In an ideal world, our houseplants would be all green, all the time. But when you wake up one day to, say, your Monstera having grown black spots seemingly overnight, you wouldn’t be blamed for being concerned.
Fortunately, learning how to fix black spots on your Monstera really isn’t that hard. As you’ll see, through the process of elimination, you’ll find it to be fairly straightforward to get your plant back to its happy, thriving self.
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Why does my Monstera have black spots?
Your Monstera may have black spots because of overwatering, underwatering, excess direct sunlight, low humidity, pests, improper fertilization, fungal or bacterial infections. However, Monstera is a low-maintenance plant and thrives in different environments. This means it likely only means it needs a bit of attention from you and it’ll be back to its healthy self in no time.
Of course, even if it’s one of the easier houseplants to look after, it’s important to still give your Monstera the care it needs. For that reason, keep reading to see just why your plant may not be quite looking its best right now.
Knowing how often to water your Monstera can be challenging, but it’s important to take the time to work this out given that too much water can cause major problems with your houseplant. In the case of an overwatered Monstera that’s getting more water than it needs, its roots may start to rot, attract pests and get bacterial infections.
Other signs of overwatering can include your Monstera’s leaves turning yellow or brown, soil that takes too long to dry, a strong smell from the soil or even visible mold, so keep an eye out for any of these alongside your Monstera’s black spots.
2. Excess sunlight
There’s a saying that “you can’t have too much of a good thing” and the same applies to Monstera plants. While sunlight is crucial for new Monstera growth, too much light can damage it and lead to your Monstera developing black spots.
Your Monstera can get sun damage if it gets too much light, whether that light is too intense or goes on for too long throughout the day. This can result in sunburnt Monstera leaves, which is how marks start to form on them.
You can find out more about Monstera’s light requirements in our article on this topic. In brief, though, while Monstera does well in low light, it grows faster and healthier when it’s placed in bright, indirect sunlight.
If you notice dark spots on your Monstera and think that excess light could be the problem, be sure to move it from the direct sunlight and consider adding a sheer curtain to filter the light.
3. Low humidity
Low humidity in your home can cause Monstera plants to have black spots. As a plant that’s native to central America, your Monstera needs a certain level of humidity in order to thrive.
The reason for improper humidity levels being a problem for plants is because they have small openings known as “stomates” that close when there’s warm weather to allow the plant to hold on to its water.
Stomata are in charge of how gases like carbon dioxide and oxygen flow in the plant. For example, when the stomates close due to low moisture in the air, the plant cannot get enough carbon dioxide for photosynthesis. In extreme, long term cases, a plant can also die from this.
Another sign of this is If your Monstera is drooping. If you notice that along with some crispier than normal leaves, which may also lead to them shriveling a bit, it may be time to check the humidity levels around your plant.
Find out more: 12 Proven Tips to Get Your Monstera the Humidity It Needs
4. Pest infestation
Pest infestations can, unfortunately, leave your otherwise green Monstera with black spots or even yellow spots.
Some of the prime suspects here include aphids, spider mites, scale, whiteflies, root mites or thrips on your Monstera, depending on where you live. Unfortunately, the signs for this can be pretty similar to some of the other potential problems on this list. However, you can often see evidence of the relevant pests when you closely examine your plant.
That is, even if you can’t see the bugs themselves, you may see webbing or other “souvenirs” that the pests may have left behind. If any of these appear, it may be time to pull out the pesticide spray.
5. Fungal infections
Fungal infections can cause dark spots to form on the surface of your houseplant’s leaves, which can later turn into black spots on your Monstera. If not treated, the black spots can spread, making the other leaves change to yellow with black spots.
This means that this is one particular problem that needs to be addressed quickly. Otherwise, if you leave it for too long, it can spread throughout your plant and kill it.
The exact cause of this can vary, though. For example, wind and water can spread fungi. Alternatively, if you have been working on another infected plant, you can accidentally transfer the infection to your Monstera if you didn’t take the proper precautions. In addition, contaminated soil, seedlings, tools, and people can cause fungal infections in your Monstera.
In fact, one of the main things that causes fungal infections in houseplants is when people bring home new plants. They’re so excited about their new addition to their plant collection that they immediately put them all alongside one another, without a period of quarantine. This can lead to the new plant inadvertently infecting the existing one.
6. Bacterial infections
Leaf spot is one of the most known signs of bacterial infection in houseplants. It can be easily mistaken for fungal infection since the symptoms are the same. This includes that it can result in your Monstera developing black spots.
Like fungal infections, wind, water, infected seedlings, tools, or even hands can spread bacterial infections.
7. Improper fertilization
When its soil has enough nutrients, your Monstera grows healthily. However, insufficient nutrients can mean slow growth which, in turn, can lead to black spots on the Monstera’s leaves.
