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Monstera/Swiss Cheese Plant Leaves With Black/Brown/Yellow Spots

Monstera/Swiss Cheese Plant Leaves With Black/Brown/Yellow Spots

The Monstera plant, also known as the Swiss Cheese plant, is an attractive evergreen that grows large leaves with natural holes, hence the nickname.

Growing a Monstera plant does not require special treatment, but this plant does have problems with the plant leaves turning yellow or brown, as well as developing brown spots. They are usually caused by incongruent watering, poor nutrition, improper sun exposure, and temperature intolerance. 

Let’s look at some common reasons that your Monstera leaves can change colors and develop spots. You can reverse most of these problems without severe damage done to your plant. Here we go!

Monstera Plant Leaves Turning Yellow

Monstera Plant Leaves Turning Yellow

If your Monstera leaves turn yellow, it could be one of three problems: watering incorrectly, improper light, and malnutrition.

Watering

Yellowing leaves are typically a sign that you have improperly watered your plant. In addition to watering your plant properly, Monsteras do well if you clean the leaves with a soft microfiber cloth dipped in a cup of water mixed with a drop of dishwashing detergent. 

When the problem is overwatering, you will notice yellowed leaves that develop brown spots. There might also be mold growing on the top of the dirt and squishy stems.

But if your plant hasn’t been getting enough water, the leaves will start to droop and turn yellow. There might also be brittle brown spots. Over time, the leaves will begin to wrinkle and dry out.

Remove any leaves that have turned yellow or brown by snipping them at the base. They will grow back healthy as long as you water them appropriately.

To avoid improper watering your Monstera, wait until the soil is dry to the touch. Most gardeners only water their plants once a week. 

How to Tell When It Needs Water

To determine if you need to water your plant, test the soil one to two inches below the surface. You can use three different methods to do this:

  • Finger Test – The finger test requires poking your finger down into the soil, up to the middle knuckle. If the ground feels dry and there’s no residue on your finger when you remove it from the dirt, it’s time to add water. If your finger comes out streaked with dirt, or the soil feels wet, don’t add any new water. Recheck it in twenty-four hours. 
  • Stick – Another method you can use to test the soil is to use a stick, such as a chopstick or a skewer. Poke the stick down into the ground at least two inches. Examine the surface once you remove it from the dirt. If there’s nothing on the stick, it means the soil is dry and needs watering. If the stick looks discolored or has dirt sticking to it, there’s no need to add water. 
  • Moisture Meter – Some people like to use a moisture meter to determine if their Monstera plant needs watering. These devices can be found at any home improvement store or online and aren’t expensive. Most people won’t need to use a meter to tell when their plants need water. But if you do, it’s as simple as inserting the sensor in the dirt. If your plant needs water, the meter will read around three. 

How to Properly Water a Monstera

Now that you know how to tell when a plant needs water, let’s talk about how to water your Swiss Cheese plant. 

If you have a smaller house plant, you can water your plant by putting it in the sink and watering with the faucet. If your plant is too big to move, you can use a watering can. 

Add water to the soil until you see it draining out of the holes at the bottom of the pot. Empty the draining pan as soon as it fills up, as letting your plants sit in water can make the roots rot. 

When watering your plants, add the water to the soil and not on the top of your leaves. And be sure the soil drains easily and quickly. The dirt should not be compacted. 

If your pot does not have drainage holes at the bottom, it’s wise to drill some or layer the bottom two inches of your container with rocks, so the roots aren’t sitting in collected water. 

Improper Lighting

Another issue that can cause yellowing leaves is improper lighting. Monstera plants need a lot of bright or medium, but not dark, indirect sunlight. 

Letting your plants have too much exposure to direct sunlight can cause the leaves to scorch and turn yellow. Consider sunny rooms if your plants are indoors, or under large trees, if you’re planting outside.

Avoid areas where there will be direct sunlight around mid-day, when the sun is the harshest, as this can burn the leaves.

For your plants to thrive, consider planting them somewhere humid, if possible. But they will still grow in regular humidity as well. 

