Why Is My Boston Fern Not Growing? (Causes+Fix)

Boston ferns are popular houseplants loved for their evergreen fronds. But it can be heartbreaking when your Boston ferns stop growing even after you give them proper care and attention.

Inappropriate lighting and incorrect watering methods are the primary causes of stunted growth in Boston ferns. Monitor your Boston fern for signs and provide adequate lighting, correct watering, ideal temperature, and humidity to encourage growth.

Read this article to learn about the various problems that can hinder the growth of your Boston ferns. Also, I will provide you with solutions to encourage their growth.

How fast do Boston ferns grow?

Boston ferns are considered slow growers.

They can take 5-7 years to reach maturity.

But their fronds grow rapidly throughout the growing season and form crowns within 2-3 weeks.

Boston ferns can grow up to 6 to 7 feet tall in their natural habitat.

But when grown in containers, they grow 2 to 3 feet tall.

However, the growth rate of a Boston fern plant will depend on the light, water, temperature, and humidity it receives.

If they receive optimum growing conditions, they can reach up to 3 to 4 feet.

The ferns will keep growing well if you provide them with all their ideal growth requirements and assess whether they are experiencing any problems or not.

If you notice that they are growing slower than their actual speed, something is wrong.

You need to identify the cause behind their slow growth and solve it as early as possible.

Also read: How Fast Does Boston Fern Grow? (+Boston Growth Rate)

Why is the Boston fern not growing?

You may think you are doing the right things for your Boston fern, but somewhere something is wrong due to which your plant has stopped growing.

The plant can restrict its growth if it is pest-infested or not getting enough care from its owner.

If you can figure out what’s wrong with your plant, you can fix the problem.

Now, let’s look at all the factors responsible for no growth in your Boston fern plant.

Dormant season

Boston ferns grow actively during the spring and summer season as it is their growing seasons.

They usually don’t show any growth during the winter season as they remain dormant.

This is because the winter season comes with low temperatures that are unfavorable for the growth of Boston ferns.

So instead of growing, they try to save their energy and focus more on surviving winters.

You may not notice any growth in Boston ferns during winters.

Also read:

• Can Boston Fern Survive Winter Indoors? (+Winter Care & Dormancy)
• Boston Fern Temperature Tolerance: +Ideal Temperature

Overwatering

Overwatering is one of the major causes of stunted growth in Boston ferns.

They prefer to grow in soil that remains moist and not soggy. 

When you overwater the plant, the soil doesn’t get a chance to dry out, due to which the roots remain consistently wet.

The oxygen level in the soil reduces.

As a result, the roots fail to breathe and get suffocated. 

The roots become weak and fail to transfer water and nutrients to the plant, resulting in yellow leaves and stunted growth.

Prolonged overwatering will result in root rot disease, which causes the roots to decay and die. 

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

Underwatering

Boston fern likes to grow in well-hydrated soil.

If you do not provide the plant with enough water, it will become dehydrated. 

The roots get dry and fail to provide water and nutrients to the plant, due to which the plant will fail to carry out life processes and will stop growing.

Along with stunted growth, the plant will show other signs of underwatering such as wilting, yellowing, crispy, and dry leaves.

Inappropriate lighting

Understanding the light requirements of Boston ferns is important for maintaining their healthy growth.

They come from tropical rainforests, where they are adapted to get bright, indirect light through the canopy of the trees.

And so, these plants will stop their growth if kept in a shaded location.

If Boston ferns don’t get the required amount of light, they will not be able to perform photosynthesis, resulting in stunted growth.

Low light will increase the chance of overwatering and make the plant more susceptible to pests and diseases. 

Boston ferns will also stop growing if exposed to direct sunlight.

Prolonged exposure to direct sun will cause the ferns to lose excess moisture from the leaves, due to which they will dry out, become weak, and stop growing.

Direct sunlight will scorch the leaves and cause the fronds to be brown at the tips and edges.

Also read: What Kind Of Lighting Does A Boston Fern Need?

Wrong soil mix and pot

Boston ferns prefer to grow in potting soil that can hold enough moisture for the plant but drain out the excess water through the drainage holes. 

If the soil is too dense, it will hold more moisture, increasing the chances of overwatering.

On the other hand, if the soil is too loose, it won’t be able to hold sufficient moisture needed for the plant’s growth.

Therefore, you must select the correct soil type for your plant to avoid such problems. 

Also, the pot you are using should match the size of your Boston fern.

