Monstera Leaves Turning Black

Are those black spots on your Monstera leaves bothering you? You may even fear that your plant will die soon. The good news is that Monstera deliciosa is an extremely resistant houseplant that you can possibly recover from problems like its leaves turning black. Trust me on this, all you need to do is give it the right amount of care.

In this article, I will address some of the key causes of why monstera leaves turn black and what you can do to heal your favourite houseplant. So, why exactly are your monstera leaves turning black?

black patches

Table of Contents

Why Do Monstera Leaves Turn Black?

There are many reasons your monstera leaves might be turning black, such as improper watering, pests, temperature and humidity problems, sunburn and misting, or diseases. Learn more about the causes of black leaves on monsteras and what you can do to solve the problem:

plant's leaves Monstera

Overwatering

Many beginners overwater their plants out of the misguided belief that more water equals more love. In reality, too much water can cause root rot–which manifests as black spots on leaves. Generally, overwatering is quite hard to spot.

You’ll get to know about it only when it gets out of hand, but you can recover from the problem if you provide immediate attention and care. The early sign of overwatering is the leaves turning yellow or the stems becoming soft.

Underwatering

Just like overwatering, underwatering can be a reason why your monstera leaves are turning black. If you notice the leaves turning light brown, be sure to water the plant. Moreover, touch the soil and see if it feels dry. If you think the soil is too dry, it’s a clear sign of underwatering and it is best that you water the plant right away and more frequently.

healthy plants Monstera

Sunburn

If you are keeping your monstera plant in indirect sunlight, under a lamp, or in front of a window, you’re exposing the plant to a lot of heat energy. Excessive heat leads to dark, crispy, and toasty patches on your monstera leaves and stems. These patches appear oval or round in shape.

Misting

Misting has lately grown in popularity among more and more gardeners, I believe as a result of social media and movies. Perhaps it looks attractive to stand around the house with a spray bottle in hand, admiring the droplets on your plants’ leaves. I’ve seen unskilled gardeners do this too often, but I don’t recommend it.

I mean, misting frequently is not good for plants. Misting actually increases the humidity levels. Understand that the spray bottle’s content is not mist, but water. This will cause water to amass on leaves’ surfaces, which then attracts insects and can cause fungi. If left untreated, this will lead to darkened spots appearing on the leaves.

Depending on the humidity levels at your home, that is, how dry the air inside your house is, the frequency of misting your plant may range from every day to once a week.   

fungal diseases caused by misting

Lack of humidity

If the air around your plant isn’t sufficiently humid, the leaves could turn black in a few areas. While it may be confusing at first, when you realize that the air inside your home is really dry, misting becomes your go-to strategy. As a general rule of thumb, know the humidity levels of where you live and how often you should mist accordingly as monstera plants can be affected by both high and low humidity environments.

Over-fertilizing your monstera

Of course, your favourite houseplant needs extra nutrients for optimal growth. However, over-fertilizing can make your leaves turn black. If you feel you’ve over-fertilized your plants, don’t worry. If you’ve used a removable fertilizer such as a pellet or a fertilizer stick or a slow waterer with fertilizer, you can just remove it and make sure you’ve watered your plant sufficiently.

Just in case you’ve used a liquid fertilizer, rest assured that it wouldn’t kill your plant immediately. However, you’ll learn that your plant doesn’t require as much fertilizer the next time.

fertilizing monstera plants

Root rot

Root rot is usually caused by several things: waterlogging, heavy soil that doesn’t drain properly, or the plant being potted in a container with no drainage. You can spot root rot initially by the yellowing of the leaves and the softening of the stems. The yellow leaves eventually turn black if left untreated.

The possible solution to root rot is to carefully remove the plant from the soil, cut off the rotten parts of the roots, and repot the plant in a new pot containing a new soil mixture.

