How to Take Care of a Boston Fern With Brown Leaves

Boston fern plants require a delicate balance of water, humidity and light to maintain their graceful appearance. The oldest fronds on the Boston fern, also known as sword fern, naturally turn brown when newer fronds emerge in a mature plant. Remove these during regular house plant grooming and care routines. If the leaves on newer fronds brown, change conditions promptly to restore the beauty of this indoor plant.

Things You'll Need

• Scissors
• Fertilizer
• Tray
• Decorative flowerpot
• Pebbles
• Cotton swab
• Alcohol
• Insect spray

Instructions

1. Cut off the frond with brown leaves at its base with sharp scissors. If only the tip of the frond is affected, snip that section off, leaving the frond intact until the next time the Boston fern is transplanted.

2. Stop fertilizing the plant for at least one month. Resume fertilizing only when new fronds begin emerging or if the fern's color becomes pale and dull. Then use an all-purpose houseplant food or fish oil mixed to half the strength recommended on the manufacturer's label instructions.

3. Move the Boston fern to brighter light. Set or hang the plant where it will receive indirect sunlight, but not close enough to a window that it can be damaged by direct sun rays.

4. Adjust watering techniques. Do not water the fern until the top half-inch of the soil is dry to the touch. Place the Boston fern in a sink and add lukewarm water until it begins to drip out the bottom. Allow the plant to drain for an hour before returning it to its location.

5. Ensure the Boston fern has sufficient humidity. Set the fern on a 2-inch layer of pebbles in a tray or pie pan and keep 1 inch of water in the bottom of the tray. Alternatively, fill the bottom 2 inches of a larger size decorative flowerpot with pebbles, set the potted fern inside the decorative pot, and keep an inch of water on the pebbles.

6. Examine the plant for mites with a magnifying glass if the leaves continue to brown. Wipe away the pests with a cotton swab dipped in alcohol. Spray the entire plant lightly with an insecticide formulated for house plants.

Tips & Warnings

• Do not spray your Boston fern plant with water as the droplets may settle on the fronds and cause leaf spotting.

References

• Purdue Univ. Extension: Ferns for Indoors
• U of MN Extension: Growing Tropical Ferns Indoors

Resources

• Boston Fern fact sheet