Skip to Content

Why Does My Boston Fern Smell? (Possible Problems+Fix)

Boston Ferns are a fabulous houseplant, popular throughout the world for their distinct evergreen fronds. However, one of the problems fern owners often have with their Boston fern is a pungent smell coming from their ferns which is a sign of a problem brewing in the plant’s soil.

The Boston fern generally smells due to bacterial growth in the soil of the Boston fern. Overwatering, root rot, pest infestations, wrong potting soil, and poor airflow can lead to a smelly Boston fern. Providing the Boston fern with the right growing conditions can help prevent this.

This article will discuss the various issues associated with the problem and suggest ways to prevent this problem. Let us keep reading to know more.

Boston fern 13

I have done my best to address all of your concerns in the article below. However, if you still have any questions or are confused about the article, you can receive personalized one-on-one assistance from me by leaving a comment below. I will respond to your comment within a few hours.

Please note: Simplify Plants is reader-supported. Some links in the post are affiliate links and I get a commission from purchases made through links in the post.

What causes Boston fern to smell?

Generally, fresh soil will give an earthy scent that feels refreshing and tied to nature.

However, if an obnoxious odor starts coming from the soil, you have to be alert because, in that case, something is not quite right with your Boston fern.

Usually, this smell comes due to bacterial growth in the soil.

The smell coming from your Boston fern soil can cause concern if not corrected.

In most cases, the culprit of this problem is the lack of oxygen in the soil. 

This leads to the growth of harmful pathogens and fungus in the soil, which occurs due to various reasons, among which overwatering is the most common.

When the soil begins to have too much water constantly, the air pockets in the soil that allows air circulation begins to get blocked.

This creates a condition for the roots where they can no longer thrive, leading to the growth of harmful bacteria and pathogens in the soil.

This can make pathogens thrive in the soil, which can cut the life of the Boston fern and kill it.

Let us read about a few common causes that can lead to a smelly Boston fern.


Boston fern watering

The most common reason that kills plants is overwatering.

Soil saturated with water lowers the oxygen level in the soil, making it a spot for pathogens to breed, which leads to smelly toxic soil.

Poor soil quality

Boston ferns require light well-draining soil.

If the soil used is too heavy and compact, this will not let excess water pass and will begin to suffocate the roots.

This can lead to pathogens growing in the soil resulting in the plant’s smell

Also read: What Kind Of Soil For Boston Fern? (Ideal Soil Mix+How To Make)

Inadequate drainage of the pot

Boston fern drainage holes

Using pots without drainage holes is a major cause of soggy soil

Many plant owners put their plants in fancy pots without drainage holes which are highly harmful to your plant.

Also read: What Kind Of Pot Is Best For a Boston Fern? (Size, Material & More)

Not emptying the cache tray

A cache tray or a saucer placed under the pots to collect the excess water from the drainage hole is not always emptied.

We often forget to empty the excess water, and the saucer remains full.

This makes the bottom of the pot constantly wet, making the soil wet.

You can place the pot over a layer of pebbles in the tray; this lets the water drain off and does not make the soil stay soggy, and it also helps to increase the humidity, which Boston ferns love.  

Nonporous pots

It is most often recommended to use porous containers made of clay to grow your plants because they are permeable.

Porous pots let the oxygen flow into the soil, which plastic or ceramic pots do not allow.

So, if you are using nonporous pots for your Boston fern, it can lead to a lack of airflow in the soil and higher chances of overwatering.

Poor ventilation around the plant

Stagnant air around the plant reduces the evaporation rate, which keeps the soil soggy for a long time.

You should keep the Boston fern around plenty of air.

Sometimes keeping too many plants clustered together can reduce the airflow in the place. 

Root rot

Boston fern root bound and poor drainage

Root rot is one of the worst results of overwatering, and it is dangerous for the health of the Boston fern.

If found in the initial stage, it can be cured.

However, it might get tricky to save the Boston fern if it is noticed in the advanced stages.

You have to be alert to find root rot in the initial stages before it kills your plant.

You cannot reverse root rot, and if not checked, it spreads quickly, leading to the death of the plant.

Root rot begins when the roots of your pathogens attack the roots of your Boston fern.

A healthy plant will always have white and crisp roots, but the roots become brown and mushy when a plant has root rot.

Such roots can not absorb or send proper nutrients to the plant.

Some signs of root rot include:

The major viruses that cause this issue are Aphanomcyes, Fusarium, Pythium, and Phytophthora.

The only way to find root rot is to pull out the plant and check the roots.

If they look mushy and brown instead of fresh, you must immediately wash them, trim the dead roots, and repot the Boston fern in fresh soil.

Also read: Boston Fern Root Rot: Signs, Causes+Fix

Signs of bacterial growth in the Boston fern

Let’s understand the various signs that your Boston fern will show when bacterial growth and a foul smell in the soil.

Stunted growth 

The plant’s slow growth is an initial sign that will tell you that it is stressed. 

Changes in the leaves’ structure and color 

Boston fern turning yellow

As the important nutrients from the soil begin to leach, one of the first and foremost signs your Boston fern will show is the change in leaf color and health.

The leaves get yellow, brown, or black and wilt, droop, and curl.

They may also become mushy and get soft. 

Algae growth

You may notice that algae buildup has started to form on the soil’s surface, indicating microbial activity in the soil.  


Worms play an important role in the healthy growth of a plant.

They leave a nutrient-rich cast in the tunnels they create in the soil, which helps the roots grow favorably and penetrate deeper into the soil to get extra nutrients and moisture.

