Boston ferns (Nephrolepis exaltata) are humidity-loving plants that are most commonly grown as houseplants. Also called ladder or sword ferns, they have 10-inch to 3-foot-long, light-green, graceful fronds and are generally easy to care for. The only caveat to growing Boston ferns is that they demand high humidity and tend to drop their fronds when they're too dry. These ferns can grow quite large, but some dwarf varieties have been engineered to create more compact houseplants.
Place your Boston fern in indirect sunlight to low light, such as beside a north- or east-facing window, but not in direct sunlight. Maintain air temperatures around the Boston fern of 65 to 75 degrees F during the day and around 60 degrees at night.
Water your Boston fern three or four times per week to keep the soil evenly moist at all times. Provide water until it begins to drain from the bottom of the pot, and discard the excess water from the drainage dish.
Mist your Boston fern daily or once every two to three days with room-temperature water to increase humidity around the plant, especially during winter. You can also set the Boston fern's pot on top of a tray filled with pebbles and water, ensuring that the pot is sitting on top of the pebbles and not in the water.
Feed your Boston fern once each month from April through September with a liquid houseplant fertilizer at half the normal dosage rate. Wait to begin feeding newly potted Boston ferns for about four to six months, or until the fern begins to grow actively again.
Repot your Boston fern once every two or three years in the spring and divide any crowded plants. Pot the Boston fern in a container that has drainage holes in the bottom and that is the next size up, planting the fern in a soilless potting mix containing about 50 percent peat moss.