Monsteras are quite a common plant for people to have in their homes and as such, there are some common traits that people have noticed over the years.
We’d like to preface this article by saying – don’t worry too much initially. There are numerous reasons why your monstera might have black spots and some of them can be easily resolved.
Some reasons however can be more serious. Luckily, we’ve compiled this guide to help you clear some of these reasons up and hopefully get your plant back to fitness.
Read on to learn more.
What Is A Monstera?
Before we go any further, it’s best that we explain what a monstera is for those who may be unfamiliar with them.
Monsteras, often known as the Swiss Cheese Plant are large beautiful plants with green leaves. These leaves are also large with holes or gaps and appear with a dark green color.
They tend to be tough plants and are usually very low maintenance. As they come from Tropical climates, they enjoy indirect sunlight and moist soil.
Why Might My Monstera Have Black Spots?
As we previously mentioned, there are a variety of reasons why your monstera plant may have black spots.
In fact, sometimes the spots are not exactly black but can be brown – and other conditions can make the spots yellow.
If you have noticed black spots on your plant though, it could be due to these following reasons:
Root rot through overwatering
Sunburn
Underwatering (dehydration)
Damage to the plant
Cold weather or cold conditions
Low humidity
Not receiving enough indirect sunlight
Misting
Disease
Pests have got to it
Some of these are more likely to be the case than others, so we’ll look at them in order of likelihood below.
Root Rot
We love to take care of our plants, but sometimes we can go a little overboard. We water them far too much. Resultedly, it is very common for plants to develop root rot.
While some plants and indeed flowers, need lots of water – others do not. The monstera is one such plant that does not require as much water as you think.
Root rot may also be shown if the leaves have started to yellow a little bit. There is a little bit of good news though, when a monstera is showing signs of root rot, it can be treated.
It’s important to note though that if the plant’s leaves have changed color, it’s unlikely they will return back to their usual dark green color.
To resolve this issue, you can take the plant out of its pot (carefully of course) and wash the roots of the soil. Cut off any leaves or roots that look like they’ve had their day.
Next, place it into a jar of clean, room temperature water. It’s important that the leaves are only in water though and every few days or so, change the water and eventually you will notice brand new roots growing.
This process is the best way to do it because root rot is caused by the roots being attacked by bacteria and turns the roots mushy, accompanied by a foul smell.
Whilst it may seem counterintuitive to place an overwatered plant back into water, there is a perfect reason for this.
As plants growing in water will grow water roots (vice versa for soil), they will be able to extract oxygen.
In other words, they are developing the way they operate that suits their situation to ensure their survival.
Underwatering (Dehydration)
Conversely to the previous point, your monstera might be struggling and develop black spots because of a lack of water.
These plants enjoy water, but this is only when they are very dry. The best way to know for sure is to look out for a moisture meter in a garden store.
You may also benefit from asking a professional exactly how often you should be watering your plant, because oftentimes once a week is much too frequent.
Even if you water your plant correctly, you may notice that it is almost automatically disappearing or the water is not being absorbed correctly.
One of the best ways you can try to ensure your plant is getting enough water is to bottom-water it.
In other words, instead of providing the plant with water from the top of the soil to reach the bottom, go the other way around and water it from the bottom of the soil to the top.
Leaving the bottom to soak for a few minutes is a good idea here. If the plant is particularly large, consider using a bath or similar.
This is a great way to resolve monstera’s that have developed hydrophobia (a fear or resistance to water absorption).
During hydrophobia, your plant will flow the water in the gap between the top of itself to the soil and through cracks.
If the soil is still not absorbing water correctly, it may be rootbound. You can easily check this by examining the roots for an encircling rootball.
This needs a simple solution. All you’ll need to do is re-pot the plant, but make sure you don’t put it into a much larger pot because you’ll be at risk of overwatering the plant and then having the previous problem on our list!
Simply buy a slightly larger pot and continue as normal.
Sunburn
Now, we hear you say – can plants get sunburn? Well, yes they can!
Remember, these plants are initially from tropical areas where they do not receive lots of direct sunlight. Instead, they receive indirect sunlight covered by other large and imposing trees.
The best thing you can do is to place your plant near windows with plenty of indirect sunlight.
Other than that though, you could try to gradually acclimatize your plant to the sun by giving it small amounts of direct sunlight.
Of course though, this will take a very long time – but people have done it previously to a point where their plant can live outdoors during the summer months!
Damage
Swiss Cheese Plants that have had physical damage can show black markings. Most plants do not like being touched and this is no exception, especially when it comes to new growth.
Many people may be tempted to touch their plants and inspect the leaves on both sides, but it’s best to try to resist this urge to do so.
If you have caused damage and then notice black markings or brown markings, they may reverse over time.
It’s important to note too that if you live with animals, try to keep them away from the plant!
Cold Conditions
It probably goes without saying that tropical plants aren’t designed for the cold weather.
