Boston fern, also known as sword fern, is a popular perennial houseplant valued for its long, graceful fronds and ease of care. Cold-hardy in USDA hardiness zones 8 through 11 only, growers typically cultivate the plant indoors in cooler regions. Outdoors, Boston fern makes a spectacular ground cover for shady areas of the garden. Because of its intolerance to cold, however, gardeners often grow the plant in containers for quick transport when temperatures drop. Nurseries around the country stock Boston fern as a container-grown plant to make cultivation easy.
Place Boston fern in an east- or north-facing window to provide partial direct sunlight throughout the day. Maintain a constant temperature of 65 to 70 degrees Fahrenheit during the day and 60 to 65 degrees Fahrenheit at night.
Mist Boston fern twice per day with a spray bottle to raise the relative humidity and emulate the plant's native environment. Fill the spray bottle with lukewarm water to minimize shock. Spray once in the early morning and again during mid-afternoon.
Water Boston fern plants once every five days to prevent the soil from drying out completely. Keep the soil consistently moist at all times, but not wet or soggy. Reduce the frequency of watering to once every 10 days during winter, when the plant is not actively growing.
Fertilize once per month during spring and summer using a balanced 10-10-10 NPK fertilizer. Water Boston fern both before and after applying the fertilizer to release nutrients into the soil and prevent root burn. Read the manufacturer's instructions for proper dosage.
Prune Boston fern once every two months to remove faded, diseased or damaged foliage. Cut off the fronds at soil level to encourage the growth of new fronds and to minimize damage to the plant.