Why is my Boston Fern losing leaves?

The most popular and famous of the Fern family, the Boston Fern is a great way to bring some of the tropics to your home. However, if your Boston Fern has started losing some leaves, then this could be a sign that your plant is unhappy with either the care it’s receiving or the environment in which it’s growing. In this post, we will go through each of the individual factors for leaf drop in Boston Ferns, guiding you through how to diagnose the issue, treat it and then prevent it from causing any more leaves to drop from your Fern.

Don’t mistake it for natural shedding

Boston Ferns naturally lose a lot of their leaves. This isn’t always because something is wrong but is just a characteristic of their delicate and thin leaves. This means that even if your Boston Fern is losing quite a few leaves, it can still be absolutely nothing to worry about.

The main thing here is ensuring that the leaves that are falling off are the oldest and smallest leaves and that the new leaves and stems are healthy. Another factor that will help you establish whether or not your Boston Fern is losing leaves due to natural shedding is whether your Boston Fern is growing more new fronds and leaves than it is losing.

If you are still concerned about the number of leaves your Boston Fern is losing and you find yourself constantly sweeping up after your Fern, this might signal something more serious, in which case read on…

Underwatering can also cause your Boston Fern to start losing leaves

One of the more common factors when it comes to Boston Fern plants losing their leaves is consistent underwatering. Boston Ferns need a lot of moisture to properly thrive and hate it when their soil gets too dry. They have very delicate stems and leaves so you need to keep the moisture levels up. If their roots become crispy due to underwatering, this will lead your Fern to lose leaves to conserve energy.

Before you start changing anything about your watering routine, whether it’s how frequently you water, or how much you give it each time, it’s important to confirm that underwatering is causing your plant to be losing leaves often.

To confirm whether underwatering is causing your Boston Fern to lose leaves, take your Fern out of the pot to inspect how the potting mix feels. If underwatered, the potting mix will fall apart and feel very sandy to touch. You will also see that some of the roots have started to crisp up if you have been underwatering your Boston Fern for a while. This level of dryness is a no-no for Boston Ferns and is almost definitely the reason why your plant is losing so many leaves.

To solve the problem and stop the leaf drop from progressing any further, slowly reintroduce water to your plant rather than drowning it (they can go into shock if there is a sudden change in the environment). A little bit of water once a day for a week should get your Boston Fern back on track and prevent it from losing any more leaves.

Moving forward, to prevent your Boston Fern from losing any more leaves in future, make sure to prevent the potting mix from drying out for extended periods of time. Using a moisture meter can really help with this and you’ll be able to get into a regular watering routine. Just be sure to adjust your routine throughout the year, as temperature and light levels can have a real impact on how quickly the soil dries out.

A lack of humidity could also be to blame for your Boston Fern losing leaves

Alongside frequent watering, Boston Ferns need a high level of humidity to be happy and not crisp up. Unfortunately, their ideal level of humidity tends to be a little higher than the average home which means you will have to give the humidity a boost to stop it from losing leaves. This will become a bigger problem over winter when we have the heating on throughout the day which dries out the air. If the leaves on your Boston Fern have gone dry, crispy and brown in colour before falling off your plant then this may be the cause.

There are two methods we recommend to boost the humidity for your Boston Fern and stop your plant from losing so many leaves. Firstly, misting your Fern daily, even twice a day if the air is super dry. But if you don’t have time to do this then you should really invest in a humidifier to keep a nice stable humidity level. These will really help stop your Boston Fern from losing too many leaves.

When it comes to misting your Boston Fern, avoid doing this in the evening as if the leaves are still moist when the temperature drops overnight, it can cause the leaves to rot. This can happen to most houseplants but because Boston Ferns have such thin delicate leaves, it’s even more of a concern. Misting in the mid-morning is best as it allows enough time for the water droplets to evaporate off your plant. You also want to make sure you are using temperate water, as any extremely hot or cold water can shock or burn the leaves on your Boston Fern, causing further issues.

You can also make a pebble tray for your Boston Fern. All you need for this is a tray or deep plate and a good few handfuls of stones. Fill the bowl up with water but just make sure that the water level doesn’t reach the plant as this will mean the roots are constantly sitting in a puddle of water. Instead, you want the water to evaporate around your Boston Fern, preventing the leaves from drying out and crisping up and eventually falling off.

You might also want to move your Boston Fern to the bathroom if you have great natural lighting in there. Because of showering, bathrooms often have a little higher humidity than the rest of the room which makes the perfect environment for your Boston Fern without having to do anything extra.

Chemical sensitivity might also be why your Boston Fern is losing leaves

Most generic plant foods and fertilisers will recommend a dosage for your plants. However, there are so many factors that play into how much fertiliser your plant needs. From size, age, light levels, temperature etc. Because of this, it’s impossible for there to be one standard amount for every plant.

Boston Ferns can be quite sensitive to fertiliser so the recommended amount is almost always too much and can result in your Fern losing leaves. This is because they have such delicate leaves which can be a bit oversensitive at times.

The best thing to do here is to try out feeding at half the recommended dosage and see how your Boston Fern reacts. Try also decreasing the number of times you fertilise your Boston Fern each year. A few times during the growth period of spring/summer will definitely be enough.

Those are the four most common reasons why your Boston Fern has started losing its leaves. It’s definitely one of the more common problems that plant parents face when it comes to Ferns and there does always tend to be a degree of natural shedding no matter if the care and environment are what your Boston Fern needs.

However, it’s important to recognise the difference between your plant losing a few leaves, and there being a real issue. Keeping a close eye on your plant, and checking in with it every time you water is a great way to monitor any changes and allows you to catch any problems early, before they have really taken hold of your Fern, giving you the best chance at bringing your plant back to full health.

Learn more about how to look after your plant in our Boston Fern care guide.