One of the most common reasons why these plants get black spots is because of cold conditions, especially sunrooms that are unheated.
This is all very well in the summer months, but when it goes to fall and winter, the plant will seriously start to struggle.
The black markings may be primarily caused by the plant trying to conserve its energy because it is not getting any from the sunlight, but also due to lack of humidity and low temperatures.
It could also be due to the plant’s lack of immunity, and as a result it attracts diseases or pests. Whatever the reason, the cause is usually cold conditions in this example.
The best way to curtail this problem is by either heating the room up or moving the plant to a warmer room.
Low Humidity
This is sort of an add on to the previous point. Now, it’s important to note that these types of plants aren’t massively that caring about humidity, although they will thrive with higher humidity levels.
All this means is that if you’re living in a dry environment, the leaves of your plant may end up looking brown, black or even crispy.
There is luckily something you can do if you live in this type of environment though, and that is you can purchase yourself a humidifier. You want the level of humidity for your plant to be around the 40% level.
Misting
This point feeds into the overwatering point on our list. The fact is, these plants hate getting their leaves wet.
Eventually, if you do this by misting, you’ll cause either root rot or some type of bacterial disease.
Some people claim that misting is useful because these plants come from tropical areas where rain is common, therefore the leaves get wet every now and then.
However, it’s advised that you don’t bother misting if you want to avoid black or brown spots on the leaves.
Lack Of Sunlight
Whilst it is important to give your monstera plenty of indirect sunlight, once again – they come from conditions where it is common to not receive much light due to imposing, large trees.
As a result, they have evolved to not need as much light as people may think.
However, to ensure that the black spots are not caused by a lack of indirect sunlight, it’s best that you place your plant near windows with enough coming through.
South-facing windows are the best areas for these types of plants.
Disease
There are numerous diseases that can befall your plant, so it is difficult to say exactly what diseases might be the cause of your plant’s black spots.
If you want to be sure, you’d be advised to contact a professional who might be able to look into this for you.
Pests
Pests are not usually the cause of brown or black spots on your plant, but they can make the problems much worse and eventually, the spots begin to grow or darken and even spread.
This is often because pests can be attracted to diseased or compromised plants, so be sure you keep an eye on your plant’s progress over time.
Once again, it’s a good idea to speak with an expert about the pests that could be a problem and how you might get rid of them.
Avoid the urge to use a chemical or simply slice off the affected area as this might make the problem much worse to deal with.
Frequently Asked Questions
Here are some additional frequently asked questions about caring for monstera plants.
Should I Remove Leaves With Black Spots?
There’s no right or wrong answer to this. The only time you should certainly remove a black or brown spotted leaf is if it is diseased.
If it isn’t, the plant will not be in any harm from the discoloration, although the green color may not return.
Whilst you can trim the affected area, it is advisable to leave the plant as it is because you may inadvertently cause problems for the plant’s ability to photosynthesise.
Do I Need To Use Fertilizer?
It’s logical to think that due to the speed in which this type of plant grows and develops, that it would need lots of plant fertilizer, right?
Well no. Much like water, monsteras do not need lots of fertilizer, and in fact – many would argue against using it to begin with.
During the winter months though, it may be a good idea to use fertilizer once at the start of each of these difficult months.
Are Monsteras Toxic?
Tropical plants tend to be toxic, and this one certainly is. If you have pets – especially cats – try to find a way to keep them away from this plant at all times.
This is because they may have the urge from curiosity to nibble on the plant’s leaves. Whilst this is, of course, a problem to your plant – it will also lead your furry friends straight to the vets!
On the same note, small children should be kept away from these plants too, and if you’re going to handle your plant – ensure you’re wearing gloves and always wash your hands thoroughly afterwards!
The Leaves Are Dropping – Do I Need To Worry?
Absolutely not. Generally, these plants will drop their leaves so new stems and leaves with nutrients can thrive better.
However, there are some other reasons for these leaves to drop which aren’t due to this. Typically though, you will notice other unusual things happening like discoloration or a foul smell.
How Often Do I Need To Repot My Plant?
We mentioned repotting might be a solution to underwatering earlier in this guide. What you have to remember is that these plants grow very quickly.
However, some people have the urge to repot their plant much too early and risk overwatering it.
Whilst it is impossible to tell you specific dates for when to repot your plant, we can say as a general rule of thumb that repotting every two years is advisable.
Can I “Shock” My Monstera?
It’s highly recommended that you do not do this. Shocking techniques have been shown to cause death with these plants.
While some people may have said that it has worked for them, the vast majority of times it will make things much worse.
Hi, my name is Amy Enrich and I have had a keen green thumb since my parents first taught me how to sow a sunflower seed. The process of watching it grow from seed to sprout, sprout to shoot, and then to a full-blown plant is a wonderful sight - I never get bored of it!
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