This can also have other implications. For example, even if your Monstera is growing new leaves, you may notice that your Monstera leaves aren’t splitting. This could be a sign of low levels of nutrients in your plant.
At the same time, be careful, as excess fertilizers in the soil can burn your Monstera. It’s for that reason that it’s a good idea to fertilize your Monstera when it’s in its active growth season.
Why are the new leaves on Monstera Deliciosa turning black?
Moisture imbalance in the soil might cause the new leaves on your Monstera Deliciosa to turn black. This is why your first step should be to check if your soil is too dry or too wet.
Never let the soil become too dry, and be sure to water your plant thoroughly to avoid missing out on some portions. At the same time, it’s important to not overwater your plant. Instead, create a schedule on when to water your Monstera or do it on a need-to basis to avoid your Monstera leaves turning black.
Temperature stress can also cause new leaves of Monstera Deliciosa to turn black. Indoor plants are sensitive to any slight change in temperature, including that any sudden increase in heat can stress your plant. This can result in your Monstera having a new leaf that’s black.
If exposed to temperatures for a long time, the plant’s development can be affected, meaning that in addition to black spots you may also see slow growth, reduced photosynthesis, and later a non-recoverable plant.
How do you fix black spots on Monstera?
You can fix your Monstera depending on the cause of the black spots. Monstera is a sturdy plant and will eventually bounce back to its healthy state within no time. Give your Monstera all the attention it requires to be strong again.
A Monstera plant is said to be a tolerant plant. This means that while it may give you signs of unhappiness, it will likely later forgive you by returning to its healthy state.
If your Monstera has black spots, how you fix it will depend on the causes identified. With some careful investigating, you’ll be able to see your plant going back to its green color shortly. The following is what you can do:
1. Water in moderation
If you notice you may be overwatering your Monstera, remove it to drain the excess water from the pot.
Wash your pot thoroughly and add fresh high-grade soil for your Monstera to the pot. You could even need to change the pot entirely into a better pot for your Monstera. Consider adding gravel to the soil for quick drying and you can add holes in the pot to act as drainage for excess water.
In terms of how often to water Monstera, you basically need to water it when it needs it, not necessarily on a strict schedule you set for yourself. To do this, check to see if the soil is still wet before watering your Monstera. You can use your fingers (the top one to two inches of soil should be try before you next water it) or a hydrometer to check how dry the soil is.
And remember that black spots on your Monstera aren’t the only sign of overwatering. If you notice your Monstera leaves turning brown instead, this is also a good indicator that too much water may be the issue here.
2. Remove your Monstera from direct sunlight
Provide proper shade for your Monstera. For example, move it away from the window if you have placed it close to a window that gets direct sunlight.
Monstera requires bright indirect sunlight for it to grow healthily. Some people do, however, place them in low lighting. Monstera can grow in low light, but they won’t thrive well. There will be slow growth and it can result in your Monstera leaves turning black.
3. Increase humidity levels
Monstera does not thrive well in dry air. Instead, it requires medium to high humidity. Consider using a hydrometer to be sure if your house has enough moisture.
If your Monstera has black spots, you can invest in a humidifier to control the moisture levels in your home. At the same time, too much moisture in the air is not good for your Monstera and can even damage stuff in your house, so be sure to regulate the humidity.
And regulating the humidity in your house is not only good for your plants but can help improve your own health!
4. Pest control
Have you identified that insects have infested your Monstera? Sometimes it’s hard to see the insects because they are tiny and may go unnoticed.
Each pest has a unique way of damaging your Monstera. For effective pest control, you need to know the unique patterns the insects leave on the leaves. Here are the most common pests that can leave spots on your Monstera Deliciosa:
- Scales – These are common pests for houseplants and appear on plants like small raised bumps. They don’t look like insects because they don’t even have legs. They are mostly found on the stem and under leaves. They also produce honeydew and mold.
- Whitefly – They suck on juices from plants, leave honeydew on leaves, and spread disease. These tiny white insects are tough to control because they move in an army, fly off once disturbed, and move to another plant.
- Aphids – They are tiny insects that suck the juices off the leaves. They damage new leaves, spread plant diseases, and excrete a sugary honeydew that attracts ants and mold. They are brown, black, green, yellow, and red colors.
- Spider mites – These are relatives of spiders and scorpions, and they inhabit the undersides of the leaves and leave a noticeable webbing. Spider Mites are very tiny and leave dots on the affected leaves.
- Thrips -These are slender and active insects with fringed wings. They suck up contents from the plant. They can’t kill the plant, but they damage flowers and foliage. They can be very active and mobile, hence hard to control.
