Where to Plant Boston Fern
In hardiness zones 9 to 11, Boston ferns can be grown as perennials as long as they receive plenty of water. These lush ferns do not tolerate drought and need full or partial shade with protection from drying winds. Covered patios are a good location for growing them in warmer climates.
Outside zones 9 to 11, Boston ferns are better suited to containers. Container-grown plants can be brought indoors when temperatures drop below 45°F.
Indoor Boston ferns thrive in bright, indirect light and high humidity. Place them near a north- or east-facing window, preferably in a naturally humid room.
Avoid placing Boston ferns near heaters, vents, or radiators because dry air and sudden temperature changes can stress the plant.
When and How to Plant Boston Fern
For outdoor planting, spring or fall is ideal when temperatures are milder. Indoor Boston ferns can be planted at any time.
Choose a shady location with moist, well-draining soil. Dig a hole about as deep and twice as wide as the nursery pot. Place the fern in the hole and backfill with soil mixed with organic compost.
Adding mulch around the base can help retain moisture and increase humidity.
For indoor planting, choose a container with good drainage and fill it with a rich, well-draining potting mix that retains moisture without becoming soggy. Plastic or glazed ceramic pots can help retain moisture around the roots.
Before acquiring a new plant, make sure your environment meets its needs. Not every plant will do well in every location.
Boston Fern Care
Boston ferns are relatively easy to grow when their three main requirements—moisture, light, and humidity—are maintained.
Outdoors, they prefer shade and consistent watering. Indoors, they need indirect light and a humid environment.
Light
Indoor Boston ferns prefer bright, indirect light, such as near an east-facing window. Turn the pot occasionally to encourage even growth.
Too little light can cause the fronds to become dull and sparse, while too much direct sunlight can burn the fronds.
When grown outdoors, protect Boston ferns from direct sunlight and strong winds.
Soil and Water
Boston ferns prefer moist, well-draining soil with a neutral to slightly acidic pH of around 5 to 5.5.
A peat-based, soil-based mixture works well when kept consistently moist. If the soil dries out, the fronds may turn brown and fall.
If tap water contains high levels of chlorine or fluoride, filtered or rainwater can be used because Boston ferns are sensitive to chemical buildup.
Temperature and Humidity
Boston ferns grow well indoors at temperatures between 60°F and 75°F.
Humidity is especially important. Ideally, humidity should be above 80%.
Regular misting or placing the plant on a tray of gravel or pebbles can help increase humidity around the plant without making the soil excessively wet.
Fertilizer
Boston ferns benefit from regular feeding during the growing season.
Use a water-soluble fertilizer every 4–6 weeks during spring and summer. Fertilization is generally not necessary during fall and winter.
For potted ferns, a houseplant fertilizer at half strength can be applied about once a month from spring to early fall.
Pruning
If the fronds dry out and fall, leaving bare stems, cut the Boston fern back to about 2 inches in spring. The plant can then regenerate new, lush growth.
Spring is also a good time to divide the plant.
Potting and Repotting
When planting a young Boston fern, choose a container that is only slightly larger than the root system.
An excessively large pot can cause the plant to focus on root growth rather than foliage and can also increase the risk of root rot.
Use a peat-based potting mix with perlite for good aeration. Place the fern in the container, fill around the roots without compacting the soil, and water thoroughly.
Boston ferns commonly become root-bound. Before repotting or dividing an established plant, water it well to make the root ball easier to handle. Remove the plant carefully from its container and loosen or divide the root ball as needed.
Pests and Problems
Outdoor Boston ferns can be affected by mealybugs, spider mites, and whiteflies. Snails, slugs, and caterpillars may also feed on the foliage.
Both indoor and outdoor plants can develop blight and root rot.
Blight may appear as dark brown spots on the foliage, crown, or roots. If it occurs in a container, repot the plant using a sterilized container and fresh potting mix.
Root rot usually develops when the soil remains excessively wet for too long. For container plants, remove the plant, discard the diseased soil, and repot it in a sterile container.
For outdoor plants, improve soil drainage or divide the plant and replant healthy sections in a better location.
Propagation
One of the best ways to propagate Boston ferns is through division, preferably in spring.
- Remove the root ball from the soil.
- Divide it into 2–4 sections, keeping as many healthy leaves as possible on each section.
- Replant the divided sections.
- Water thoroughly after planting.
Regular division also helps prevent the fern from becoming excessively root-bound.
Types of Boston Fern
Boston ferns are available in green and variegated forms, with curly, wavy, twisted, drooping, and overlapping fronds. Some varieties have finely divided leaflets that create a loose, airy appearance.
Boston Fern
Nephrolepis exaltata 'Bostoniensis' is the most common Boston fern cultivar. It has elegant, arching fronds and is hardy in USDA zones 9–11.
'Dallas' Fern
This variety of Nephrolepis exaltata tolerates lower light and drier air better than the common Boston fern. It is compact, with fronds about half the length of those of traditional Boston fern.
'Fluffy Ruffles' Fern
This compact form of Nephrolepis exaltata has finely divided, overlapping fronds and ruffled leaflets. It is hardy in zones 9–11 and does not produce spores.
'Kimberly Queen' Fern
Nephrolepis obliterata 'Kimberly Queen' is native to Australia and closely related to Boston fern. It has large, upright fronds and is less sensitive to low humidity.
It is also more tolerant of direct sunlight but should still be protected from harsh afternoon sun.
Tiger Fern
Tiger Fern is a variegated Boston fern with irregularly marbled gold-and-green foliage. It is hardy in zones 10–11 and develops large fronds that grow upright before arching with age.
'Rita's Gold' Fern
Nephrolepis exaltata 'Rita's Gold' has bright chartreuse-yellow foliage, especially on new growth. It is hardy in zones 9–11.
Companion Plants for Boston Fern
Boston ferns prefer shady, moist growing conditions, so their companion plants should have similar requirements.
Bleeding Heart
Bleeding heart plants thrive in shady woodland conditions similar to those preferred by Boston fern. Choose varieties that can tolerate warmer climates when planting them together.
Browallia
Browallia prefers full to partial shade and moist, well-draining soil. Its blue, purple, or white flowers provide a colorful contrast to the green foliage of Boston fern.
Caladium
Caladium grows well in dappled shade and provides colorful foliage without exposure to harsh direct sunlight.
Impatiens
Impatiens are shade-loving flowering plants that work well as fillers in garden beds. They prefer rich, well-drained soil and can provide flowers in shades of blue, orange, pink, purple, red, white, and yellow.
Frequently Asked Questions
How did the Boston fern get its name?
The Boston fern was discovered among a shipment of plants sent from Philadelphia to a florist in Boston in the 1890s. The plant was later identified as Nephrolepis exaltata 'Bostoniensis'.
How do Boston ferns reproduce?
Boston ferns can reproduce through spores and runners called stolons. However, division is the best method for producing plants that closely match the parent plant.
Are Boston ferns toxic to pets?
Boston ferns are not toxic to dogs, cats, or humans. They can therefore be used safely around pets, although it is still best to prevent animals from damaging the plant.
