Ferns are an excellent choice for an indoor plant because they tolerate -- and can even thrive in -- low-light conditions. In most cases, ferns are a hardy plant that requires little maintenance. The appearance of brown spots on their fronds, however, signals a number of potential problems, most of which can be dealt with in just a few easy steps.
Humidity a Factor
Brown tips on ferns are often caused by low humidity in the home. This can be a challenge in the winter months when inside air is typically super-dried by furnaces. Boost the humidity around a fern by placing the potted plant in a tray filled with gravel. Pour water in the gravel tray and keep the water level at least 1/4 inch deep at all times. This will create some needed moisture around the perimeter of the fern.
Exposure to too much sunlight can cause some browning of the tips of a fern. Ideal light conditions for a fern are likely found on the north or east side of a home. If a fern must be placed by a south or west window, cover the window with a sheer curtain to negate some of the effects of the sun on the plant. If a sheer curtain isn't an option, position the fern away from the window in order to avoid being directly in the sunlight.
Ferns need a moist soil environment, but should not soak in standing water. Boston ferns, which are easily maintained and popular for indoor plants, should only be watered once the surface soil appears dry. If you are applying too much water, the plant will begin shedding its fronds.
The Purdue University Cooperative Extension discourages misting the plant as a solution to low humidity problems. Although misting the fronds will keep them free of dust, placing the pots over a gravel base filled with water takes less time and is more effective.