Why is my Fern turning brown? Causes and Solutions

Last Updated: June 19, 2022

It’s always concerning when you see that the leaves of your houseplants are starting to turn brown as this is often an indication that something isn’t quite right. It’s important to diagnose the issue early as if there is an issue going on that isn’t solved in time, then this can start to kill your Fern pretty quickly. In this article, we will go through each of the main causes of brown leaves on a Fern as well as give tips on how to treat it and prevent that issue from causing more damage in future.

The most common reasons for ferns turning brown are; a lack of humidity, too much bright light, watering issues and over fertilisation. The first of which by far is the most common problem, and easiest to fix. There is one cause of brown Fern leaves, however, that isn’t always a cause for concern as some browning on the foliage can be normal. This is just a sign that your plant is maturing. Below we will go through exactly how to know and what to look for to suggest that it’s natural or a worrying cause. 

Lack of humidity can cause brown leaves

Ferns love a more humid environment, so if your home tends to have dry air it’s worth your time to try and increase the humidity a little. Dry air will very quickly dry out the leaves on your Fern as they have such thin and delicate leaves. On houseplants with bigger leaves, a lack of humidity will only often cause the tips or edges of the leaves to turn brown. However, because Ferns have such thin and often small leaves too, dry air can impact your Fern quite drastically so it’s important to act quickly when this is happening. 

There are a few really simple techniques to keep the humidity higher than normal for your plant and it’s a good idea to start to get into the habit of carrying out these methods on a regular basis. This will prevent any more of your plant’s leaves from turning brown. 

Firstly, the method we recommend the most is misting your Fern using a spray bottle. You want to be doing this every day when trying to solve the issue, and then every few days once the brown leaves are under control. This will help to give a nice boost to your plant and prevent the leaves and stems from drying out. 

The second method which is a really great one is to use a pebble tray. This requires a little bit more DIY before getting started but your Fern will love you for it. Place your plant over a tray of pebbles that is half full with water. Over the day, the water will evaporate around your plant and prevent the leaves from drying out. It’s super important with this method though that you don’t overfill the container with water. The last thing you want to do is have your Fern sitting in water for long periods of time. 

If you find yourself forgetting to mist your Fern and don’t fancy building a pebble tray, then there are a few methods that require a lot less work. If your bathroom has good natural light levels, then you might want to place your plant in there. The humidity level of bathrooms tends to be a little higher than a lot of other rooms due to the steam released when showering. This means your Fern can thrive in a nice humid environment without you having to add anything extra to your daily routine. 

Another very passive way of making sure that the humidity level is high enough for your Fern is to invest in a humidifier. These affordably little gadgets are great at reaching and maintaining a good humidity level and will do wonders in preventing your Fern from developing any more brown leaves. Our Ferns really love this humidifier which is available on Amazon and is super affordable too! If you want to go a little fancier you can also get humidifiers that work on timers so you don’t even need to remember to turn them on! 

If you’re unsure about whether humidity is a problem for your Fern, or if you are struggling to know when you’ve reached a good humidity level, then you can always pick up a good humidity monitor like this one from Amazon to keep track of everything and make sure the air isn’t too dry. 

A good first move is to relocate your Fern away from air conditioning units or radiators as these create really dry air in your home.

Intense light can also cause brown leaves on your Fern

Lighting is always important to your houseplants and ferns are no different. If anything, due to their super thin and delicate leaves, your Fern is very quickly affected by changes in light. 

If your plant is getting too much bright light you’ll start to notice the tips of the fronds turning brown, this is because Ferns are pretty prone to burning and drying out in intense light. 

Although the brown leaves are now irreversible, preventing any more from developing is pretty simple. All you need to do is find a slightly shadier spot for your plant. You don’t want to make a drastic change and all of a sudden place your Fern in the darkest corner of your home (as that REALLY won’t help things), but you want to move it away from the direct light. Make sure that your plant is still getting plenty of indirect sunlight each day, just stay away from direct sun rays. 

During winter, you can get away with placing your plant a little closer to the window and it won’t matter so much if it receives any direct sunlight. This is because the sun is a lot weaker during winter and out for less of the day. 

If you aren’t sure how much light your Fern is getting in its current spot (or any alternative spots in your home) then we highly recommend using a light meter. They’ll tell you what level of light is in your home throughout the day and you’ll be able to monitor how it varies across the year.

Brown leaves can indicate watering problems

As with a lot of things in the houseplant world, proper watering is an integral part of the puzzle and if you are watering your Fern too much, too frequently, or too little, this can all lead to problems including brown leaves. 

The first thing to do if you suspect any watering issues is to inspect the soil. Carefully remove your Fern from its pot and check to see if the potting mix is waterlogged or super dry. Ferns hate really dry soil but can also start to rot if the potting mix is waterlogged for a long time so finding the right balance is key. Another thing to look at once you have taken your Fern out of its pot is the root system. If the rots have started to crisp up then it suggests you have been underwatering for a while. If, however, the roots have turned quite dark in colour and are soft to touch then this suggests your Fern is suffering from root rot in overly soggy soil. 

