Boston fern, known botanically as Nephrolepis exaltata "Bostoniensis" is a tropical fern commonly grown as a patio, porch or indoor plant. According to the University of Rhode Island, "Bostoniensis" is a cultivar that demands high ambient humidity and consistently moist soil. Watering the soil is but one way that you will need to deliver moisture to your plant to keep it healthy. To prevent your fern from suffering browning leaf tips or frond die-back, vigilant care is needed, and the higher you can get the humidity around your Boston fern, the happier it will be.
Water the soil of your Boston fern consistently to keep it evenly very moist to the touch but not drowning in stagnant water. Unlike some ferns, Boston fern cannot tolerate its soil to be dry, even on the surface, between waterings. In hot and dry climes, daily watering may be required, while gardeners in cool, rainy climes can offer less frequent irrigation.
Boost the ambient humidity passively by setting the fern pot atop a shallow tray filled with stones or marbles and water. Keep the bottom of the pot above the water resting on the stones but refill the tray reservoir frequently to keep the water level high.
Mist your Boston fern frequently with a spray bottle filled with distilled water. In low humidity environs or when heating and cooling is being used, daily misting may help keep the fronds green. Refrain from misting with tap water as the treatment chemicals, salts and minerals in the water can damage the leaves.