If your monstera has brown spots on its leaves. This means there is a serious problem with your monstera plant. In this case, you need to act fast if you want to save your lovely houseplant.

Fungal-bacterial diseases and incorrect watering sessions are the two main causes of monstera leaf spots.

Overwatering, underwatering, pest attacks, fungal diseases, exposure to extremely bright light, and fertilizer problems also cause dark brown spots on monstera leaves.

Today I will explain how you can identify the brown spots and what you can do to reverse your plant health.

Also, Why do even new monstera leaves have brown spots?

Below is the complete guide keep reading and make notes.

Let’s start:

Old monstera leaves naturally turn yellow, brown and fall off the plant. If old leaves are yellow and have brown spots on them.

No need to worry because it is a natural process of shredding old leaves.

But if the young leaves are infected then it is a sign of a serious problem.

Dark black and brown is the usual color of monstera spots. They do not have a particular shape. Small size spots appear when the problem is in its first stage.

Large dark circular spots mean the problem with your plant is serve and it is dying. But the good news is you can save your monstera by making a few changes in its care routine.

In less than 60% of the cases, you need to use fungicides. Most of the time monstera revives its health with minor tweaks.

Causes & Solutions of Monstera Brown Spots

Monstera plants are tropical rainforest plants. While growing at home you need to give them a growing environment like their natural habitat.

But as we all know it is not possible to turn a grow room into a rainforest.

But monstera needs the same natural environment to grow happily. So, people start experimenting with its care routine.

Some gardeners start giving more water, and some wait until the entire pot becomes dry. The secret of growing monsteras is they are able to adapt to indoor growing conditions.

But you need to give them good care. Following are the mistakes that trigger brown spots on monstera leaves.

Read carefully and identify the causes of brown spots in your case.

Pest Attacks

pest attack on monstera plants

Pest infestation is a common cause of brown spots in monstera plants. Aphids, mealybugs, thrips, and scales are the biggest enemies of monstera plants.

They live under the leaves and suck the plant juice to live and double their population.

The wounds they create on the leaves look like brown spots. 

To prevent this problem, you need to inspect your plant while watering. Closely check the leaves because leaves are the food for pests.

Solution

The best solution is to kill them with the most effective methods. Use a cotton ball and rubbing alcohol to wipe the leaves.

Isopropyl solution will kill them on the spot. Carefully and slowly wipe both sides of each leaf.

If a pest problem is at an advanced stage, then you should use insecticidal soap and rinse your plant.

This is very effective and will kill all the insects and pests. The only downside of insecticidal soap is it will make your plant weak for a few days.

Because the chemicals used in these soaps are highly potent. Sometimes the plant leaves become weak after the treatment.

The good news is this effect is temporary and your plant regains its health in 2 to 4 days.

Wrong use of Nutrients

For best monstera leaves and flowers, you must fertilize your plant with a balanced fertilizer.

Monsteras do well in nutritional potting soil. But you should only use fertilizers in limit. Overuse of fertilizers results in brown spots on monstera leaves.

Firstly, excessive fertilizer burns the plant leaves and as a result, leaves develop brown burned spots.

Secondly, the slats in the fertilizer start collecting at the base of the plant. Slowly they move towards the root ball, stick to it, and block the normal root function.

Solution

If you are sure that overuse of fertilizers is the cause of monstera brown spots in your case. Then immediately flush the soil.

Take the plant out of its pot and remove the soil from the root ball. Cut the infected root portion with a knife or shears.

Wash the monstera pot with dishwashing liquid and warm water. Dry it with a clean cloth and add fresh potting mix.

Plant your monstera in it and give some water to keep the soil moist.

Your plant will thrive in 5 to 7 days.

Repotting is the only solution to save over-fertilized monstera plants.

Stem Spots and Infection

Brown spots or bumps on monstera stems are caused by the excessive use of water on leaves. Warm and humid rooms increase the chances of this fungal infection. 

The second cause of stem infection is pest attack. If there are pests present on the stem then wipe them with a cotton cloth and neem oil.

