How to grow Boston fern

Nephrolepis exaltata · Sword fern

A classic houseplant fern, up to about 90 cm tall and wide, with feathery fronds that grow upright, then arch and droop with age; it also spreads by thin runners that root into new plants.

Quick facts

Type	Houseplant
Family	Nephrolepidaceae
Light	Partial shade
Frost	does not tolerate frost
Soil for sowing	from 10 °C
Where it grows	At home

When to plant

Sow straight into the bed after your last spring frost, once the soil has warmed.

Frost dates · When to plant

Care

At home

Stage	Watering	Temperature	Feeding
Growth	every 5 days	16…21 °C	balanced (NPK), 14 days into the stage; balanced (NPK), 44 days into the stage; balanced (NPK), 74 days into the stage; balanced (NPK), 104 days into the stage; balanced (NPK), 134 days into the stage; balanced (NPK), 164 days into the stage; balanced (NPK), 194 days into the stage
Winter rest	every 10 days	10…21 °C	—

Growing notes

Light

Bright, filtered light, such as an east-facing window or behind a sheer curtain; direct sun burns the fronds.

Soil

A moisture-retaining but well-drained mix, such as peat-free multipurpose compost. Never let it dry out completely, but do not let it stay waterlogged either.

Care

Keep the compost evenly moist from spring to autumn, ideally with soft water, and water more sparingly in winter, when soggy compost rots the roots and fronds. It likes 16–21 °C and high humidity — stand it on a tray of wet pebbles, group it with other plants or mist it; dry air browns the frond tips. Feed with a half-strength balanced liquid fertiliser monthly while it grows; too much feed browns the frond ends. Cut off old fronds at the base and divide or repot every few years in spring. Non-toxic to cats and dogs.

Pests and diseases of Boston fern

Sources

Figures checked against these sources.