Can Air Conditioning Cause Ferns to Brown?

Location

• If possible, place your ferns in a humid location, such as a bathroom, basement, kitchen or laundry room. Do not place ferns next to air conditioners or heaters, as they will dry out the plants and cause brown foliage. Ferns vary in their light requirements, but most types grow best in indirect light, such as the light from a north-facing window or a window with a sheer curtain.

Increasing Humidity

• Ferns grow best in 40 to 50 percent humidity, according to the University of Georgia. You can raise humidity in several ways. For example, you can use a humidifier to add water to the air, but making your whole home too humid may encourage mildew growth or other problems. Misting ferns each morning, or placing a potted fern in another pot that contains water and gravel or sphagnum moss, will also raise humidity and prevent brown fronds. Replace the water or moss regularly to prevent mildew growth.

Watering

• Watering ferns properly also helps reduce the stress and damage caused by dry air. Ferns require regular watering, especially during the growing season. Depending on the size of the plant and the temperature and humidity of the air, you may have to water as frequently as every day or as little as once a week. If you water ferns too much or too little, they may become brown, look unhealthy or unattractive or shed fronds.

Considerations

• Insect problems may also cause ferns to turn brown or black. For example, the sticky honeydew excreted by fern scales and other pests often turns fronds brown or black as it grows fungus. Check ferns for insects once a week. Ferns may also dry out too quickly if they are placed in a location that receives direct light or if they are kept in a warm area. For best results, keep ferns in temperatures that are 72 degrees Fahrenheit or cooler during the day and 60 degrees F or cooler at night.