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Why is my Fern Turning Brown? [Reasons & Fixes]

Is your Fern looking floppy, crispy, and turning devilishly brownish out of nowhere? The chances are it is under severe duress.

Generally, Fern turns brown mainly from the lack of moisture (under watering or less humidity). Still, sometimes excess heat, insufficient light, soggy soil, pests, and fungal infections may also invite browning.

The sudden change in foliage color is often accompanied by other telltale physical signs given below.

Why are the Leaves on My Fern Turning Brown? (Causes & Solutions)

Ferns are the oldest types of plants on Earth, found throughout wet rainforests to deserts.

However, the one you grow as a houseplant mostly hails from a wet, humid environment where they grow in the moist understories in forests.

Therefore, Ferns as houseplants require a moist and humid environment, filtered light, organic soil, and good air circulation to thrive.

Here are the reasons behind the Fern plant leaves turning brown and their solutions.

1. Lack of Moisture

Ferns are moisture-loving plants requiring ample air and soil moisture to stay healthy.

When the Fern has enough moisture, its system can function properly and transport water and nutrients to all parts of the plant via tubes called the xylem and phloem.

Therefore, the lack of moisture, primarily from under-watering, will cause browning fronds in Fern plants.

Birds Nest Fern with brown leaves
Lack of moisture is the main cause of frond browning in Fern.

You can tell it by the tips or edges of fronds that begin turning yellowish, then gradually turning brown or even black in the Fern.

As the browning progresses, the affected fronds may wilt and become crispy or dry to the touch.

Quick Steps to Take

  • Start pruning off excessively browned fronds to prevent the Fern from expending energy on them.
  • If the Fern is severely dehydrated, soak the entire plant in water for a few hours to rehydrate it.
  • Place the entire pot in a water container or shower it with water.
  • It may be helpful to increase humidity levels around the plant by placing a humidifier nearby.
  • Move it to a more suitable location with less direct sunlight and better air circulation.

Preventive Measures

  • Water only when the top 1-2 inches of soil feels dry to the touch.
  • Provide an inch of water every 4-5 days in summer and every 7-10 days in winter.
  • Water thoroughly, ensuring that the water penetrates the soil and doesn’t just sit on top.
Pro Tip: Avoid letting the soil dry out completely, which can cause the fronds to brown and wilt.

2. Low Humidity

Low humidity can harm Fern plants, as they naturally thrive in high-humidity environments.

When Ferns are exposed to low humidity, their fronds can dry and crispy. The gradual dryness will cause the tips or edges of the fronds to turn brown.

The severe conditions may even invite stunted growth, leaf drop, and pest infestation without treatment, as its immunity is compromised.

So, it may be essential to increase humidity levels around the plant at all times, except in winter.

Quick Steps to Take

  • Removing browned and dried fronds using a sterilized pruning shear or scissor.
  • Place the pot in a water container or above a pebble tray filled with water to boost the humidity level temporarily.
  • Closely inspect the plant for a week for signs of recovery (new growth or green and erect fronds).
  • If the plant fails to thrive, check for signs of bacterial infection by sliding out the roots.

Preventive Measures

  • Water the plant regularly and mist the leaves in summer to boost the relative humidity.
  • Remove the plant from direct sunlight to prevent the risk of excess transpiration.
  • Fertilize regularly during the growing season to boost its biomechanism.
Expert Tip: Install a room humidifier and maintain the humidity between 40 and 50%.

3. Overwatering Problem

Overwatering is the main culprit behind almost every major plant problem, including the leaves on Fern turning yellow and brown.

Similarly, overwatering the Ferns will make the soil soggy, where plant roots struggle to obtain water and nutrients.

Some of the early signs of overwatering include yellowing fronds and leaf dropping.

The fronds will turn soft or mushy and gradually change to a brown shade due incapacitation of roots.

Healthy fern frond
Healthy fern fronds will be upright and green in the shade.

Likewise, the plant sitting on too much water has been more susceptible to fungal infestation, often leading to root rot.

When the Fern’s immunity is compromised, it becomes more prone to pest infestation. Therefore, early treatment becomes even more crucial.

Quick Steps to Take

  • Start with pruning off browned and spent fronds and disposing of them quickly.
  • Immediately cut back on watering and let it rest in a warm, brightly lit location.
  • Closely inspect the plant for a week for signs of recovery.
  • If not, slide out the plant to check for root rot signs (browned, dark, or mushy).
  • Prune off the damaged roots, apply fungicide, and repot in fresh, well-draining soil.

Preventive Measures

  • Once the Fern has recovered, adjust the watering frequency to ensure the soil can dry out partially between watering.
  • Ensure the plant gets adequate air circulation to dry out excess moisture.
  • Ensure the Fern is watered only when the top 1-2 inches of soil is dry to the touch.

4. Sunlight Issue

Ferns naturally thrive in medium to bright filtered or diffused light for at least 12-16 hours daily.

The Fern plant exposed to too much bright or direct light will witness scorched or browned leaves due to excess transpiration and sunscalding.

It will also wilt or become stunted, and the fronds will develop a bleached appearance or become crisp and dry to the touch.

Similarly, Ferns are inappropriate for low-lit environments as they mess with photosynthesis.

The plant may also begin to drop leaves or become leggy as it stretches toward the light. You would usually witness pale or yellowish fronds.

