6 Reasons why Monstera Leaves are Turning Brown

Monsteras are easy-to-grow indoor plants that will fill any corner of your home with a gorgeous touch of greenery. Their lovely, large green leaves help to brighten up your interior. However, you might be wondering why your monstera leaves are turning brown and how you can prevent this.

Monstera leaves can turn brown for a number of reasons. These mainly include inconsistent watering, too much direct sunlight, and incorrect applications of fertilizer. In addition, monstera leaves can turn brown as a result of temperature extremes as well as insufficient humidity in the air.

Let’s look at all of these reasons and discuss how they can be avoided.

Inconsistent Watering

Both over and underwatering can cause your Monstera leaves to turn brown, as this can damage the roots of your plants. Plant roots are vitally important as they transport water and nutrients from the soil up to the green parts of the plant. Therefore, it’s vital that you give the roots the right amount of water and nutrients to keep your plant nice and healthy.

Overwatering can Lead to Root Rot

Overwatering your Monstera can cause all sorts of problems at the root level. If the soil is consistently wet, the roots of your plant aren’t able to get any oxygen, and this will eventually cause them to die.

Plant roots need both water and air to remain healthy. When the soil is continuously wet, all the air pockets that would normally exist will be filled with water. This means that the roots aren’t able to breathe and will eventually suffocate.

In addition, constant moisture around the roots can attract fungus growth. Primarily, this will be the root rot fungus that is quite often fatal for plants. Once the roots have been infected with this fungus, there’s very little that you can do to save the plant.

For this reason, it’s important to ensure that you avoid overwatering your plant at all times.

How to Determine if your Monstera is Suffering from Too Much Water

Common signs of overwatering include:

  • The presence of brown spots on the leaves
  • Your plant looks wilted even though the soil is wet
  • Even the stems of your Monstera are turning yellow or brown
  • The surface of the soil in the pot is wet, and you may notice mold growing

How to Fix Overwatering Problems

Firstly, you want to ensure that the pot your Monstera is growing in has plenty of drainage holes so that any excess water can easily drain out of the soil. You also want to make sure that the soil that your Monstera is growing in is free-draining and does not stay waterlogged after you have watered the plant.

Follow these steps to fix your overwatering problem:

  • Take your Monstera out of the pot and remove all the soil from around the roots.
  • Have a look at the roots and trim off any that look diseased, damaged, or brown and mushy. You can use a clean pair of secateurs to do this.
  • Next, you want to disinfect the roots with a solution of 3% hydrogen peroxide and water. Make up the solution by mixing one part of the hydrogen peroxide with three parts of water.
  • Lay the plant on some newspaper in a cool and dry spot for around six to eight hours.
  • Clean and sterilize the pot if you will be reusing it and fill it with a clean, free-draining potting mix.
  • Refrain from watering your plant for at least a couple of days.

Underwatering can Dry Out your Plant

On the other end of the scale, if your plant doesn’t receive enough water, it will simply dry out and die. As you would imagine, this will result in the leaves turning brown.

As is the case with many different types of houseplants, getting the watering right is vitally important for the health of your plants.

Conduct a Soil Moisture test

The best way to determine when you need to water your Monstera is to do a soil moisture test. This is simply a case of pushing your finger into the soil for around an inch or two.

If the soil feels completely dry and no soil is sticking to your finger, then the plant needs water. On the other hand, if the soil still feels quite moist and there is damp soil sticking to your finger, then you should refrain from watering and check the soil moisture again in a couple of days.

If you don’t fancy poking your finger into the soil, you can use a popsicle stick or chopstick instead. Alternatively, you might want to invest in a moisture meter that will accurately measure the moisture content in the soil.

It’s also important to note that your Monstera will require less frequent watering in winter than it does during warmer weather.

Keep a Watering Calendar for your Houseplants

For most people who grow indoor plants, it can be difficult to remember when it’s time to water. To make things easier, you might want to keep a watering calendar.

You can mark on the calendar when you watered your plant and then set a date (around two weeks later) as a reminder to check the moisture level in the soil to see if you need to water again.

Watering indoor plants should never be done on a set schedule because the temperature and rate of growth of your plants will always determine whether the plants need to be watered or not.

At least, if you keep a calendar, you’ll know when you last watered your plant and can then decide whether it’s time to check the moisture level in the soil.

Too Much Sunlight

While Monsteras don’t want to live in the dark, too much bright direct sunlight can easily burn the leaves of your plant, turning them brown. Monstera plants grown outdoors in more sub-tropical regions usually grow happiest when they receive some shade. Therefore, you want to mimic similar conditions when growing your Monstera indoors.