If your Fern is too delicate to be removed from its pot then you can also use the finger/chopstick method to see how soggy the soil is. Press a chopstick or one of your fingers around 1″ into the soil. If it comes out clean then the potting mix is very dry. If it comes out covered in the potting mix then you may be overwatering. You can also use a moisture meter to check the soil for a more accurate reading and know for certain when it’s time to water.

How to fix the watering issues and prevent more brown leaves?

If you find the soil is extremely dry, you should soak your plant for about 15 minutes. You don’t want to drown it in water as this can cause shock so giving it a quick soak will let it pick up some of the water. Then water a little once a day for a week to avoid a sudden shift in the environment. 

Most Ferns will come with a good amount of peat moss in the pot and tend to have pretty dense root systems, this makes it very difficult for water to get through when they’ve dried out.

To prevent underwatering from causing more issues such as brown leaves in future, you need to ensure you are watering frequently enough to prevent the soil from drying out for too long. If you always find yourself forgetting to water your Fern then a self-watering pot is the thing for you. It will give your plant the right amount of water without you needing to even be home! We love this one which is available from Amazon. 

However, if overwatering has been the problem and your Fern is sitting in waterlogged soil then you need to fully replace that potting mix. Remove as much of it from the roots as you can without damaging the root system further. Replace with fresh dry mix to allow the plant to start its recovery process and prevent more brown leaves. You also want to trim away any rotten roots. There is no way to save these and trimming them off will encourage your plant to grow new ones. 

We’ve always gone for a little and often view towards watering our Ferns to get nice even moisture in the soil. They don’t like going from one extreme to the other which can be another cause of brown leaves. We’d recommend picking up your Fern when it’s in need of watering and after you’ve watered it, this way you get a feel for when your fern might need a little more simply by giving them a little lift.

There are also a few other things you can do to prevent watering issues and subsequent brown leaves, particularly when it comes to waterlogged soil and drainage. Often, when we buy houseplants they come in plastic pots. These are great for plant shops and nurseries as they are lightweight, cheap and unbreakable. However, they aren’t always the best for our beloved plants as they keep in every drop of moisture. This means if you accidentally overwater without realising or the drainage holes are blocked by something, it can be really easy for the roots to start to rot. 

Instead, if you are using terracotta pots for your Fern, they will allow some of the excess water to evaporate out of the sides of the pot. They can be a real lifesaver when it comes to watering issues so although they cost a bit more to buy, they are definitely an investment worth making.   

Watch out for over-fertilisation

Most generic plant foods and fertilisers will recommend a dosage for your plants, but it’s often far too much for a Fern and can result in browning in the fronds.

Each and every houseplant is different and there are so many factors that determine how much fertiliser your plant will need. Everything from size, location, maturity, and variety as well as environmental issues such as light and temperature levels can affect how much feed your plant needs. This is why it is impossible to have a one-fits-all amount that so many fertiliser bottles suggest.

We often recommend going with less than the recommended amount for most plants but it is especially crucial for Ferns as they have such delicate leaves and stems. Even the slightest overfertilisation can result in browning. 

The best bet here is to try out feeding at half the recommended dosage and see how your Fern reacts. If you notice any browning you can flush the feed out with more water and try again the next time you water with a quarter of the dosage. Our plants have always liked the liquid fertiliser from Miracle-Gro which is available on Amazon here. 

You can also choose to remove fertiliser from your care routine altogether if you don’t want to risk any damage to your Fern. In fact, we recommend this for a few months just to let your plant recover but it’s completely up to you if you choose to go back to it in future. You can have plenty of healthy new growth without any use of fertiliser!

Some brown leaves on your Fern can be normal

Whilst all of the issues above have been problems causing your Fern to develop brown leaves, there is one more factor to consider that isn’t so worrying at all; natural ageing. 

As your Fern matures (and this goes for most other houseplants too), it will prioritise growing new growth over some of its older growth. This is because as it matures it will want to create bigger leaves to add more photosynthesis. 

As this process takes place, some of the older leaves will drop off your plant but will often turn brown before doing so. This is a totally natural process and happens a lot with Ferns. 

But you might be wondering, how do you know if it’s natural ageing or a more serious problem? Well, firstly we recommend ruling out any of the above issues. Check the soil and monitor all environmental factors to see if you can spot something that might not be right. Then the next thing to do is look at your plant to see if it is growing new growth. If your Fern is popping out plenty of new healthy stems and leaves, whilst losing a few of its oldest and lowest leaves, then this suggests natural ageing. As long as your Fern is growing more leaves than it is losing, you shouldn’t need to worry! 

We hope that this guide to diagnosing and treating brown leaves on a Fern has been useful and you have been able to spot what is wrong with your plant. Overall the issues with browning ferns are easy to spot, and not that difficult to start to fix. The key to reviving your Fern though is catching the issues early before they have really taken a hold of your plant. This is why we always recommend giving your plants regular checkups to spot any issues early. 

To find out more about how to care for your plant and prevent any other common problems from occurring, check out our plant index where you can find detailed care guides for more than 100 plants, including many Fern varieties.

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