Anthracnose

Anthracnose is a deadly disease caused by Colletotrichum, a type of fungus. It usually leaves oval spots (caused by dead tissue) on the leaf, primarily near the main vein. The anthracnose initially appears as brown and yellow spots. If there is a severe infestation, the leaf darkens, may curl up, and eventually fall off. It probably means the fungus has destroyed the entire leaf tissue and is taking all the water and nutrients for itself.

The plant’s immune system is another reason for the dark spots on the leaves. The immune system acts by preventing the flow of water and nutrients to the infected part of the leaves in order to stop anthracnose from spreading to the other parts of the plant.

brown spots

Pests

While monstera is highly resistant to pests, it sometimes can’t defend itself against a few leaf-snacking insects. The most common pests attacking the monstera are spider mites and thrips. These pests are known to bite the leaves of your plant and leave tiny, nasty-looking, black dots on them.

Initially, you may think that it’s not a big problem, but they’ll soon spread all over the plant and attack the other evergreen houseplants as well.

How to prevent monstera leaves from turning black?

I have some useful tips for you on how to take good care of your monstera and prevent its leaves from turning black.

The right amount of watering

The monstera plant thrives well in evenly moist soil. It doesn’t tolerate dryness well. I suggest you water your plant when you find the top inch of the soil to be dry. This could be done once every two days or four days, depending on the temperature and humidity inside your home. Also, don’t forget that you need to water the plant when it needs it, not based on a strict schedule.

Use of fertilizer

Fertilize your monstera every two weeks or once a month. If you see signs of over-fertilizing, you can adjust the fertilizing schedule accordingly. Avoid misting your plant with fertilizer as it can lead to bacterial growth.

Soil

Make sure the soil you’ve used for your monstera drains well. Use a planter with drainage holes to avoid waterlogging. If you’re suspicious of root rot, remove the plant carefully from the soil, cut off the affected part of the root, and place the plant in a new planter containing a fresh soil mixture.

Temperature and humidity

Monstera plants thrive in environments that are similar to tropical climates. So, make sure the temperature inside your home is between 18 and 29 degrees Celsius. You can maintain a decent humidity level around your plant by misting your plant in the case of low humidity or using a humidifier when the humidity levels are higher. 

Position of the plant

Place your monstera in an area where the plant is not exposed to too much direct sunlight. Of course, a little bit of sunlight will not kill your plant, but indirect sunlight is ideal for this plant.

Precautions against diseases

If you notice black spots developing on any of the leaves, it is best to get rid of them because they could be a sign of a disease. Keeping the leaves dry is a great way to prevent your monstera from developing fungal and bacterial diseases. If you find an infected leaf, cut it off using a pair of scissors immediately.

Tackling pest infestation

At the first sight of pests on your plant, remove it from that location and place it separately so that the pests don’t affect the other plants too. If you see visible signs of damage caused by pests on your leaves like tiny dots and holes, remove those leaves immediately. Remember to sanitise any tool you use on your pest-infested plant. I would recommend spraying neem oil on your monstera plant or wiping it down with rubbing alcohol to get rid of the pests in a natural way without causing any harm to the plant.

thrips damage monstera

Conclusion

As you can see, there are several causes for your monstera leaves turning black. I believe you’re now familiar with them. Perhaps, the more you know about these causes, the easier it becomes to care for the plant when it gets sick. Let me walk you through the important points you need to remember:

  • Overwatering and underwatering can make monstera leaves turn black, so water appropriately
  • Maintain the ideal temperature and humidity levels
  • Check the plant often for infection by pests or diseases
  • Overuse of fertilizer can be detrimental to a plant
  • Don’t place the plant in areas where it is exposed to direct sunlight
healthy monstera

People Also Ask

Should I remove the monstera leaves that have black spots?

Well, it depends on the cause. If the black spots are a result of environmental factors such as temperature or humidity, or improper watering, you don’t have to actually remove the leaves until and unless they are damaged severely. On the other hand, if the black spots are caused by pests and diseases, you should remove the affected leaves to prevent the spots from spreading.

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Oliver Wright
Oliver Wright

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