It is hard to treat stem infections.

Solution

The best thing is to prevent this condition in your plants. To do so stop spraying water on monstera leaves.

  • Increase the air circulation in the room. Install a duct fan.
  • Isolate your plant
  • Use fungicide spray to clean the stems.

Your plant will revive if the stem infection is in the early stage. If it is already infected the entire stem, then it is better to cut it off and save other parts of the plant.

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Sunlight Exposure

brown spots on monstera leaves

Light is the main source of plant energy. It is required to turn water and nutrients into glucose (plant energy).

When we look at the natural habitat of monstera. There it grows under the canopy of large tall trees. There is no chance that direct sunlight can touch the plant.

In rainforests, monstera lives on indirect bright light.

This clears that your plant does not need direct sunlight. But sometimes we expose our plants to direct sunlight in order to full fill their light needs.

This practice is totally wrong in the case of monstera plants.

Sunrays are very sharp and they can burn the monstera leaf cells. These burned cells turned into brown and black spots.

Solution

The only solution to this problem is to change the location of your plant.

Do not place it on a sunny spot even if your plant is overwatered. As long as there is a draining hole in the pot no need to expose it to the sunlight.

The ideal place is where your monstera plant can get plenty of indirect bright light. 6 to 7 hours of indirect light is enough for this plant to make its food and grow healthy.

If you are using grow light for your plants. Then install it at least 20 to 24 inches above the plant.

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Fungal and Bacterial diseases

Fungal and bacterial infections are responsible for leaf spot diseases. Fungus infection bacteria start eating the leaf tissues.

As result, the leaves start developing small dark spots. Later these spots turn brown and form large brown spots.

Slowly the fungus spread to the entire leaf surface and all leaves turn brown and crispy.

Whereas in bacterial infection you see a number of tiny brown spots on each leaf. Bacterial infection is a little hard to treat.

Solution

To save your plant you have to identify the problem at the first stage. Then immediately separate your infected plant from other healthy plants.

For quick results use copper-based fungicides.

These fungicides are effective in fungal and bacterial infections. Generally, they are costly treatments but you can get the best deal on amazon.

Search online and buy a branded fungicide and bacterial solution. The follow the instruction of the product and your plant will thrive again.

Wrong Watering Methods

root rot in monstera

Watering houseplants is a technique that takes time to master. Every plant reacts differently when watered.

You must learn when your plant needs water and when it’s time to let the soil dry.

Overwatering results in root rot and damaged roots cannot supply sufficient water and nutrients to plant leaves.

This turns your plant weak and the foliage turns yellow and develops brown spots due to loss of water and nutrients.

Solution

The only solution is you need to learn to water monstera plants. Before watering them insert your finger into the potting soil to check the moisture.

If the top 2 inches of the soil are dry then you can water your monsteras. Otherwise, wait for 48 hours and let the top 2 inches of the potting soil dry.

This is the safe watering practice.

If the potting soil is releasing a foul smell, then repot your plant in new soil. Also, cut the infected roots in repotting.

Quality of Water

The quality of water also impacts plant health. Leaves are the first to show signs of bad quality water.

Filtered water is best for watering monstera plants.

Because such water does not contain heavy metals and also is free from chlorine and fluorides.

These two substances are often found in our tap water. When you use tap water for plants. Chlorine and fluoride get collected in the root zone and damage the roots.

We all know plants with damaged roots do not live for long.

Solution

Please use filtered water for watering houseplants.

Or

Fill the bucket with tap water 24 hours before the watering session. Let the bucket rest on the floor for 24 hours.

During this time the fluoride and chlorine sit at the base of the bucket and you can use the upper half bucket water.

For best results, if possible then collect the rainwater and use it for watering plants. You will see the difference in your plant health in just 2 watering applications.

Incorrect Temperature and Air moisture

Sudden change in the room temperature directly affects the health of monstera leaves. In hot weather, monstera leaves start wilting due to the loss of leaf water.

After then the leaves develop brown spots before turning completely brown.

Cold drafts also trigger brown spots on the monstera leaves. In botanical language, these spots are called chill spots.