Quick Steps to Take

  • If the Fern receives too much direct sunlight, move it to a location with filtered or diffused light. Otherwise, move it to a brighter place.
  • For Ferns with scorched or browned fronds from too much sunlight, trim them off with clean scissors or pruning shears.
  • Keep an eye on the Fern to see how it responds to the new lighting conditions, which may take at least a week or two.
  • Fern exposed to too much light is likely to dry out. Check the soil moisture and adjust watering as needed.

Preventive Measures

  • Provide plants with around 4 hours of light daily (morning, mid or afternoon). 
  • Avoid exposing Ferns to direct sunlight, which can scorch the fronds.
  • Ensure that they receive a period of darkness for rest and recovery.
  • Provide a room humidifier or place a tray of water near the plant to help it recover from sun damage.
  • Keep them under LED grow light for at least 12 hours if sunlight is scarce in your region.
Lighting Tip: If you own Asparagus Fern, place it near an east-facing window with 4-6 hours of bright indirect sunlight daily.

5. Nutrient Deficiency

If your Fern is not receiving adequate nutrients, it may develop brown spots or yellow on its fronds.

These three are the leading causes of nutrient deficiency in Fern plants.

  • Poor soil quality
  • Lack of fertilizer
  • pH imbalance

The plant suffering from nutrient deficiency fails to produce enough chlorophyll for photosynthesis.

Without enough chlorophyll, the leaves may turn brown or yellow and die off.

Similarly, soil with zero organic matter and the wrong pH level can also affect the plant’s ability to absorb nutrients.

Quick Steps to Take

  • Start with trimming affected fronds to redirect the energy towards healthy growth.
  • Consider repotting and transplanting Ferns in a fresh, organic soil mix if the substrate is old or high on the pH scale.
  • Choose a balanced 10-10-10 water-soluble fertilizer, or look for one specially labeled for Ferns.
  • Mix the solution to half-strength with water, apply directly over the soil, and water thoroughly.

Preventive Measures

  • Regular fertilization with a balanced, organic fertilizer is a must.
  • Fertilize the Ferns every 4-6 weeks in spring and summer, and cut back in the fall and winter.
  • Change the soil every two years with a well-draining soil mix rich in organic matter that naturally contains a slightly acidic pH.

6. Fungal Disease

Ferns are susceptible to fungal infections, which can induce the leaves on Fern turning brown and yellow.

Plants grown in excessively moist or humid conditions, soggy soil, and low light are prone to fungal infections.

This can be caused by too much moisture, poor air circulation, or infected soil.

Fungal infections in Ferns are typically caused by a variety of fungi, including:

RhizoctoniaIt causes brown lesions on the fern fronds.
PythiumIt likely invites root rot and change in frond color.
PhytophthoraIt induces yellowing and wilting of the fronds.
FusariumIt causes browning and wilting of the fronds.

These fungi can enter the plant through the soil, water, or air and can cause various symptoms, including yellowing or browning of the fronds, wilting, and stunted growth.

Otherwise, check out for signs of infection, including dark or discolored spots on the fronds or a black, mushy appearance of the roots.

Quick Steps to Take

  • It is essential to act quickly to prevent the rampant spread if you suspect your Fern plant has a fungal infection. 
  • Remove any infected fronds using a sterilized pruning shear or scissor
  • Treat the plant with a fungicide. Choose copper fungicides, Chlorothalonil, and Thiophanate-methyl.

Preventive Measures

  • Provide adequate space around the plant to circulate air and prevent moisture buildup.
  • Use containers with enough drainage holes to prevent water from accumulating in the soil.
  • Use a room humidifier to adjust the humidity level appropriate for Fern plants.
  • Dispose of dead or dying fronds, and clean the leaves regularly with a damp cloth to prevent dust buildup.

7. Pest Infestation

Like any other houseplant, Fern is equally susceptible to common sap-sucking pests.

The sickly plants, or those left in low humid conditions, are more likely to attract pests like mealybugs, scale, spider mites, thrips, and aphids.

Pests to Attack Ferns
Common pests appear on the fronds or in the soil.

Some of the common signs of pest infestation include:

  • Leaves on Fern turning brown.
  • Stunted growth.
  • Wilting or drooping fronds.
  • Presence of sticky residue on the fronds or soil.
  • The visible presence of insects on the plant or in the soil.

Quick Steps to Take

  • Start with removing affected fronds using a pruning shear.
  • Pick visible pests from the plants and drop them in a warm soapy water mix.
  • In any case, spray the plant with insecticidal soap to kill and repel insects instantly.
  • Alternatively, applying a solution of neem oil or horticultural oil to the plant will kill and repel pests.

Preventive Measures

  • Regular inspection and good cultural practices are a must.
  • Groom the plant regularly by trimming browned, decayed, and spent leaves.
  • Dispose of drained water from the cachepot.
  • Fertilizer regularly during the growing season with balanced plant food to boost the plant’s immunity.

Does your Boston Fern look sickly? Find out the top reasons behind your Boston Fern dying.

From Editorial Team


Ferns, as houseplants, require a relatively stable environment miming their natural habitat of shaded and moist forest understories.

Therefore, ensure your Fern gets enough moisture, but not too much to stay healthy and thrive.

To keep it healthy, provide proper air ventilation, regular grooming, supplementary nutrients, and soil change every few years.