Skip to Content

Why Is My Boston Fern Turning Light Green? (8 Causes+Fix)

A Boston fern is native to tropical forests with mild temperatures and high humidity. But a common problem that these plants undergo is that their leaves turn light green.

Fronds turning light green is normal if the leaves are young. However, if older leaves start turning light green, the reason can be pest infestations, too much or too little light, and incorrect humidity. Identifying the problem and providing the right care will help fix this.

In this article, I will discuss the various reasons that can make the fronds of Boston ferns go light green and the preventive measures that can cure this problem.

Boston fern turning light green

Some links in the post are affiliate links and I get a commission from purchases made through links in the post.

Why my Boston fern leaves are turning light green?

It is normal for the young leaves to have light green color in Boston ferns.

As they mature, their color tends to darken.

So if you notice new fronds with light green color in an otherwise healthy plant, you need not worry.

However, it can become worrisome if you find that multiple leaves are starting to turn light green.

This might not be a normal occurrence and can indicate a problem.

Let us discuss the various causes that lead to your ferns turning lighter shades of green.

Incorrect watering

Boston ferns require consistent watering and evenly moist soil.

A soil that is too dry or too wet can damage your ferns.

Too much moisture or dehydration can cause the fronds to turn light green, then yellow, and ultimately wilt and fall off.

If you correct the problem in the initial state when it starts to turn pale green, you can prevent further damage.

Ferns are tropical plants that love moist soil and cannot stand dry soil.

The watering schedule of your ferns depends on and varies as per the requirement of the weather.

Indoor plants get dry more quickly than outdoor ones.

Ferns face a common problem because plant owners tend to overwater them frequently, thinking that the ferns would like that, but it is not so.

Overwatering can damage the plant greatly and, if not checked, can kill your plant.

Fluctuating temperature

Unstable temperature ranges are major reasons why Boston fronds lose their color, and leaves start turning light green and yellow.

Being tropical plants, they require a steady mild temperature range between 65°F to 75°F.

Temperature above or below it can affect the growth of the Boston fern.

They cannot tolerate extremely cold weather and frost or withstand extreme heat.


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.


Humidity levels

Boston ferns require a massive amount of humidity, nearly 80%, for their flourishing growth.

Even if that is not attainable, humidity below 50% can make the fern sick and dry, and it will lose its bright green color due to not having enough humidity.

If the area you live in has dry air and low humidity, it can get tricky to save your Boston fern.

Thereby, you have to use ways to increase humidity artificially.

Low humidity will make your plant lose its color and look dry and wilted.

Insufficient light

Boston fern in low light

Incorrect lighting is one of the most common reasons that torment this plant and make it look light green.

It is important to remember that these plants cannot tolerate direct sunlight because they grow under the shades of massive trees in nature. 

Ferns do best under shade, and if it is suddenly exposed to too much light, their fronds might look slightly bleached or light green or yellow.

Extremely harsh light can turn the fronds of the Boston fern to lose their color and make the plant leaves burn.

Similarly, extremely low light can also affect its growth because the plant will not be able to photosynthesize efficiently, reducing the green color of the fronds.

Inaccurate fertilization

Fertilizers give the plants necessary nutrients and food, which the plant tends to lose over time due to constant watering and erosion.

However, Boston ferns being low feeders, face the problem of overfertilization too often.

This leads to the loss of the green color in the fronds.

This makes the plant weaker and becomes more prone to pest attack.

Some of the signs that your overfertilized Boston ferns may show are leaves looking light green and yellow, salt accumulation on the soil, stunted growth, etc. 

Under fertilization can also stop the growth of the Boston fern by not giving it enough nutrients to flourish, which can impact its capacity to photosynthesize.

It is advisable to only fertilize your fern twice a year with a balanced 20-10-20 NPK.

Repotting stress

Repotting is stressful for the plant, and many times if the plant does not adjust to the new surrounding efficiently, it starts showing signs of stress like wilting, losing its color, dropping leaves, and so on.

Choosing the wrong potting mix can also harm the ferns because they prefer light soils that it loose enough for airflow.

Pest infestation

Boston fern neem oil

Though Boston ferns are quite hardy, they are still prone to pest attacks, especially mealybugs, scales, spider mites, caterpillars, and thrips.

These nasty bugs seriously damage the plant by sucking the sap and nutrients that keep the plant healthy.

This interferes with photosynthesis and causes the fronds to lose their color and turn pale green.

Pest attacks can be easily gone unnoticed if not examined thoroughly.

They can make the plant limp and lose its glossy and bright green leaves. 

The fern will gradually start becoming weak and lifeless and can kill the plant if not cured in the initial stage.

Roots problem

Diseases in the plant’s roots are very difficult to notice because they remain invisible to the eyes.

These, if not cured, can kill and destroy your Boston ferns.

The plant often looks healthy from the top but gradually shows signs of wilting and discoloration.

You should take the Boston fern out of the pot and check the roots in such a situation.

If they are brown or black and are slimy and smell bad, that is a sign of root rot.

You must take the necessary actions. 

If the roots look coiled and wrapped up in a tight ball, your fern is rootbound, and you should repot the plant to a bigger pot.

How do you fix the light green leaves on Boston Ferns?

Once you identify the issue, you can work on it and take actions to fix it.

This will help the fronds of your Boston fern get their dark green color back.

Provide right water

Boston fern watering

Correct watering is one of the most important factors in growing any plant.

If the amount is too low or too high, your plant can get affected.

