Boston fern, sometimes known as sword fern or by its scientific name, Nephrolepis exaltata, grows natively in North American woodlands. Hardy in zones 8 through 11, this tropical fern requires warm temperatures to thrive outdoors. Gardeners in most of the United States grow Boston fern exclusively as a houseplant or container plant brought indoors over the winter. Valued for its attractive, graceful fronds and ease of care, Boston fern creates a tropical splash in any indoor or outdoor garden.
Plant Boston fern in a medium-sized container filled with a growing medium made of one part peat moss and two parts potting soil to provide adequate drainage and fertility. Keep the plant in a location that receives low, indirect light throughout the day.
Maintain a temperature of 65 to 70 degrees F during the day and 55 to 60 degrees F at night for optimal growth. Never allow the temperature to drop below 50 degrees F or rise above 75 degrees F, or the plant will suffer.
Water Boston fern once every 10 days, allowing the soil to dry slightly between applications. Decrease watering frequency during winter to once every two weeks. Never allow standing water to accumulate, or the fern's roots will rot.
Mist once every two to three days with a spray bottle filled with tepid water to increase the relative humidity and clean dust from the leaves. Spray during the early morning so excess water is no longer present when temperatures drop in the evening.
Feed Boston fern once every four to six weeks during spring, summer and fall. Apply a houseplant fertilizer at the rate described by the manufacturer's directions for the best results. Water after applying to release the nutrients into the soil.
Repot the fern once every three years to provide additional room for growth and to freshen the growing medium. Increase the size of the container by 2 to 3 inches at each repotting and disturb the roots as little as possible while transplanting.