Boston Ferns -- Growing Nephrolepis Ferns

Growing Conditions and Tips, Propagation, Repotting and Varieties

A person pricking out clumps of young propagated Nephrolepis exaltata (Boston fern)
Mark Winwood/Taxi/Getty Images

The Boston fern is the most well-known of the Nephrolepis ferns, but all of them share certain desirable traits. They are relatively tough ferns, with a higher tolerance for light than other species. And they are typically attractive, with long, graceful fronds bedecked with tiny leaves. As far as ferns go, these are also more tolerant of dry conditions and easy to propagate. Finally, they can be used in any number of situations, including pedestals, hanging baskets, groupings, or lush specimen plants on the right windowsill.

Growing Conditions

Here are tips on growing Boston ferns:

  • Light: Bright, indirect light. Some varieties of Nephrolepis can be trained to handle almost full sun, but most prefer filtered, dappled light.
  • Water: Keep the root ball moist at all times. Mist frequently, depending on the ambient humidity.
  • Temperature: These ferns can survive the occasional blast of cold, down to 50ºF or even slightly colder for a few hours. However, they really thrive between 60ºF and 75ºF.
  • Soil: A loamy, rich, organic mixture. Make sure their drainage is good to avoid rotting their roots, which will be evident if the plant is beginning to lose leaves or appears waterlogged. It's a good idea to choose a soil that contains some organic material.
  • Fertilizer: During the growing season, feed with liquid or slow-release pellets. If you're not happy with the fern's progress, it won't hurt to slightly up their fertilizer within reasonable limits.

    Propagation

    These are very easy plants to propagate: simply divide the plant while repotting in the spring. Even very small divisions will root if care is taken with them (meaning plenty of warmth and humidity). Make sure each division has a section of healthy roots. Ferns can also be propagated by spore, but this is somewhat more difficult.

    Repotting

    In the spring, repot into fresh compost, even if it's not necessary to move up in pot sizes. Divide plants at this time and multiply your collection. Common signs that a plant needs repotting include overcrowding and wilting leaves, so keep an eye on your Nephrolepis for any tell-tale signs of stress. Failure to repot these plants could cause death.

    Varieties

    There are actually two species of Nephrolepis found in cultivation: N. cordifolia and N. exaltata. N. cordifolia features erect fronds up to two feet long. N. exaltata is the more common. Varieties include:

    • N. exaltata. Known as the sword fern, this plant has stiff, upright fronds up to three feet.
    • N. exaltata bostoniensis. This cultivar was discovered in 1894 and has graceful, drooping fronds.
    • N. exaltata bostoniensis varietals. There are many varieties of this popular fern, featuring frilly, ruffled or interesting fronds. Some of the most popular varieties include 'Whitmanii,' or lace fern, and the 'Rooseveltii.'

    Growing Tips

    Nephrolepis ferns appreciate a little TLC.

    They like to be kept in warm, humid conditions ​and don't appreciate being blasted by air from outlets or vents. Remove dead fronds and occasionally rotate the plant to keep it growing evenly. During the winter, when the plant isn't growing, you can reduce watering, but your fern should never be allowed to completely dry out. Make sure to maintain a balance of elements for best results; as is true of much of the rest of life, growing the ferns is all about moderation and a sober approach that doesn't overemphasize any one element.