10 Reasons Your Monstera Plant Has Brown Spots

Does your monstera plant have brown spots on the leaves? There are a number of reasons why this happens, some of which are relatively harmless. In this article, gardening expert and houseplant enthusiast Madison Moulton looks at why brown spots may appear on the leaves of your Monstera, and what you should do next.

Gardener holding a monstera plant with brown spots on leaves

Monsteras are beloved houseplants, an impressive genus of interesting leaves and amazing patterns. As they are appreciated for their foliage, it can be distressing when that foliage begins to discolor and die off, indicating a serious growth problem.

So, if your monstera has started showing brown spots on the leaves of the plant, then it’s common to wonder what’s happening with your plant.

There are many reasons why your monstera may develop brown spots, from incorrect care to environmental conditions and pests and diseases. Take a look at these common issues to decide which is most likely and use the fix to resolve the issue.

Too Much Sun

Indoor plant with spots on leaves from sitting in sun. Behind the plant is rope lining wrapped around the support for the plant.
Too much sun can cause a number of issues, including spots on the leaves of the plant.

In their native habitats, monsteras climb up trees, shaded from the leaves of taller trees above. They typically receive dappled or filtered sunlight from above, enough for photosynthesis and further growth.

When grown indoors, the closest match to these native conditions is known as bright indirect light. These are areas close to bright windows but out of the path of any direct sun’s rays. As they are accustomed to shady conditions, any intense direct sunlight can lead to growth problems, including brown spots.

A sunburned monstera will develop brown patches on the leaves closest to the light source. These will be irregular and concentrated in the areas where the sun hit the leaves directly.

The leaves may also lose their green color, turning a ghostly white. The stems may begin to turn away from the light source to protect the plant from further damage.

The fix for this issue is simple – move the plant to a shadier spot. Simply shifting it out of the way of the direct light but still close to the window will help maintain growth. Prune any leaves with large brown spots to encourage new and healthy growth.

Overwatering

Overwatered plant has yellowing and browning on the leaf petals. The plant grows in a white plastic container with other plants around it.
Plants that are overwatered will show many signs, including brown spotting on their leaves.

Monsteras are hemiepiphytes, growing with the help of both soil and aerial roots. The plants need plenty of aeration and good drainage around the roots to improve oxygen movement and prevent fungal growth. If the roots struggle, the rest of the plant will too.

If you add moisture to the soil when it is still wet, the roots won’t be able to breathe. This excess moisture leads to fungal growth that can begin to attack the roots – a condition known as root rot. This can cause brown or black spots to develop on the leaves and stems as the rot spreads throughout the plant.

However, root rot in monsteras is not only caused by overwatering. It could also be the result of a lack of drainage in the pot or the soil. Extremely high humidity or overhead watering can also cause the same brown sunken spots if moisture is allowed to settle in parts of the plant.

Prevent root rot by only watering when the top layer of soil has completely dried out. If you suspect root rot, repot the monstera, trimming the affected roots to prevent further spread. Also avoid overhead watering and keep the leaves dry to stop more spots from forming.

Tap Water

Gardener watering a houseplant with a white watering can. There is dark potting soil in the container and the plant is growing quickly.
Using tap water can harm plants that have chemical sensitivities.

The next cause is also related to watering. But, instead of how much water the monstera gets, the root of the problem relates to what water you are using.

Monsteras and other tropical houseplants are sensitive to the chemicals in some tap water, particularly in dense cities. The chemicals used to clean the water can build up in the soil, causing the roots to ‘burn’ in the same way they would when overfertilized.

Root damage can cause damage further up on the plant. Leaves may begin to develop brown patches that become crispy and die off. If you cannot think of any other potential causes related to recent care, they are likely the result of prolonged use of tap water.

To fix the issue, start by pruning majorly affected leaves. Then flush the soil by rinsing with filtered or distilled water to prevent more build-up. Make sure you change the water you use, or alternate watering with tap water and filtered or rainwater to keep the soil healthy.

Too Much Fertilizer

Gardener with white gloves is fertilizing houseplant. The soil is being placed into the pot at the root of the plants.
Too much fertilizer can cause burns on the plant, as well as brown spots on the leaves.