Your plant requires a fair amount of bright light, but this should not consist of direct sunlight. You see, too much sunlight will burn the leaves, while not enough light will result in smaller leaves that may also turn brown.

How to Give Monstera the Right Amount of Light

In order for your Monstera to thrive and grow, here’s how to ensure that it’s getting the right amount of light:

  • Try to put your plant near a west or east-facing window. This will ensure it gets plenty of bright but indirect light.
  • If the only spot you have available is near a south-facing window, move your plant further away from the window (around 5 to 6 feet).
  • Cover your window with sheer curtains, as these will filter out the direct sunlight.
  • During the warmer weather, you can give your plant a spell outdoors but make sure that you put it in a shaded spot.

Fungal Diseases

There are a few common fungal diseases that may infect your Monstera and cause the leaves to turn brown. These include anthracnose and eyespot disease.

How to Spot if your Monstera Have a Fungal Disease

Common signs of a fungal infection include:

  • The leaves exhibit brown spots that have a yellow halo or border around them.
  • The leaves have reddish-brown spots on them.
  • Other areas of the leaves may appear faded and even have white patches.

How to Deal with Fungal Disease on your Monstera

One of the best ways to deal with any fungal disease on your Monstera is to remove all the infected parts of the plant. This will immediately stop the disease from spreading. This is very helpful if only one or two leaves are affected, as these can easily be removed.

However, if your plants seem to have a more heavy fungal infection, you might want to make up a spray using baking soda and water. To do this, add one teaspoon of baking soda to one quart of water. Spray this all over the plant and let it dry.

You also want to ensure that there’s plenty of airflow around your plant and that the air is relatively high in humidity.

Constant Temperature Changes

Monstera is a tropical plant. Therefore, it prefers warmer temperatures somewhere between 68 to 86 degrees Fahrenheit (20 to 30 degrees Celsius). If the room where your monstera lives experiences sudden changes in temperature, it can cause the leaves to turn brown.

A drop in temperature and exposure to cold conditions causes damage to the cells that are within the leaves, much like if you try to freeze lettuce. This also means that you should never place your Monstera in direct line with an air conditioner as the cold air will cause damage to the leaves.

Additionally, windows can get quite cold in winter, and your Monstera will not like sitting in front of a cold window.

How To Ensure Your Monstera Is Not Exposed To Constant Temperature Changes

Ultimately, you want to ensure that you keep your plant in a warm room, especially during winter. It’s also important that you keep your Monstera well away from both heating vents and air conditioners.

Lack of Humidity

As already mentioned, Monsteras are tropical plants. Therefore, they’re used to a fair amount of humidity. For your Monstera to thrive in your home, you want to ensure that the air around your plant is relatively moist. Monsteras generally require a humidity level of around 50 to 60 percent.

This can be a problem during winter when your heating is constantly on because this can dry the air out quite significantly.

The reason these plants need a moist environment is that when conditions are dry, the plant will transpire through the stomata in the large leaves. This not only means that your Monstera will require more frequent watering, but it will also cause the leaves to turn brown, become dry and eventually curl up and die.

How to Increase the Humidity around your Monstera

There are a few simple things that you can do to ensure that your Monstera has the humid environment that it needs to thrive.

  • Invest in a humidifier that you place near your Monstera and other tropical houseplants that you may have.
  • Move your Monstera into another room that is higher in humidity, such as the bathroom or the kitchen.
  • Fill a shallow tray with pebbles and half-fill with water. Place your Monstera on top of the pebbles. The water in the tray will increase the humidity around your plant as it evaporates. In addition, the pebbles will ensure that the base of the pot is not sitting in the water. This protects the roots from becoming waterlogged.
  • If you don’t have an issue with fungal diseases, you could also consider misting the leaves with water on a daily basis.

Too Much or too Little Fertilizer

Not getting the fertilizer mix right can also cause your Monstera leaves to turn brown. Too much fertilizer can result in a build-up of salts in the soil. This will eventually burn and damage the roots. Once the roots are damaged, they cannot supply the plant with water or nutrients.

On the other hand, too little fertilizer may mean that your plant isn’t getting the right amount of nutrients. More often than not, this will usually first show up as a yellowing of the leaves before they turn brown.

How to Fix a Problem Resulting from too Much Fertilizer

If your plant is suffering from an overdose of fertilizer, the simple thing to do is to flush the excess salts out of the soil. To do this, take your plant to the sink or outside and flush the soil with water until the water runs freely out of the drainage holes.

After you’ve flushed the soil, you should not fertilize your plant for at least three months.

To avoid this problem, either feed your plant with a slow-release fertilizer only once a year or give it a half-strength solution of liquid feed once a month during the active growing season.

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