Fern Leaves Turning Brown

Fern Leaves Turning Brown

Ferns are an interesting group of plants, comprising more than 10,000 different species, that do not reproduce via seed as other plants do. Instead of sexual reproduction through pollination, ferns have spores that are found on the undersides of their leaves, or fronds.

The size of ferns can range from small plants that grow well indoors, to those that are almost as tall as a tree. But, although they may vary in shape and size, their preferred living conditions are generally quite similar.

One of the most common problems encountered by fern owners is when the leaves of their plants start to turn brown. The most common causes of this discoloration are too much light, watering issues, humidity problems, excessive fertilizer application, and pot size.

In this article, we will discuss each of these causes and how you can resolve them. So, if you are currently facing this problem with your own fern and wish to learn more, just keep reading.

Why are my fern’s leaves turning brown?

Too much light

In their natural habitat, ferns grow under a forest canopy where they receive filtered light or complete shade.

They are not adapted to tolerate full sun exposure, so if your fern is exposed to too much sunlight, its leaves – or fronds – will lose moisture at a faster rate than its roots can absorb it, causing the leaves to dehydrate and turn brown and crispy.

Excessive sunlight may also reduce the humidity around your fern, as well as raising the temperature to an unfavorably high degree, both of which can contribute to the fronds turning brown and dying back.

Always keep your fern in an area that gets filtered light or shade to ensure that it remains healthy.

Remove any brown, sun-damaged fronds to help stimulate new, healthy, green growth on your plant.

Watering issues

If you notice that your fern is turning brown, one of the first things you should check is whether you are watering it too much or not enough.

Ferns like their soil to be moist but not soggy most of the time. Having completely dry soil can be stressful, so try not to let it reach this stage.

Because of their bushy shape, some types of ferns can be quite difficult to water. Try to get as close to the center of the plant as you can, so that you give it a thorough watering every time. A watering can with a long spout is very helpful – even for a very bushy fern, you should be able to direct the water exactly where you want it to go, thanks to the long spout.

Because ferns are so finicky when it comes to watering, people frequently make mistakes with them. In an attempt not to let the soil dry out, it is easy to overwater the plant instead. If you think your fern may be turning brown due to overwatering, reduce your watering frequency and keep an eye on the results to know whether this was the problem.

Humidity problems

Low humidity can cause ferns to turn brown and dry out quickly. These plants need high humidity levels to thrive, and lower levels will affect their lush, green fronds.

If you live in an arid climate, that does not mean you cannot grow ferns; there are a variety of artificial methods to increase the humidity in the room where you keep your plant.

Purchasing a small humidifier is the easiest solution. To ensure that your ferns get the humidity it needs, simply place a humidifier in the same room.

If you do not have access to a humidifier, try misting your fern on a regular basis. However, depending on how low the humidity level is in your home, this may not be sufficient to keep the fern healthy and green.

You can try placing it in areas of your home where the humidity levels are higher, such as the bathroom or the kitchen. You can also place its pot on a tray filled with water and pebbles; as the water evaporates from the tray, it will moisten the air around the plant.

Excessive fertilizer application

The use of fertilizer on ferns is permissible and, when done correctly, can support the plant’s strength and health. However, it is possible to overdo things and use more fertilizer than necessary, especially if you are a beginner.

If you give your fern too much fertilizer, the roots may become burned and the leaves will turn brown and dry out. It is therefore important to exercise caution when fertilizing your plants. 

Many houseplant fertilizers come with dosage instructions that are either too much or too strong for ferns, so it is safer to reduce the recommended strength by half. This should allow you to see some benefits without having to be concerned about the consequences of over-fertilizing.

Fertilize your fern once a month during the spring and summer, but stop completely during the fall and winter.

Pot size

Fern leaves will turn brown if the plant’s pot is too small and the roots are crowded inside it. If a fern is kept in a too-small pot for a long time, its roots will also deplete the potting soil of nutrients, and the root system will become so extensive that it consumes more water than the soil can hold.

Furthermore, small pots dry out much faster than large pots, because they contain less soil and have a lower capacity to hold moisture. The combination of less soil and more roots will result in dehydration, which is why the foliage turns brown and withers.

Your fern will do best in a pot that is as wide as it is deep; this is most suitable for a fern’s shallow but wide root system.

The best material for the pot is glazed clay, because this is a porous material that allows the soil to dry out more evenly. In contrast to impermeable plastic pots, which leave plants more susceptible to root rot and other problems, a porous pot is far less likely to cause these problems.

The pot also has to have drainage holes at the base to allow excess water to drain after watering.

High temperatures

If the temperature rises above 80 degrees Fahrenheit, your indoor fern will start to turn brown.

Ferns prefer temperatures in the 65 to 75 degrees Fahrenheit range, but they are able to tolerate temperatures beyond that range better than some other plants. Under hotter conditions, they will start to lose more moisture from their leaves than they can store in their roots.

In the cold winter months, when indoor heating is on and temperatures can rise significantly in the evenings, the high temperatures can become a problem and the temperature fluctuations can stress your fern.

To keep it happy, place your indoor fern in a room where the temperature is 65 to 75 degrees Fahrenheit. The bathroom is usually the best place because it has naturally higher humidity and generally cooler temperatures than the rest of the house.

Remove any brown foliage, because it will not recover. Pruning the brown leaves encourages the growth of new, healthy, green leaves.


Ferns are some of the most interesting plants you can keep in your home. Unlike other plants, they reproduce by spreading their spores in their surroundings.

These plants are quite low maintenance and easy to grow, but that does not mean they do not have their fair share of problems. One of the most common problems reported by fern owners is when the leaves of their plants turn brown.

The probable causes of browning fern leaves are too much light, watering issues, humidity problems, excessive fertilization, and incorrect pot size. The sooner you can identify the precise cause of your plant’s discolored foliage, the sooner you can take action and return it to full health.

Image: istockphoto.com / Ewa Saks