Eliminating all pests from your plants can be very challenging and almost next to impossible. This is because many of these insects can fly and find their next victim.
The best thing is to practice pest control. Here are some ideas to do so:
- Prune your Monstera’s affected leaves (dispose of correctly)
- Spray water to remove most pests and webs
- Using sticky traps
- Use of insecticidal soap
- Use of a lint roller
- Spraying Neem oil
- Spraying Horticultural oil
5. Eliminate fungal and bacterial infections
Bacterial and fungal diseases are hard to control, but they are preventable. If every other possible cause of the black spots has been ruled out, a fungal or bacterial infection is the last resort. The only method to fix this is to cut and remove the afflicted areas of the leaves.
This will effectively eliminate the fungus or bacteria that are causing the disease.
The positive side of fungal infections is that they can’t do too much damage to your Monstera if caught early. Your Monstera will go back to growing beautifully with green leaves if given the proper care.
The first step to preventing bacterial infections is to give your Monstera all the care it deserves. Here are ways to treat fungal infection on your Monstera:
- Fungicides – This is a type of pesticide used for controlling and preventing fungal infections. This is an effective way of eliminating fungus from your Monstera. This method uses synthetic chemicals.
- Neem oil – it’s effective for pest control and can also control fungus. Neem oil cannot kill the fungus that is already on the plant, but it can prevent new fungus from invading the plant.
- Horticultural oil – Horticultural oil is specially made for the control of pests. It can also prevent the spread of fungal infection by closing fungal spores in a plant. You can spray horticultural oil directly to the affected leaf on your Monstera.
- Insecticidal oil – This solution can control and prevent pests on plants. Insecticidal oil has also been approved to be used to control and prevent fungus from spreading.
6. Proper fertilization
It’s hard to know when your Monstera needs fertilizer or when you have put too much of it. This is particular because the telltale signs of this are similar to the other things that may be causing your Monstera to develop black spots.
Fertilize your Monstera every month during its growing season only to ensure it has all the nutrients it needs.
To avoid too much fertilizer in your Monstera soil, be sure to repot it annually. This will even help in replenishing the nutrients your plant receives to achieve a healthy Monstera. Repotting (transferring from one pot to another) also gives the roots more space to grow.
How do you fix bacterial leaf spots on Monstera?
The best cure for bacterial leaf spots on your Monstera is cutting all the affected leaves and giving the plant the chance to recover effectively on its own. Removing the damaged areas reduces the spread of disease to other leaves or plants.
Unfortunately, there is no effective chemical for eliminating bacterial infection in houseplants.
To make sure that the infection does not contaminate other plants, dispose of the diseased leaves correctly. You can burn the leaves or put them in a plastic bag, tie the bag tight and dispose of the garbage. You can also bury the debris under the soil, far away from your garden.
Use a copper fungicide to manage bacterial infections, although it’s not effective in fighting bacteria diseases.
To prevent bacterial infection from causing black spots on your Monstera, be sure to always:
- Avoid placing your plants close to a new plant for a period in case it’s bringing bacteria with it from the store
- Always disinfect your tools before, in the middle of, and after using them
- Disinfect your hands, especially when moving from one plant to the other
- Check if your Monstera has black spots regularly to catch and treat bacterial infections
- Repot your Monstera to give it fresh soil free from bacteria
- Clean thoroughly any pots you want to reuse
Will black spots on Monstera go away?
Unfortunately, the black spots in your Monstera will not go away. Because of that, the best thing you can do is cut off the leaves that have big dark spots. You can also trim the leaves with dark spots on the edges.
But the best way is to cut the damaged leaves at the stem to eliminate any spread of the spots if it has a disease or pest infestation. That way, if your Monstera leaves are turning black from an infection, this should help to ensure that the other green leaves remain healthy.
Should I cut off damaged Monstera leaves?
Yes, cut off the damaged leaves from your Monstera if they are damaged. That said, if your leaves have small dark spots on the edges, you can trim the leaves with scissors. Dead parts in a plant can encourage fungus and bacteria to spread since the virus thrives well on the dead plant cells.
Any dead part in your Monstera does not produce energy for the plant, so it should be cut off and, with time, new healthy leaves will grow.
If your Monstera has black spots, there’s no question that it looks unattractive. Removing the leaves with the black patches also helps improve your Monstera appearance and gives it a chance to grow healthy again.
Avoid cutting all leaves with dark spots if your Monstera has most of the leaves damaged. Plants need their leaves to photosynthesize, so you can leave some leaves uncut so that the plant continues to produce energy.
Bacteria infections can cause your stem to snap. If you notice any change in the stem on your Monstera, cut them off at the bottom to allow the plant to direct energy to other parts.