Light green leaves on your fern are a common sign indicating your fern needs water. 

Do not forget that your fern enjoys moist soil but not soggy soil.

If you are a beginner in growing plants or do not understand the right time to water your plant, always dip your finger in the soil and check the moisture level before watering.

If that soil sticks to your fingers, then do not water.

Water it only if you see that the soil is not sticking to the finger.

You can also use a moisture meter instead of getting your finger dirty.

Do not let the pot sit on the water as that might lead to soggy soil.

Always use pots with drainage holes, so the water flows out. 

Never use pots without drainage holes to plant your ferns because the excess water will not flow out and instead will stay locked in the soil, making it soggy, and giving rise to pathogens ad fungus in the soil.

This can lead to root rots that can damage and kill the plant.

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

Correct the humidity levels

Boston ferns thrive in 80% humidity in the wild.

A humidity level of below 50% can seriously harm your plant.

However, having such high humidity levels in our homes is not possible.

A lower humidity level can dehydrate the plant and rob it of its required amount of humidity.

If your home has extremely low humidity levels, there are multiple techniques to increase the humidity around your plants.

  • Misting is one of the simplest and cheapest ways to increase the humidity around your plant. It increases the humidity around, cleans the leaves, and helps prevent bugs. However, their result is short-lived, and the water evaporates quickly.
  • Using a humidifier is another effective and long-lasting way to boost humidity around the ferns. Purchase a good quality humidifier, fill it with distilled water, and place it near your plants.
  • Using pebble trays to raise the humidity is another effective way to increase humidity. Just fill a tray with pebbles and add some water to it. Put the pot on this layer of pebbles making sure the water does not directly touch the pot of the fern. As this water evaporates, it will help to increase the humidity level.
  • Grouping the plants is another popular way to increase the humidity of your ferns. 

Keep your fern away from vents, air conditioners, heaters, and so on because they suck up the moisture from your plants, making the air drier, leading to dehydrated ferns.

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

Boston fern humidifier


Repotting

Repotting gives your plant a great deal of shock, pushing it to lose its color and shine, making it light green and wilt.

Remember to repot your fern only in the growing season, which is early spring, when they are actively growing, to deal with the shock easily.

Do not disturb the fern too much after repotting, and let it relax and adjust to the new environment comfortably.

It may wilt after repotting, and the leaves may start appearing light green.

However, it should bounce back provided it gets the right conditions.

Remember to keep it away from direct sunlight and at a place where it gets good airflow and indirect light. 

Choosing light, well-draining soil to let the roots breathe is also important for the ferns.

Heavy soil is bad as it tends to suffocate the roots and holds a lot of water.

Also read: Do Boston Ferns Like To Be Root Bound? (+When To Repot)

Correct the lighting

Light plays a very important role that determining the color of the foliage.

The leaves can become pale green if the Boston fern gets too little light.

To prevent this problem, you have to give the fern the right amount of light.

If your Boston fern is not getting enough sunlight, you can use artificial lights.

Remember, your fern in nature grows under the shades of huge trees where it gets dappled light.

Hence you have to create such conditions in your home.

If outdoors, keep your plant under a bigger tree or on a patio where there is no direct sunlight or a spot with a shadow of bigger houses.

If your fern is kept indoors, keep it near an East-facing window or a bright North-facing spot.

You can give it 2-3 hours of mild morning sunlight in winters but not more than that.

Too much light can scorch the fronds, making them light green.

Therefore, keep your Boston fern away from direct sunlight.

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

Pest infestation

Pests and bugs are a nightmare for every plant owner.

These pests can suck the nutrients off your ferns and thrive as the plant may turn weaker and paler, ultimately dying.

Here are 2 ways to kill these bugs and make your plant healthy again.

  • Soap water: Mix a few tablespoons of mild soap or shampoo into a gallon of water and spray it on the infested plant. Marinate it for a few hours, then wash it with clean water.
  • Neem oil: It is an organic pesticide that repels all kinds of bugs because of its anti-bacterial properties. Mix 2 tbsp. Neem oil to 1 gallon of water and spray it well to your fern. Repeat this a few times until the bugs are gone. 

Ferns are easily susceptible to damage by harsh pesticides, so better to use these organic ways to kill the bugs.

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

Fertilize properly

Boston fern fertilizer

Overfertilization can burn your Boston fern.

Boston ferns are light feeders.

They do not need heavy feeding.

So feed them with a balanced 20-10-20 NPK twice a year.

Adding organic elements like compostpine bark, and perlite to the soil will help maintain a balanced pH level.

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

How to prevent Boston fern leaves from turning light green?

We have discussed all the probable causes of the Boston fronds turning light green and solutions to avoid this problem.

Let us quickly go through the ways to prevent this problem in brief:

  • Keep the Boston fern away from direct sunlight.
  • Give it bright but indirect light. Do not keep it in a place that gets low light.
  • Check to water. Do not overwater the ferns, leading to root rotting and fungus growth.
  • Give your ferns a lot of humidity. If the place has low humidity, you must use other ways to increase the humidity, like pebble trays and humidifiers
  • Try to use rainwater or distilled water instead of tap water for your Boston fern to reduce the chances of build-ups and salt accumulation. 

Final words

Boston ferns tend to show signs of stress very quickly, so if you watch your plant’s health, you will catch the problems in the initial stage.

If your Boston ferns start to lose the color of their fronds, consider the points we just discussed and examine the plant to find out the reasons and take the necessary steps. 

You will notice your Boston fern fronds will become dark green again.


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