis exaltata ‘Bostonesis’, commonly know as Boston Fern or Sword Fern. They're from S. America, lush, tropical, vibey, a bit un-tamed and they get massive with fronds anywhere from 4'-6' when they're truly happy. I have received nothing but joy (and countless questions) as to how I get mine to thrive the way I do...so I'm here to share everything.
If you feel like your Boston Fern hates you...it just might, but it's ok! We can repair the relationship so don't fret.
First, I'm going to ask you a few questions, and I want you to keep your answers in mind while you read.
Have you ever potted her up? a.k.a transplanted her into a bigger pot?
How long has she been in the same pot? Is she root-bound?
Is she in the same pot and/or soil you brought her home in?
What type of pot do you have her in?
Have you fed her (during growing season)? She may be in root-lock.
How deep and how often do you water her?
Are you humidifying the air around her?
Where do you have her hanging? (Morning sun, direct/indirect light/vents)
Someone asked me today if Boston Ferns needed to die back for winter to thrive. I had no clue, so I dug into it a bit. The answer to that question is no...Boston Ferns cannot die back and come back the next year. If you live in a cold climate that dips to 40 or lower, they must be treated as an annual or brought inside for over-wintering. They are only a perennial in hot, humid climates. It is possible to revive a fern on it's last leg, if there are a few healthy shoots left...but they cannot survive freezing and they simply won't come back from it no matter what you do.
My Boston Fern in it's winter-spot between a bright East & North-facing window
If you have failure to thrive (as it is with any plant) it's going to be 1 of 8 things:
Sun - Ferns like bright-indirect light. The prefer Northern sun or you can put them close to an East facing window a few feet from the direct rays. You can also diffuse their light indoors with a sheer curtain. They love light but direct sun will burn them.
Water - Boston Fern is not a "water whenever I remember" plant. They need a ton of water, and cannot dry out ever - so be sure to deep water. If you don't know how, read: How to Deep Water Your Plants. Ferns are like all rainforest canopy dwellers - they absolutely hate being dry , so don't let it happen. Water them often during the growing season and warmer months - if they are outside in hot weather, you may need to water them every one to two days. Check them daily in growing season, and weekly during fall/winter, by poking your fingertip down to the first knuckle, to see if the first inch is dry. If so, take them to the hose, or if indoors to the sink (if you have a spray nozzle) or even better...put them into the shower and let it rain! When your fern is so heavy you can hardly lift it and no more water is draining out of the bottom...it's been deep watered. Flush the Soil: Be sure to water your fern once a month with distilled water to rinse out any salts in the soil. If you have high chlorine content in your water, use distilled or filtered water to water your fern.
Temperature - They love it warm and muggy and they don't thrive in cold. Boston Ferns enjoy temperatures between 60°F – 75°F /15°C – 24°C but will tolerate temperatures as low as 50°F /10°C.
Food - Through the growing months - I use Fox Farms Grow Big (1/4-1/2 strength) and I often throw some extra worm-castings on the top of the soil if I haven't transplanted in awhile, for slow -release fertilization as i water.
Soil - I only use Fox Farms Ocean Forest for all of my plants. It contains bat guana and worm castings along with a host of other organic fertilizers. For plants like ferns, that require additional moisture capacity, I add some vermiculite to the mix.
Pot - If you haven't re-potted since you got her, or in awhile...she might be in soil that lacks nutrients, or it may have run out of space. If it's in a terracotta pot...take her out right away and put her in plastic or another sealed, non-porous pot. The key is keeping her humidity levels high and her soil moist at all times.
Pests - Some pests that have a tendency to attack your fern include the usual suspects: mealy bugs, spider mites, and aphids. Because your fern can't tolerate drying in between watering, it is a perfect environment for infestation. Other pests that will eat your plant are caterpillars and snails, who prefer the moist soil around the plant, but they tend to be a bigger problem when your Boston Fern is hanging outdoors. Fungus gnats can also be a problem, as they suck the life out of your plant and can introduce the risk of fungal attack. So, keep your eyes peeled for signs of infestation.
Environment - Boston Ferns (all ferns actually) hate air vents and drafts, so cover or avoid them like the plague. They also need a ridiculous amount of humidity. She likes 60% humidity and up, which is why I highly recommend keeping a diffuser/humidifier running next to her at least 12 hours a day.
Misting only increases humidity levels for up to an hour and your jungle beast wants it muggy.
If you can't do a diffuser, employ a pebble tray with water under her pot. Be sure the bottom of the pot doesn't sit in the water.
The last way I would suggest on how to increase humidity, is plant groupings. Just like people, plants like to be with other plants and they increase the humidity around themselves when they are grouped together.
Deep watering my Boston Fern in the sink...once. We moved these sessions to the shower for obvious reasons.
My strat and schedule: I deep water weekly (in the shower, because she is simply too big for my sink) and I literally run diffusers 12 hours every other day for all of my high-humidity plants.
I found aesthetically pleasing and relatively cheap 12-hour diffuser/humidifiers on Amazon for $29 and I have strategically placed them everywhere I have plants that need the humidity bump. I often put some essential oils in them, so they serve a dual purpose. That's not an affiliate link, so be sure to price-shop. It's just a link to exactly the ones I bought and used. I have had them running 12 hours a day for almost a year, and they're still going strong.
One thing I have learned about most plants is...when they aren't growing, and all of the above boxes are checked, then what I've found is that pruning them back usually works wonders. I read up a bit before I brought her in to see what kind of transitional changes to expect and saw a lot about Boston Ferns literally falling apart at the seams and shedding all of their leaves, indoors through the winter. I admittedly had a bit of a panic attack...but I am a plant whisperer, so with 100% clarity of intention and a little bit of juju, I decided that would not be our fate.
What I got out of all of that reading was, if your Boston Fern isn't thriving and/or you know it needs to be potted up into a bigger pot, wait until you see new growth in the spring, then cut every frond back that isn't healthy and thrivey to 2". Everything I've read says that she'll come back strong.
Disclaimer: I haven't had to prune any of my Boston Fern (yet.) However, I prune and propagate every other plant I have and I have done a radical pruning on other non-conformant plants, with great success, so I have no reason to distrust this information.
Story-time: So, I had a not at all thrivey Tradescantia Zebrina with a browning, almost leafless crown that I decided must need potting up. In the process of my "saving it's life"...my clumsy-ass proceeded to drop it right on it's head as I was getting it out of it's old pot. I looked down and I was devastated by the plant carnage all over the table. I broke most of it's gorgeous, 2-3+ft long tendrils. I was honestly in tears.
When I finally got over my meltdown (and stopped incessantly apologizing to my plant) I cut all of those beautiful broken vines into 6"-8" strands and stuck at least one leaf-node each in Clonex Rooting Gel and placed them in jars all over my office (changing/freshening the Clonex Solution water in the jars every 5 days). Then, I put the roots and connected stubs that remained in tact, into the new pot and deep watered with a capful of Clonex Solution per gallon of water.
In 3 weeks time, I had new far healthier growth in the new pot, and once I planted a bunch of the rooted vine cuttings in there, I had a gorgeous, full, thriving plant...and 4 more for the shop!
Zebrina Rainbow Quadricolor - my beautiful mother plant.
As a rule, if/when you find yourself in a similar situation (be it intentional or accidental) - be sure you place the cuttings all the same way, so you remember which end was the root end and which side wasn't - because sometimes with some plants, it matters.
I truly hope you found this post helpful (for you...and your fern) and that you get vibin' in your happy place with your Boston Fern. May the two of you live Happily Ever After!
Peace & Love