Problems

Why is my Asparagus Fern turning brown? Causes and How to Fix it

With incredibly delicate leaves, the Asparagus Fern has stolen many plant parents hearts, including ours!

Why is my Asparagus Fern turning brown? Causes and How to Fix it

There’s just something special about them and their ability to bring a little bit of wilderness to our home. However, their beauty does come at a price though as they aren’t the simplest houseplant to care for. They can be quite fussy about their environment and care so it is not unusual for your Asparagus Fern to develop brown leaves (some people call them needles, but we still just call them leaves).

In this post, we will share with you the most common reasons why Asparagus Ferns develop brown leaves, as well as sharing how to fix and prevent the issues to bring your plant back to full health. 

Causes of brown leaves on an Asparagus Fern

In this post, we will be going over each of the causes of brown leaves on Asparagus Ferns and show you how to fix it and prevent the issue from happening again. Some issues are easier to fix than others, some are easier to diagnose than others but don’t worry – we have you covered and will help you get to the bottom of the problem.

 

Lack of Humidity

One of the most common causes of brown leaves on Asparagus Ferns is a lack of humidity (dry air). Because the leaves are so thin and delicate, they are a lot more susceptible to this than the majority of other houseplants. 

Luckily, there are a variety of easy ways to increase the humidity for your Asparagus Ferns, some of which are free, others which take nearly no effort at all: 

 

  • 1

    Misting the leaves

    This is the number one thing you should be doing to keep your Asparagus Ferns happy and healthy. The leaves can dry out super quickly and turn brown as they are so small so misting them regularly is key. Use a spray bottle to mist the leaves at least a few times per week. 

    We recommend only misting your Asparagus Fern in the mornings to give enough time for the moisture to evaporate off the leaves. If your plant is still damp when the temperatures drop at night, then it opens up the risk of the leaves and stems rotting.

  • 2

    Make a pebble tray

    This requires a little DIY but it’s a great solution for Asparagus Ferns that have developed brown leaves due to a lack of humidity. Fill up a tray or bowl with small stones and fill it up halfway with fresh water. Place your Asparagus Fern on top of the stones and the water will evaporate around your plant throughout the day.  

    The most important thing when making a pebble tray is to make sure that the water doesn’t reach high enough so that the roots are sitting in water which will risk root rot. Top up the water when it getting quite low. The frequency will depend a lot on environmental factors such as temperature, sunlight etc.

  • 3

    Placement

    If you have good lighting in your kitchen or bathroom then we recommend moving your Asparagus Fern in there. The humidity level in those rooms is naturally higher because of steam from showering and cooking, making it a great solution for those who might forget to mist, or who don’t have the right things to build a pebble tray. 

    Just be careful not to put your plant too close to the cooker or this will burn the leaves pretty quickly and you’ll have a few more problems than just brown leaves on your Asparagus Fern.

  • 4

    Buy a humidifier

    If you’re worried about the lack of humidity becoming a real problem, then buying a humidifier is probably the best way to go as it’s the most reliable method of increasing the humidity and keeping it at a stable, consistent level.

    They are super affordable devices that also have benefits for us, as well as our plants. They are thought to help to clear our skin as well as improving our quality of sleep. So as well as preventing any more brown leaves developing on your Asparagus Fern, humidifiers are great for our other plants as well as us too! 

    If you want to know more about how to raise the humidity for your Asparagus Fern or any of your other houseplants then check out our detailed humidity guide.

Too much Sunlight 

Asparagus Ferns need bright but indirect light to really thrive. Whilst they can often adjust to less than ideal light levels, growth will be slower and it can also cause brown leaves (see below) as well as other issues for your Asparagus Fern. 

If your Asparagus Fern is sat right next to a window, then it may be experiencing sunburn during summer. Direct light during the hottest months of the year can be very intense and is harmful to the delicate leaves on an Asparagus Fern, often causing them to turn brown and fall off.

If you think that direct sunshine is causing the brown leaves on your Asparagus Fern, try to move your plant a little bit further away from the window so that it doesn’t receive any direct sun. Unfortunately, once your Asparagus Fern leaves have been damaged from the sun, there’s no going back so we recommend trimming off the worst affected stems to encourage new healthy (and green) growth. 

Not enough Sunlight

As well as too much sunlight, not enough can also cause some brown leaves on your Asparagus Fern. Your plant needs a certain level of light to photosynthesise and if your plant is too far from the window then it could be causing the brown leaves. A lack of sunlight is often paired with stunted growth or stems that look as though they are reaching for the light. This issue tends to be more common during winter where the sun is weaker and out for less of the day.

