Boston fern plants, also known as sword ferns, perform best outdoors in USDA Hardiness Zones 9 through 11. In most of the United States, however, gardeners often grow the ferns indoors, where they perform well under normal household conditions. Boston fern's attractive, evergreen foliage keeps its color year-round, making it an ideal focal point for any room. The use of a hanging basket maximizes the appearance of the long, arching fronds. Widely considered one of the easiest ferns to grow indoors, the Boston fern requires only basic care once established.
Plant Boston fern in a medium-sized container filled with a growing medium made of one part potting soil and one part peat moss for optimal growth. Keep the plant in a location that receives partial shade each day, such as a north-facing window.
Maintain a consistent temperature of about 75 to 80 degrees Fahrenheit during the day and 65 to 70 degrees F at night. Keep a thermometer near the Boston fern to ensure the temperature does not leave this range. If it gets too hot or cold, the plant may sustain damage.
Fill a shallow tray with small pebbles and fill halfway with water, leaving the tops of the pebbles dry. Place the fern on top of the pebbles to increase the relative humidity of the surrounding air. Add additional water as often as necessary, but never allow the container to sit in water.
Water Boston fern plants once every five days during spring, summer and fall to keep the soil consistently moist. Decrease the watering frequency to once every week to 10 days during the winter months, when active growth ceases and the plant requires less moisture. Soak the soil until water drains from the bottom of the container at each application.
Feed the fern once a month during spring and summer using an all-purpose houseplant fertilizer. Read the manufacturer's directions for the proper application and dosage. Moisten the soil before feeding and water lightly afterward for best results.
Repot Boston fern during late winter once every one to two years, or whenever the plant grows too large for its current container. Increase the size of the new container by 1 to 2 inches in diameter and provide a fresh growing medium to ease the stress of transplanting and prevent shock.