If the pot is too big, it will cause an overwatering situation.

And if the pot is too small, it will suffocate your plant’s roots.

Also, the pot should not lack drainage holes to drain the excess water. 

Otherwise, the plant will suffer from root rot.

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

Temperature stress

Boston ferns like to stay in warm temperatures between 60-75°F.

They cannot withstand freezing temperatures, and whenever the temperature goes low, the plant faces growth problems.

If the plant is exposed to low temperatures for too long or experiences temperature fluctuations, it will get stressed and show symptoms like: 

• Droopy leaves
• Discolored leaves
• Stunted growth

Also read: Boston Fern Temperature Tolerance: +Ideal Temperature

Improper fertilization

Boston ferns get nutrients from the soil, and over time the soil becomes old and loses all its nutrients.

So fertilization is important for providing the absent nutrients to the plant.

If the fern doesn’t get the required nutrients, it will weaken and stop growing.

Other signs of under-fertilization include scanty leaves, weak stems, and discolored leaves.

Similarly, over-fertilization will also harm your plant’s growth.

The excess salts from the fertilizer will accumulate on the soil surface, which will absorb all the moisture, causing the plant to have damaged roots and yellow leaves.

Also read: Should I Fertilize My Boston Fern? (Ideal Fertilizer+When & How Much)

Pest infestation

Pests like mealybugs, thrips, caterpillars, and scales can attack your Boston fern if exposed to unfavorable environments for too long.

The pest attacks the plant in damp, warm, and humid conditions.

The pests suck the plant’s sap, which contains the nutrients it needs to grow.

Without it, the plant will become weak and lifeless and eventually stop growing.

If the pest remains unnoticed, they can even kill your plant since they rapidly populate.

If your Boston fern has stopped growing, you must check on the underside o the leaves for pest infestations. 

Also read: Boston Fern Pests And Diseases: Common Bugs & Diseases+How To Fix

Low humidity

Boston ferns are tropical plants, and thus they thrive in high humid conditions.

In their native places, they receive high humidity.

However, the humidity level indoors is comparatively low for fern growth. 

Boston ferns will stop their growth if humidity falls below 50%.

Also, the dry air will cause their foliage to curl up and turn brown.

Also read:  Should I Mist My Boston Fern? (How Often+Pros & Cons)

Fungal infections

Another severe issue that can damage your Boston fern is fungal diseases.

Boston ferns are prone to diseases like Pythium root rot and Rhizoctonia aerial blight. 

The diseases attack your plant in unfavorable growing conditions.

You might notice signs like discolored leaves, brown spots, holes on leaves, mushy and black roots, etc.

The diseases will stress the plant and will slow down its growth rate.  

How to encourage growth in Boston ferns?

You can encourage growth in your Boston fern by providing it with proper care and required growing conditions.

The plant will continue to grow at its usual speed without being disturbed by unfavorable conditions with proper care.

Let us now discuss how you can follow to encourage Boston fern’s growth.

Give sufficient light

Boston ferns need at least 3 hours of indirect light every day to thrive.

If the light intensity is low, you can provide them with extra hours of light. 

A north-facing window is the best place to keep Boston fern.

The light intensity in this area is low, ideal for your plant.

Keep the plant away from the south or west-facing window, as this window has the strongest light intensity that can harm your plant.

If you do not have a north-facing window, you can keep your Boston fern near any window with some protection.

You can cover the windows with sheer curtains to filter the direct light.

Or, you can keep your plant 6 to 10 feet away from the window to save it from the intense light.

Rotate your plant twice a week to provide light on all its sides.

If natural light is insufficient, you can use artificial light to grow your Boston ferns.

Maintain proper watering routine 

Boston ferns will require watering every week during their growing season.

In general, you should keep the soil slightly moist.

Check the moisture level by inserting a finger into the soil or using a moisture meter.

Water the plant only when the top 2 inches of the soil feels dry to touch.

Whenever you water your Boston fern, allow the soil to soak up entirely from top to bottom.

Never let the soil dry out completely, as it can kill the plant.

Avoid overwatering your Boston fern, resulting in root rot, pests, and other fungal diseases.

If, by any chance, you have overwatered your plant, then stop watering it for a few days and keep it in a bright spot to let the soil dry.

If the plant is not recovering, take it out from the pot and inspect its roots. 

If it has root rot, prune the infected roots and repot the plant in a new pot and fresh potting mix.

Provide sufficient fertilizer

Boston ferns need an adequate amount of fertilizers to ensure proper growth.