If you think that insufficient light levels are causing the brown leaves on your Asparagus Fern, the best thing to do is start moving your plant a little closer to the window. You want to make sure that you don’t move it somewhere with too much direct light, especially in summer. 

If your home doesn’t receive that much natural sunlight or the winter nights are dragging on for too long, then you can also supplement the light using an LED grow light. These are great for plants struggling with a lack of sunlight as they allow you to control the additional light and will go a long way to preventing any more brown leaves from developing on your Asparagus Fern.

Overwatering 

Another common reason why your Asparagus Fern may have developed brown leaves is too much water.  It can be quite easy to accidentally give your plant too much water and their delicate leaves can be quite sensitive to any damage caused to the root system.

The reason that consistent overwatering can be so harmful to your Asparagus Fern is that it causes waterlogged soil which cuts off air circulation in the potting mix. This can quite quickly rot the root system and prevents your Asparagus Fern from taking in any oxygen and nutrients. It also means that the roots can’t physically support the plant anymore which can also mean the stems droop down as well as brown leaves developing.

Before you take any drastic measures and change your watering routine, you need to be 100% sure that overwatering is the cause of the brown leaves on your Asparagus Fern. The first thing to do is to take your plant out of its pot which will allow you to closely inspect the potting mix and root system. If the potting mix feels soggy and clumpy, then this means your plant has been overwatered. If the roots are soft and mushy it suggests that this issue has been going on for a while and may be harder to revive your Asparagus Fern. 

Ways to fix an overwatered Asparagus Fern:

 

  • 1

    Replace the potting mix immediately.

    It’s crucial that you replace any waterlogged potting mix straight away with fresh, high-quality soil. Don’t wait for the soil to dry out naturally as this will only make the problem worse over the next few days and you risk causing even more damage to an already rotting root system. 

  • 2

    Trim off any soft, mushy or brown roots and leaves.

    You want to make sure that your Asparagus Fern doesn’t waste any vital energy trying to keep dying roots and leaves alive. By removing these from your plant, you allow all energy to be put into growing new healthy green growth. Use clean, sharp scissors to remove any dying parts of your plant.

  • 3

    Adjust your watering schedule.

    Take a look at how often you were watering your Asparagus Fern, and how much water you were giving it each time. Cut back on one of these factors to ensure the problem doesn’t happen again. 

How to prevent overwatering causing any more brown leaves

Now that you’ve addressed the current issue, it’s important that you take measures in the future to prevent overwatering and any more brown leaves from happening again.

 

  • 1

    Only water when the potting mix feels dry.

    There are several easy methods to determine when it is time to water your Asparagus Fern which will help prevent any more brown leaves. The most accurate of which is using a moisture meter. They are affordable little devices that we believe every plant parent should own. Pop the moisture meter into the soil and it will literally tell you how much moisture is in the potting mix. It takes all the guesswork away from watering your plants and will significantly reduce the risk of overwatering. 

  • 2

    Ensure good drainage.

    This will help solve the occasional accidental overwatering as it allows some of the water to escape from the pot. Having several drainage holes in your pot, using a well-draining potting mix that includes perlite as well as switching from plastic posts to terracotta ones are all ways you can increase the drainage for your Asparagus Fern and avoid further brown leaves. 

  • 3

    Downsize your pot if necessary.

    One major factor when it comes to overwatering is the size of the pot and how much soil can fit in it!. If your Asparagus Fern is in a pot that’s much too large for the root system, it means that the soil percentage is higher than it ideally should be and it will take much too long for the potting mix to dry out. This then increases the risk and possibility of root rot which causes several issues, not just brown leaves!

  • 4

    Adjust your watering schedule depending on external factors.

    Although watering calendars can help us remember to water our plants, they aren’t actually the best thing for our green friends as things don’t always work like clockwork. It’s important to adjust how much and how often you water your Asparagus Fern depending on the time of year, temperature fluctuations, sunlight levels and maturity/size of your plant. There’s no one fits all timeline which is why moisture metres are such a great tool for us plant parents. 

Underwatering 

You might be seeing a pattern here, in that brown leaves are often caused by too much or too little of something – and the same is true for water. Asparagus Ferns can be forgiving for the odd time where you forget to water, but consistent underwatering can lead to a variety of issues if not sorted; the most common of which is brown leaves that will quite quickly fall off the plant.

Before you start pouring loads of water over your plant, you need to make sure that this is really the cause of the brown leaves on your Asparagus Fern. As with overwatering, we recommend checking the moisture in the soil, either using the finger method to test how moist the potting mix is or by removing the plant from the pot. If the soil is dry and feels quite sandy to touch, and the roots look a little crispy and shrivelled, then underwatering is likely the cause.