If you can’t provide adequate humidity levels, you can supplement by misting your leaves with a spray bottle after cleaning them to remove any dust or dirt debris. 

Malnutrition

The final cause of yellowing leaves could be malnutrition. Monstera plants need extra nutrients to grow a healthy green color and retain the holey, Swiss cheese appearance in the leaves.

Like most plants, Monstera needs a balance of nitrogen, phosphorus, and potassium (NPK). Most fertilizers contain these three minerals in a pre-mixed ratio, with numbers representing how much each vitamin there is in the mix.

For Monstera, you would need plant food providing a 5-2-3 formula, meaning five parts nitrogen, two parts phosphorous, and three parts potassium. We recommend Monstera Plant Food, which you can buy from Amazon. 

Many gardeners prefer to fertilize their plants with each watering, which can be done by adding a small portion of liquid plant food to your watering can. It is possible to use granulated or powder plant food as well, although liquid does better for Monstera plants.

Monstera Leaves With Brown Spots

Monstera Leaves With Brown Spots

Many gardeners have a problem with Monstera leaves that develop discolored brown spots. These spots could be dark or light brown and are indicative of different issues.

Light Brown Spots

If your Swiss Cheese plant has light brown spots, there are multiple reasons this could be occurring. Spotted leaves can be a sign of the following issues:

  • Dehydration
  • Sunburn
  • Root rot
  • Physical damage
  • Disease
  • Pests

Dehydration

Brown spots on your leaves are most likely caused by your plants not getting enough water. In addition to brown spots on the leaves, you’ll also notice that the leaves’ edges are starting to brown and dry out. 

Check your soil to see if it feels dry or use a moisture meter. In warm months, you might need to do more watering to your plant than in cold seasons. If the dirt feels dry, add some water. 

You will need to trim off any dead parts as they will not grow back after being damaged. Leaving your leaves with crispy, brown edges can cause your plant not to grow properly

Sun Damage

Leaves that are starting to dry out and develop brown spots can also be signs of too much sun exposure. Observe your plant throughout the day to ensure it is not getting direct sunlight, which can scorch the leaves.

If you think too much sun might be the problem, move your potted plants a bit further away from the window or switch to a room that faces a different direction. Avoid windows facing South as this could cause too much sun.

Using South-facing windows, cover the window with a sheer curtain, reducing the amount of direct light coming into the room. 

Root Rot

Root rot occurs when you overwater your plants. When your plants are developing spots due to overwatering, it can lead to severe damage to your plants if you don’t reverse the problem. To avoid root rot, perform proper watering techniques, as we’ve discussed earlier. 

To repair the damage from root rot, you must repot your Monstera. After carefully removing your plant from its current pot, use clean shears to trim off any rotted roots.

Roots that need trimming will have a mushy, squishy feeling and will turn a sickly brown. After you’ve clipped the roots, remove as much of the dirt from around the root ball.

You’ll also need to trim off any damaged foliage, so long as it doesn’t mean you’re left without any leaves. 

Fill your new pot (or the previous pot that you were using that has been thoroughly cleaned) with fresh, dry dirt and then add in your Monstera. 

Make sure when you put your plant in the dirt, that you don’t plant too far down, so your roots have room to grow. 

Water your plant using room temperature water, mixed with plant food following the watering recommendations we discussed earlier. 

Physical Damage 

Monstera plants do not like to be messed with, so touching the leaves to get a better look at how their growth can cause damage. 

You can also accidentally damage the leaves while moving them around or repotting. When your leaves have damage, it can lead to scarring. A small gash on a new leaf can turn into a giant mark once your plant grows larger. 

Unfortunately, there is nothing you can do to reverse the damage once it’s happened. However, in most instances, this damage will not hurt your plant or prevent it from growing. 

Use caution when cleaning or moving your plants, so you don’t end up with damage. And don’t force your leaves to open or split, no matter how long it takes. 

Your leaves will spread open when they are ready. Forcing them to open early can cause your leaves to experience irreparable damage.

