Botanical Name — Nephrolepis exaltata
Common Name — Boston Fern, Sword Fern
Plant Family — Lomariopsidaceae
Nephrolepis exaltata is a lush, shrubby fern native to tropical regions around the world. Humidity-loving, it grows naturally in moist ecosystems like swamps and forests. Extremely large specimens can reach as high as 1.5 meters high. Occasionally epiphytic, it grows on the surface of one kind of palm, Sabal palmetto.
- Boston Ferns grow best in light shade, or medium to bright filtered sunlight. However, an hour or two of direct sunlight in the morning could benefit this plant and encourage it to grow faster. An east facing window would be ideal.
- Nephrolepis exaltata will thrive in high humidity environments. Ambient moisture is essential to keeping these feathery fronds lush and green. A windowed bathroom or kitchen where there is plenty of humidity is a great spot.
- A temperature of about 70°F is ideal, avoid anything below 60°F.
- Consistent temperature is key. These tropical ferns are not very tolerant of temperature fluctuations or cold, drafty air.
- Keep soil evenly moist, but not soggy. Water when the top of the soil feels dry to the touch.
- Mist plants daily to keep humidity levels high.
- In their native environment, Nephrolepis exaltata are spoiled by a rich, moist, well-drained soil, and fertilized by decaying organic matter. Coco coir and compost are excellent amendments to ensure that soil provides adequate moisture and is high in organic nutrients. However, under most circumstances, a general all-purpose potting soil will suffice for this plant.
- Nephrolepis exaltata are ferns and therefore reproduce by spores, not flowers.
- Fertilization is generally not necessary, but if you choose to fertilize, feed your fern once every two weeks with a water-soluble fertilizer diluted at half the recommended strength. Ferns love fish emulsion.
- Nephrolepis exaltata can be propagated by division. If a pup forms on the side of the mother plant, you can choose to unpot the plant and carefully pull the roots of the pup from the mother plant. More often than not, however, a pup will not form and this plant’s centralized structure will not allow for division. Avoid propagating Nephrolepis exaltata under these conditions.
- Because these plants like moisture and high humidity, gray mold and other types of fungal infections are a concern. Prune away any unhealthy fronds and treat with a fungicide for plants. If mold is found in the soil, prune away any affected roots and repot the plant in a clean pot using fresh soil.
- Aphids, mealy bugs, and scale are attracted to these plants. To treat, wipe leaves with rubbing alcohol or diluted neem oil.
- If infestation is especially bad, washing the foliage with a gentle soap is known to be effective. Be sure to rinse thoroughly.
Maintenance (pruning, legginess, repotting)
- Repot when the plant is rootbound, and only during the spring and summer. These will do best in a plastic or glazed clay pot. Unglazed clay wicks away moisture and leaves the soil prone to dryness.
- Even in the most ideal conditions, lower fronds will brown and eventually die. Pruning these away will allow the plant to dedicate energy to producing new growth.
- Nephrolepis exaltata are non-toxic to both pets and humans.