Growing Ferns Indoors

High Humidity

Ferns need high levels of humidity in order to grow properly. Without this humidity, they can shrivel and become dry, and are more prone to disease. Don't worry, though; you can provide your ferns with the proper level of humidity without great effort. Consider placing your ferns in the bathroom, which has natural levels of higher humidity after baths and showers. If you'd rather keep your ferns in another room, you can place their pots on a dish of pebbles and water. The water from the pebbles will absorb into the air around the ferns to keep them healthy. Another option is to keep your plants near a home humidifier or place them in a glass terrarium. Giving your fern's leaves a good misting once every couple of days will also increase the humidity, as will a layer of sphagnum moss on top of the plant's soil.

Low Light

Though ferns do need light, they prefer shadier areas that receive indirect sunlight. Plan on keeping your ferns in a north- or east-facing window, as these receive less sunlight than south- or west-facing windows. Placing your fern in bright, direct sunlight will cause its leaves to scorch and yellow. However, don't place your fern in a room that lacks natural light entirely, as they do need some filtered sunlight.

Rich Soil

Ferns prefer moist, rich soil. Amend typical potting soil with compost or peat moss, and apply a layer of sphagnum moss on top of soil to improve water retention and humidity. Keep soil evenly moist at all times, but not wet. Overwatered soil can lead to root rot and disease. Only a few types of ferns, such as Brake and Holly ferns, will tolerate lower levels of water. Though they thrive in rich soil, ferns don't need to be fertilized often. Feed them monthly with a light application of fertilizer during the active growing season, which is April through September. Use one half of the recommended feeding for best results, as too much fertilizer will cause leaves to burn.

Care and Maintenance

Keep a close eye on your indoor ferns to determine their needs. Though it's uncommon for ferns to be affected by pests, they are occasionally attacked by mealybugs and spider mites. If at all possible, remove affected areas of the plant or pick the insects off. It's best not to revert to chemical insecticides, as these can harm the gentle leaves of a fern plant. Once every year or two, ferns will need to be repotted, as they don't grow well in a potbound environment. To repot ferns, choose a potting soil that contains at least half peat moss and a container that's at least two inches larger in diameter than the original. Be gentle when dividing roots and rhizomes.