Monsteras grow best when given the right amount of fertilizer once every few weeks during spring and summer. If your monstera is growing slower than usual, you may want to counteract the problem by fertilizing. Unfortunately, when used incorrectly, you will likely notice patches of brown developing on the leaves.

This happens for the same reason as the use of tap water – build-up of salts in the soil. These salts damage the roots, limiting their ability to function and displaying signs of a problem above the soil too.

Overfertilized monsteras need plenty of time to recover and return to normal growth. Flush the soil with filtered water until it runs clear and avoid fertilizing for several months. Overfertilizing is tougher to fix than under-fertilizing, so err on the side of caution.

Lack of Humidity

Plant with brown crispy leaves at the edges of the plant. The plant is dry and needs to be watered. Some of the leaves have water spots on them that have been dried, leaving a white residue.
A lack of humidity can cause a number of problems for these tropical plants.

Temperature and humidity are vital conditions to consider if you want to keep a monstera happy. Temperature is usually covered by keeping the plant indoors as they tend to prefer the same temperatures humans do. But humidity can be a little trickier to manage.

In their native habitats, humidity typically remains above 70%, sometimes going above 90% in the rainy season. Replicating this indoors if your climate is dry, can be a tough task. Unfortunately, if you don’t manage to raise humidity above at least 40%, your monstera leaves will begin to turn brown.

Lack of humidity typically causes the tips of the leaves to slowly brown, spreading inward as the problem worsens. These can eventually turn into large patches of leaves devoid of color, indicating a serious issue.

A humidity meter will quickly tell you whether this is the problem. You can raise humidity by placing the plant in a higher-humidity room, using a pebble tray, or misting a few times a day (although this can lead to fungal issues and more brown spots).

The most effective solution is to invest in a humidifier that will improve conditions for your monstera and all other tropical houseplants in your home.

Leaf Spot

Leaf spot on infected house plant has brown and black spots. The plant is dry and sits outdoors. There is a large dry area on the plant leaf surrounded by browning and yellow spots.
This common indoor plant disease is fairly easy to identify.

Leaf spot is a common disease among not just houseplants, but all garden plants. Different types of leaf spot have different causes, from fungal to bacterial. But, as the name suggests, these issues all lead to spots forming on the leaves. These often start out yellow, fading to brown as parts of the leaves and stem die off.

Fungal leaf spot is more common in monsteras and causes light brown soggy spots to appear on the leaves and stems. These leaves need to be pruned off the plant to stop the problem from spreading uncontrollably.

There are some treatments you can try to fix the issue depending on the exact cause, but majorly infected plants are typically better discarded to stop spreading to other plants in your home.

Rust

Plant with leaf rust. There are spots on the leaf that are yellow on the exterior with brown on the interior. The image is a close up, and you can see the serrations in the foliage of the light green leaf.
Rust is another fungal issue that causes brown and yellow spots.

Another fungal issue, rust is not common on indoor monsteras, but isn’t impossible either. Rust leads to patches of orangey-brown on the leaves and stems of the plant, typically clustered in the same area and spreading outward.

Quick treatment when rust is spotted is essential. This issue can quickly spread to other plants in your home or outdoors if not removed. Start by isolating the plant and cleaning any tools you have recently used on your monstera to protect your other plants.

Once isolated, treat the issue with neem oil or another fungicide designed for use against rust. Follow the instructions exactly to remove as much as possible. You may need to treat the plant several times before it is safe to bring back to its previous home.

Scale

Scale insects on the surface of a yellow houseplant leaf. The edges of the insect are up close, and you can see them attached to the leaf.
Scale insects are a common cause of several different indoor plant problems.

Brown spots are typically a sign of another issue on your monstera. But, in the case of scale, those brown spots are the problem themselves. These sap-sucking insects attach themselves to stems and even leaves, forming hard and armored bumps.

You may miss them at first glance, but once they reproduce and spread, scale infestations are hard to miss.

Again, start by isolating the plant. Follow up with treatments of neem oil or insecticidal soap, rubbing on affected areas to remove all the visible bugs. You will likely need to apply the treatment a few times before the pests are completely gone.