How to fix an underwatered Asparagus Fern:

 

  • 1

    Give your plant a soak.

    Fill up a container with fresh temperate water and place your plant in there for about 10 minutes. Avoid hot or super cold water as this can shock and burn your plant (they are even more sensitive to this when other issues are occurring). This method allows the water to soak into the potting mix and your plant will only take up as much as it needs. Often when watering really dry soil, it flows right through and out the bottom of the pot which doesn’t help solve the issue.

  • 2

    Slowly reintroduce watering.

    Sudden changes in the environment can be quite stressful for plants and if the potting mix goes from really dry to super soggy quickly, it can cause your plant to go into shock (this is why we recommend only soaking for 10 minutes). For the next week or so, slowly reintroduce watering by giving your plant a little every day before returning to a more normal schedule. 

  • 3

    Adjust your watering schedule.

    If you had simply forgotten to water your Asparagus Fern and that’s why the brown leaves appeared, the fix is easy – just make sure to remember, make a note of it or ask a friend to help you out. However, if your watering routine just wasn’t enough for your Asparagus Fern then going forward make sure you are keeping an eye on when the potting mix is dry so you know when it’s time to water your Asparagus Fern. Using a moisture meter is a great way to avoid any more brown leaves caused by a lack of water in future.   

Temperature Extremes 

If you have inspected the potting mix of your Asparagus Fern, checked the light levels and regularly boost the humidity and can’t be sure that the above causes are the right fit for your Asparagus Fern, then it may be extreme temperature fluctuations that are the problem. 

Asparagus Ferns are native to South African so thrive in warm temperatures meaning they’ll struggle in homes with cold drafts. You may not notice the cold air coming through cracks in doors and windows but if your Asparagus Fern is right next to any cold air streams then this can over time be a real issue. 

Make sure that you draft proof any windows/ doors that are close to your Asparagus Fern (and other tropical or heat-loving houseplants) as well as moving them away from any air conditioning vents as these can be quite damaging to your plants during summer. Using a digital thermometer is an easy way to monitor the temperature in your home and allow you to check for any cold drafts.

If your Asparagus Fern is in quite a cool room, this can also increase the risk of overwatering and root rot (which brings us back to the overwatering problem) Your Asparagus Fern won’t need as much water as the soil will take a lot longer to dry out in cooler temperatures. This can be the perfect place for root rot and leaf rot to occur so be extra cautious when it comes to caring for your Asparagus Fern in winter or in colder rooms in your home. 

Warm temperatures and hotspots next to windows that can be formed from direct sunlight can also dry out your Asparagus Fern and cause brown leaves. Using a temperature monitor can also help you avoid this problem, as well as moving them at least 1 metre away from radiators, stoves and heating vents.

Natural ageing 

There’s one more cause of brown leaves on Asparagus Ferns which is actually not a problem at all – natural ageing. As your plant matures, it will want to spend most of its energy on the new growth. This can mean your plant drops some of its oldest, often lowest leaves. If you find that a few stems and leaves are turning brown at quite a slow rate then this could be the reason. 

This is absolutely nothing to worry about as long as the rate of browning is slow, then it’s just simply part of the natural ageing cycle of your plant. You can trim away the brown leaves or leave them to fall naturally.

Should I trim away the brown leaves off my Asparagus Fern?

We get this question a lot, and we do recommend trimming away any stems that have gone brown. If the occasional leaf (needle) on your Asparagus Fern is brown, then leave this alone. However, if a large chunk of a stem is brown then remove this part. Once the stems are brown, there’s no bringing them back to green, unfortunately, so removing them will allow your plant to focus energy on new healthy growth. Always use clean scissors when removing stems so as not to pass any pests or bad bacteria onto your Asparagus Fern. Make sharp cuts instead of just tugging at the stems to make sure you don’t damage your plant.

So those are the most common reasons why your Asparagus Fern has developed brown leaves. It is quite a long list of reasons, so we recommend going through each one and discounting them if they don’t apply to your plant. Get up close to your plant, inspect the potting mix as well as the environment and your care routine and you should be able to diagnose the problem pretty quickly. 

If you have caught the issue early, there’s no reason why you can’t bring your plant back to full health by changing up the environment or your care routine. Keep an eye on your plant after making any changes to make sure the issue isn’t getting any worse. 

To find out more about Asparagus Fern care, as well as other common issues and propagation advice, check out our Asparagus Fern care guide.

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