Houseplant · Nephrolepidaceae
Boston Fern
Nephrolepis exaltata
Give it steady moisture and humid air, and the Boston fern unfurls into a fountain of soft green fronds.
Bright indirect
61–70°F · 16–21°C
USDA 10–12
2–3 ft · 0.6–0.9 m
Overview
The Boston fern is one of the easiest ferns to keep indoors, prized for the arching fronds that spill over the rim of a pot or hanging basket. It belongs to the genus Nephrolepis and grows wild in humid tropical forests, which is exactly the kind of warm, damp air it still wants on a windowsill. Give it a bright spot out of direct sun and it grows fast, filling out into a lush green mound.
What this fern asks for is steady moisture and high humidity, the two things ordinary indoor air tends to lack. Dry it out or park it next to a heater and it tells you straight away, dropping leaflets and browning at the tips. Keep the soil evenly moist and the air humid, though, and it forgives almost everything else.
It earns its place in a home with pets and children, since the ASPCA lists it as non-toxic. That makes it a rare houseplant you can grow without worrying about a curious nibble, and a handsome one at that.
Care
The short version: bright indirect light, soil kept evenly moist but never soggy, and humid air around 61°F to 70°F (16°C to 21°C). Feed monthly through the growing season and divide the clump every few years.
Light
Give the fern bright, indirect light, the kind near a window but out of direct sun. It also takes medium light, partial shade, and even full shade, so a dim corner won't kill it, though strong sun will scorch the fronds.
Water
Keep the potting mix evenly moist but never saturated, easing back only a little in winter. Let it dry out and the fern sheds leaflets and browns at the tips, so consistent watering matters more than anything else.
Soil
Plant in a peaty, soil-based mix that drains freely yet holds moisture, such as a blend of peat and vermiculite. That balance keeps the roots damp without leaving them sitting in water.
Temperature
The fern is happiest between 61°F and 70°F (16°C to 21°C), ordinary room range. Keep it clear of cold drafts and the dry heat of radiators, both of which dry the fronds.
Humidity
This is a high-humidity plant, and dry indoor air is its main enemy. Raise the moisture around it by double potting or standing the pot on a tray of wet pebbles, which works far better than misting.
Feeding
Feed monthly from spring to early fall while the fern is growing, then stop over winter. Use a weak, half-strength liquid feed or a slow-release houseplant fertilizer, since the roots scorch easily on a strong dose.
Pruning
Trim old or damaged fronds off at the soil line to make room for new growth. If the plant has dried out and shed, you can cut the fronds back to about 2 inches and let it regenerate from the base.
Repotting
Divide the fern every few years in spring, once the clump has filled its pot. Watch for roots circling the container and crowded fronds losing vigor, both signs it's time to split and refresh.
Size & spacing
Indoors the fern reaches about 2 to 3 feet (61 to 91 cm) tall and just as wide, so give it room to arch. The spreading fronds look best where they can drape, as in a hanging basket or on a stand.
Troubleshooting
Almost every Boston fern problem traces back to dry air, dry soil, or a stray pest. Read the early signs on the fronds and you can step in before the plant sheds in earnest. Match what you see below, then act while it still helps.
Browning fronds and leaflets dropping all over the floor
Dry air and dry soil are the usual culprits, and the damage shows up first as browning at the leaflet tips before the plant starts shedding. Keep the mix evenly moist, raise the humidity with a pebble tray or by double potting, and pull the plant away from radiators and drafts. If it has dried out badly, cut the fronds back to about 2 inches and let it push fresh growth.
Fix:
- Keep the potting medium evenly moist but not saturated
- Raise humidity by double potting or setting the pot on a tray of wet pebbles
- If badly dried out, cut fronds back to about 2 inches to regenerate
Sticky fronds with cottony fluff or small bumps
Those bumps and cottony clusters are scale insects or mealybugs, and the sticky film they leave behind is honeydew. Cut off and bin any badly infested fronds, then treat what's left. Check every new plant before it joins the others, and keep an affected fern away from the rest until it's clean.
Fix:
- Remove and discard heavily infested fronds
- Treat remaining foliage for scale or mealybugs
Toxicity
Good news for pet owners and parents: the Boston fern is safe. The ASPCA lists it as non-toxic to cats and dogs, and no toxic compound has been reported in the plant, so it sits happily within reach of curious animals and children.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists Boston fern as non-toxic to cats, with no toxic principle on record, so a curious nibble is nothing to worry about.
Dogs None
Dogs are in the clear too. The ASPCA names this fern non-toxic to them, and a chewed frond won't poison your pet.
Horses Safe
No toxic compound has been reported in the plant, so grazing on a frond poses no poisoning risk to horses.
Rabbits Safe
A rabbit can taste the fronds without harm, since the fern carries nothing toxic. Plenty of greens still make a better staple than fern leaves.
Livestock Safe
Cattle, goats, and sheep face no toxic principle here, so a mouthful from a stray plant is safe.
Birds Safe
The fronds hold no known toxin, which makes this fern a safe bit of greenery around birds.
People Safe
Boston fern is harmless to people, and a child who mouths a frond is fine. It isn't grown as food, so there's no part worth eating.
Varieties
A handful of named cultivars turn up most often, differing mainly in size, frond texture, and color. These are the ones worth knowing.
'Bostoniensis'
This is the classic Boston fern, with gracefully arching fronds that reach about 4 feet long and 6 inches wide.
'Compacta'
A tidier, smaller version of the standard fern that suits tighter spaces.
'Florida Ruffle'
Its fronds are denser and more finely cut, giving the plant a soft, ruffled look.
'Rita's Gold'
A selection grown for its chartreuse to golden-green new foliage.
How to propagate
Boston ferns are easy to multiply, and the plant does most of the work itself through dividing clumps and self-rooting runners.
DivisionEasy
Spring · A few weeks to a couple of months to root and resume growth
Dividing the clump is the most practical way to make more. In spring, slice the root ball vertically into halves or quarters and keep as many fronds on each piece as you can, then give the divisions a few weeks to a couple of months to root and start growing again. The fern also spreads on its own through runners that root where they touch soil, and in the wild it reproduces by spores carried on the undersides of the fronds.
Offsets & pupsEasy
Spring to summer · Several weeks once a rooted runner is separated
The fern throws out runners that grow small plantlets wherever they meet moist soil. Once a runner has rooted, snip it free from the parent in spring or summer, and the new plant settles in within a few weeks.
Myths
Boston fern is poisonous to cats and dogs like so many houseplants.
This one is safe. The ASPCA lists Boston fern as non-toxic to both cats and dogs, so it earns a spot in homes where other houseplants can't.
Misting is the best way to give a Boston fern the humidity it craves.
Misting does little for humidity and leaves the fronds damp, which invites foliar leaf spot. Double potting or a pebble tray raises humidity far more reliably and keeps the leaves dry.