In cold weather, the leaf cells start shrinking and turning brown.

Solution

Do not place your plant near the heating vents, air conditioner, and in cold winds.

To save its life and to reverse the brown spots change the place of your plant. Move it to a warm place. Do not allow the direct cold winds to touch the plant leaves.

To help your plant recover fast you must prune the affected leaves. This way your plant saves a huge amount of its energy.

Then spend this energy to grow more new healthy leaves.

Foliage Rust

Monstera is an ornamental plant and rust can cause brown spots on monstera leaves. Rusty spots are different in appearance from brown spots.

Rusty spots look the same as rust that you see on iron tools (reddish-orange).

Hot and humid weather is the best time for rust to attack plants. Increase the air circulation in the grow room to prevent this problem.

Solution

Stop overwatering your monstera plants and do not follow the overhead watering technique.

The first step is to grab sharp shears and prune the infected leaves. Do not remove too much foliage. After pruning use mild bleach to disinfect your tools.

If this practice is not enough to control rust. Then you should use Sulfur or copper-containing fungicides. Sulfur is more effective than copper fungicides.

How to prevent brown spots on monstera leaves?

Monstera brown spots are the result of a lack of care. You should follow the below guidelines to prevent brown spots in monstera plants.

In fact, the below tips will keep your monstera healthy and stress-free for years.

Only Indirect Light

Expose your monstera to indirect bright light only. Because the direct sunrays are hot and can damage the plant leaves.

Sunburn is the main problem that is popular with sun-exposed monsteras.

Indirect light is enough for monstera to perform photosynthesis. In extreme low light areas, you should use artificial grow lights.

Avoid Dehydration

Supply enough water to your plant to keep the soil moist for 365 days a year. Because monstera is large size houseplant. It needs more water than other houseplants.

Use chlorine and fluoride-free water for watering monstera. Also, make sure you are not overwatering your plant by checking the soil moisture level.

Safe Location

Place your plant pot away from heat vents and ac vents. As I mentioned above hot and cold winds damage the plant stem tissues.

This results in weak plants and a lack of nutrients. As a result, monstera leaves develop small brown spots.

Weekly Inspection

Check your plant closely once a week at the time of watering. Look for the signs of fungal and pest infestations.

Prune the yellow leaves and keep the plant pot clean.

Cut the infected leaves if any and dispose of them in the garbage bin. Do not use them in compost.

Start with Fertilize soil

Always use sterilized soil for growing monsteras. If you are using ready-to-use potting soil then no need to sterilize it.

Because commercial soils are already sterilized and free of pests and pathogens.

To increase the nutritional values of the potting soil. It is best to use organic fertilizer. If possible then use compost instead of commercial fertilizers.

Compost gives a regular supply of nutrients to the plant. Also, increases the water retention power of the soil.

Stop Top Water

Do not spray water on plant leaves as long as the humidity in the room is too low for the plant.

There are others humidity increasing methods like pebble tray or plant humidifier.

Too much water on monstera leaves + and warn climate increase the chances of fungal infection and bacterial infection.

Both the problems are hard to treat and can kill your plant if you do not know how to fix them on time.

FAQ

Should I cut monstera leaves with brown spots?

You should only those monstera leaves that are infected with fungal and bacterial diseases. If there are 3 to 4 spots on each leaf. Then no need to cut them.

On the other hand, if the problem is due to pests, then no need to cut the leaves. Get rid of pets and the leaves will regain their health.

Only cut those leaves that totally damaged or contain tiny holes.

Why do my new monstera leaves have brown spots?

If new monstera leaves come up with brown spots. This means the soil is holding too much water. stop watering your plan for a few days.

Use a pot with drain holes.

Unpot your plant and check the root conditions. If they are damaged, cut the damaged part and repot your plant in a pot by using fresh soil.

Conclusion

I hope now you understand what to do when monstera has brown spots on its leaves. Identify the cause, follow the solution and save your monstera plant.

Overwatering and damaged roots are the two primary reasons for monstera leaf damage.