If many worms appear on the soil’s surface, you must understand that something is not right below the soil.

When they cannot survive in the toxic soil, they start coming up to the surface.

Weeds growth

This lack of oxygen creates an anaerobic environment underneath the soil’s surface that leads to the growth of weeds.

So if you suddenly notice your Boston fern is getting too full of weeds, you should check the soil for waterlogging and bacterial growth.

Water collection

Boston fern overwatering

Another sign to watch out for is waterlogging in the soil. You will notice that the water refuses to drain out and collects at the top of the soil.


If there is bacterial growth in your Boston fern, it will become prone to pest attacks. So you might notice them on the plant.

Treating your smelly Boston fern

Treating your smelly Boston fern is important to save it from further damage.

Let us discuss the various steps to follow to treat the smelly Boston fern:

Take the plant out of the pot and clean the roots

First, you need to clean the roots to remove all the dirt and fungus.

You have to take the plant out of the pot and wash the roots with water.

Once you have removed the soil, check the condition of the roots.

Make sure to wear gloves to protect your skin from harmful toxins.

Discard the soil as it contains all the bacteria and pathogens that were causing the foul smell in the first place.

Scrub the pot

It is advisable to use a fresh pot because the existing pot has already become highly infested with fungus.

However, you have to clean the existing pot very well if you cannot.

Prepare a soapy water solution and scrub the pot well with the solution.

Prepare a fresh soil and repot

Boston fern soil propagation

Now prepare a fresh potting mix to repot the Boston fern.

Use good quality potting soil and mix perlite and sand for drainage and compost to increase the nutrient value of the soil.

Add some worm castings to improve aeration in the soil mix.

Before repotting the Boston fern in this soil, you must prune the plant.

Begin by pruning off the brown, dead, decayed leaves and stems.

Then find out all the infested and rotten roots and cut them away. 

You can spray fungicide on the healthy roots.

Then repot the plant in the fresh soil.

Water the freshly repotted plant until it comes out of the drainage holes. 

Keep it in a shaded airy spot, and do not disturb the plant.

Let it recover, and don’t fertilize until you see new growth.

Also read: What Kind Of Soil For Boston Fern? (Ideal Soil Mix+How To Make)

How to prevent the Boston fern from smelling bad?

Now that you know how to fix a smelly Boston fern let’s understand how you can prevent it from happening again.

Use the correct watering technique.

Boston fern watering

Wrong watering leading to fungus is the primary cause of smelly plants, so the watering schedule must be correct.

Remember, Boston fern needs even moisture in the soil, but it hates soggy soil.

Right watering technique and schedule are most important to avoid and prevent smelly Boston ferns.

If you are unsure when to water your plant, use the finger test to understand.

Dip your finger in the soil, and if the soil sticks to your finger, do not water.

If it does not stick to the finger, you can water it.

Alternatively, you can use a moisture meter to check the moisture content of the soil before watering.

Do not follow the same watering pattern all year round.

In summers, your Boston fern would need more water than it needs in fall and winter.

Also read: How To Water Boston Fern? (How Often, How Much & More)

Check the drainage

Always use pots with drainage holes to let the excess water flow out.

Using pots without drainage holes causes the water to stay in the soil leading to soggy and smelly soil leading to root rot.

You must also empty the cache tray from time to time.

Soil structure

Choosing the correct soil for your Boston fern should be a priority.

The potting soil should retain moisture and should not remain soggy and wet.

If the soil is too heavy and compact, the roots will not get sufficient airflow and oxygen, leading to smelly and suffocated ferns.

To make the soil well-draining and light, you can add sand, bark, and perlite.

Add organic elements like compost to make the soil more fertile and rich. 

Peat moss helps the soil to retain moisture. 

Provide air circulation

Keep your Boston fern in an airy spot where it will receive enough air.

If you group the Boston fern to increase the humidity around it, it might not be getting proper airflow.

Therefore, you must find a better place where it will receive enough airflow.

Use porous pots

Boston fern pot types

Although this is not a must, you can use porous pots to prevent the bad smell from coming from the soil.

Keeping the Boston fern in terracotta pots keeps the soil and roots well aerated, allowing proper oxygen flow.

Porous pots also wick away the moisture faster, thus, preventing overwatering.

Tips for a healthy Boston fern

  • It is recommended to use rainwater or distilled water for your Boston fern to avoid salt buildups because tap water contains chlorine and other harmful chemicals.
  • Use a humidifier to keep the humidity levels above 50%. 
  • Examine the plant regularly to find any pest infestation at the initial stages.
  • Using Neem oil is a good way to repel bugs as chemical pesticides are harmful and too harsh for the delicate fronds of Boston fern.
  • Keeping the fern in a spot that receives indirect light and good airflow is important. Stagnant air is a major reason for smelly plants.
  • Fertilize your plant only in spring and early summers, not winter. 
  • Always empty the cache and saucers to avoid the chances of root rot.
  • Do not leave your fern outside in the harsh winter months. Frost can rot your plant and kill it.

Also read: How To Revive Boston Fern? (Saving An Almost Dead Plant)

Reference: University of FloridaThe University of Arkansas DivisionTexas A&M University SystemThe University of GeorgiaUniversity of New HampshireWikipediaThe Royal Horticultural Society.

Recommended Garden Supplies

Are you looking for a readymade indoor plant soil mix that you can open and pour? Check out rePotme. They offer a wide range of readymade soil premixes for all your indoor plants.

Sharing is caring!

Leave a comment

Your email address will not be published. Required fields are marked *