The fertilizer should have a nitrogen, potassium, and phosphorous balance.

The ideal NPK ratio for Boston ferns is 20-10-20.

To fertilize your Boston fern, you can use water-soluble liquid fertilizer or slow-release granules.

Usually, liquid fertilizers are more suitable since they are easy to dilute and reduce the risk of overfertilization.

Avoid fertilizing the plant during the winter season as the plant goes into dormancy and does not need fertilizers for growth.

If you have overfertilized your plant, give a good wash to the soil by watering it thoroughly.

Wash the soil a few times to remove the fertilizers completely.

You can also repot the plant in a fresh potting mix.

Maintain the ideal temperatures

Boston ferns thrive in warm to average temperatures.

To encourage growth, maintain temperatures between 60-75°F.

They also like gradual decrease in temperatures during the nighttime. 

It will work great on your plant’s foliage if you maintain this balance. 

Make sure never to let the temperature fall below 40-50°F.

You can use a hygrometer device to check temperatures along with the humidity.

It will help to know whether your plant is getting the ideal temperature or not.

Keep your Boston fern away from heating or cooling devices such as radiators, heaters, air conditioners, and gas burners.

During the winter season, protect the plant from low temperatures and frosty locations.

Ensure sufficient humidity

Boston fern needs high humidity levels to thrive.

You should try to maintain a humidity level above 50% for growing them. 

You can mist your Boston fern regularly with a spray bottle during the growing season to keep it moisturized.

However, misting is not much of a practical idea as it can encourage pests and diseases to the plant.

A better way to increase humidity is by grouping Boston fern with other moisture-loving houseplants.

But the best way to maintain the ideal humidity around the plant is by using a humidifier.

Select the correct potting mix and pot

To encourage the healthy growth of Boston ferns, use a potting mix that is well-draining and well-aerated.

Also, the potting mix should be rich in essential nutrients.

You can prepare the ideal potting mix by mixing potting soil, perlite, coco coir, and orchid bark.

Make sure the potting mix should be acidic with a pH level of 6.0 to 6.5.

The pot for growing Boston ferns should be 2 inches larger than the plant’s size.

This will provide enough space for the roots to grow.

Use a glazed terracotta or plastic pot for growing ferns.

The pots will keep the soil moist as they take longer to dry out.

But be careful as these pots can cause overwatering if you water too frequently.

Treatment against pests 

If you have a pest-infested Boston fern plant, try to remove them as soon as possible.

To remove pests, consider these:

• Give your Boston fern a good shower with a strong freshwater spray. After washing, leave the plant in a bright spot to let it dry.
• Wear gloves and handpick all the visible pests.
• Dip cotton swabs in rubbing alcohol solution and wipe off the infested areas.
• Spray Neem oil or horticulture oil sprays over the plant every week until the pest goes away.
• Prune off all the infected and damaged leaves with sharp and sterilized pruners to relieve stress.

Treatment against disease

If you think your Boston fern is undergoing any fungal disease, spray the plant with a copper fungicide solution.

Prune off the dead and decayed leaves and parts from the plant.

To treat Blight fungus, use a fungicide that contains methyl compounds. 

You can also drench the soil with the same fungicide to kill the pathogens. 

If the soil condition is poor, repot the plant in a fresh potting mix and new pot.

Avoid overwatering the plant, and don’t expose it to very low temperatures.

Seasonal care

During the winter season, the plant care routine will change.

Reduce watering during the autumn and winters as Boston ferns slow down their growth during this time. 

Water the plant every 1 to 2 weeks to prevent overwatering.

But never let the soil dry out completely.

Also, avoid fertilizing the plant as Boston ferns don’t need fertilizers during their dormant season.

During winters, you can keep the plant outside for a few hours in the morning time when light levels are low.

Final thoughts

There can be many reasons that stop your Boston fern’s growth.

Do not worry if you find slow or stunted growth in your plant. Try to figure out what problem your Boston fern is facing and then fix it as per the methods I mentioned in this article.

The key to keeping your Boson fern happy is providing it with ideal growing conditions. Ensure that the plant receives proper light, water, humidity, and temperature.

Do not panic if your Boston fern does not show growth during winters as they take rest during that time. The plant will start growing again during the spring and summer seasons.

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Reference: University of Florida, The University of Arkansas Division, Texas A&M University System, The University of Georgia, University of New Hampshire, Wikipedia, The Royal Horticultural Society.