Spider Mites

Up close image of spider mites crawling on the edge of a plant leaf. The mites are small and red, and are crawling inside of a white web on the leaf of a plant.
A common houseplant pest, spider mite infestations will cause several symptoms.

Spider mites are one of the most common indoor pests, identified by their webbing left between leaves and stems. They may be hard to spot on larger monsteras, but with a closer look, you should be able to see these tiny pests crawling around.

Spider mites suck the sap out of the leaves and stems to sustain themselves. They leave behind small yellow patches of damage that eventually turn brown, expanding as the bugs settle in.

Luckily, the same treatment of neem oil or insecticidal soap applies to these bugs too. You can start by rinsing off the plant to get rid of any visible bugs and webbing, treating afterward to tackle those that remain.

Thrips

Plant with thrip damage up close with dak areas of the edge of the leaf. The visual is close up, and you can see the veins of the leaf, as well as the small serrations in the leaf pattern. Browning appears at the top of the area where the leaf converges.
Although they can be difficult to see, thrips can cause several problems, including browning foliage.

Thrips are much more difficult to spot on monsteras, although they are also less common than the other two bugs. These microscopic pests are typically white or black, crawling over the surfaces of your monstera leaves.

They are usually identified first by the damage they do, including wilting and brown or black spots on the undersides of leaves.

Use the same treatments previously mentioned to tackle thrips, pruning away heavily damaged leaves to allow the plant to recover. Make sure you inspect nearby plants for signs of thrips in case they have already spread.

Final Thoughts

Brown leaves are a concerning issue on monstera plants, especially rarer species that are difficult to find. But the good news is, that many causes of brown spots can be treated if you react quickly to the issue. Start by tackling the most likely cause and moving down the list until your plant recovers.

SHARE THIS POST
A large monstera plant with curling leaves growing indoors.

Information

12 Reasons Your Monstera Plant Has Curling Leaves

Curling leaves on monstera plants can happen for a variety of different reasons. The good news is, most of the issues that cause leaf curl are both preventable and treatable. In this article, gardening expert and houseplant enthusiast Madison Moulton examines why your monstera may have curling leaves, and how to fix it!

White Mealybug Crawling on Succulent Plant with Red Stems

Information

How to Get Rid of Mealybugs on Succulent Plants

If you've found mealybugs on your succulents, you don't need to panic. While these pests can cause damage, they aren't untreatable. In this article, gardening expert and houseplant enthusiast Madison Moulton takes you through six simple steps to rid your succulents of their mealybug problem.

African Violet With Leaves That Have Turned Yellow Sitting in Sunlight

Information

7 Reasons Your African Violets Have Yellow Leaves

Does your African Violet have yellow leaves? There are a number of different factors that can contribute towards this condition. The good news is, most causes are treatable, and preventable. In this article, gardening expert Liessa Bowen walks you through what to do when you start seeing yellow leaves on your favorite houseplant.

revive dying orchid

Information

5 Reasons Your Orchid is Wilted, Droopy and Dying

Do you have a drooping, browning, dying orchid plant? There are many reasons your ochid might be struggling. In this article, gardening expert Melissa Strauss examines the reasons your ochid may be dying, as well as how to revive it and bring it back to life.

calathea leaf curl

Information

9 Reasons The Leaves on Your Calathea Plant are Curling

Leaf curl is a common problem amongst calathea plants. The key is figuring out why it's happening, and then correcting the problem. However, prevention is also the best defense with these popular houseplants. In this article, gardening expert and houseplant enthusiast Madison Moulton examines the primary reasons leaf curl could be happening to your calathea plants, and how to fix it.

Close up of two different kinds of particles. The one on the left is white and rounded and the one on the right is sandy brown in color and rougher in texture

Information

Perlite vs. Vermiculite: What’s The Difference?

Trying to decide between vermiculate and perlite for your garden? It can be difficult to figure out which of these soil additives is better for your garden needs. In this article, gardening expert and former organic gardener Logan Hailey examines the differences between them, and the best uses of both.