Disease

Brown spots that have yellow halos, or circles, around the area, are usually a sure sign that you’re dealing with a fungus. 

Fungal issues arise when your plants stay extremely wet, and there’s poor air circulation. If your pot doesn’t have drainage holes at the bottom, that could be your problem. 

When you notice signs of fungal disease, it’s crucial to your plant’s survival to immediately address it. Use clean shears to remove any infected parts of the plant. 

To avoid fungal infections, follow proper watering techniques, and make sure your soil has adequate drainage. Keep the draining tray completely dry in between waterings. 

You should also avoid letting water get on the leaves. Water the soil only, and don’t mist your foliage until all signs of the fungus are gone.

Insect Infestation

The presence of some insects can leave your Swiss Cheese plant with lots of small, brown spots. Two common pests frequently found on Monstera plants are spider mites or whiteflies. 

Spider Mites

Spider mites are a common pest found on over 180 different types of foliage, including Monstera plants. They have the appearance of tiny spiders, hence their name. 

In cold climates, they spend the winter under the soil and become active and destructive during the summer. But in warmer areas, they can be active year-round. Hot, dry conditions make them the most productive. 

Spider mites damage your plants by extracting nectar and crucial nutrients from your plants using their needle-size mouths. In response to this feeding, your plants will start to develop black spots. 

Examine your plants once a month to check for insect presence. You should also check your plants any time you bring them in from outdoors. To prevent spider mite infestation, you can use a safe plant insecticide. 

Whiteflies

Whiteflies are a common pest found on indoor plants. These tiny flies collect on the underside of your leaves and feed off different parts of the plant. 

Your plant can suffer nutritional deficiencies and brown spots, but they can also be at higher risk of fungal diseases and other pest infections.

To get rid of whiteflies, many people use a vacuum to suck them off. You can also use a sticky fly trap that you can hang from the stake holding your plant upright. 

Insecticidal soap, a mixture of dishwashing detergent and water, can eliminate most of the adult whiteflies. Neem oil is also a plant-safe insecticide to use for the treatment of whiteflies. 

Monstera Leaves With Black Spots

Monstera Leaves With Black Spots

If your Monstera leaves are starting to develop black spots, it could be a sign of a few different problems. Let’s look at a few common causes of black spots on Monstera leaves.

Too Much Moisture on Leaves

Typically, leaves that have black spots mean that there is too much moisture on your plant. Although Monstera does great with misting, doing it too often can cause black spots.

These discolored areas are a sign of rotting, which happens when your plant gets too much water exposure. If left untreated, the rot could venture down the stem and into your roots. 

Once your plant has root rot, it’s tough to cure and may have to be thrown away. Avoid having your plants damaged beyond repair by limiting the amount of misting you do. 

If you’re not misting your plants at all and there are still black spots, it means there’s too much humidity in the room. 

Monstera can survive in as low as 40% humidity, although it flourishes better with humidity around 65%. If you have high humidity, there is no need to mist your leaves with water. 

Improper Temperature

Black spots can also be a sign of improper temperatures. Monstera plants are a tropical species, meaning they are cold-intolerant. 

If your plant leaves are breaking out with black spots, it could be that the room where you’re growing your plants is too cold. 

Even if you have a room with plenty of windows, the temperature can drop at night, especially if your air conditioning unit is set to low. 

Monstera plants prefer temperatures between 65°F – 85°F (18°C – 30°C). However, it should never get below 60°F. Otherwise, your plants can start to get black spots.

Dehydration

A lack of water can cause your plant to develop black spots on the leaves. If your soil is staying dry despite frequent watering, you could be dealing with your plant becoming hydrophobic. 

Hydrophobic means that your plant’s roots can no longer absorb water as there are gaps between the soil and the roots. Try watering your plants from the bottom up, by placing your pot into a pot of water, or your tub or sink. 

Wait until the soil at the top has turned wet before removing your plant from the water. If bottom watering isn’t doing enough to water your plants, you may have an issue with your roots not being rootbound.

Pull your plant from the pot and examine the roots. If the roots are curling around the root ball instead of extending into the soil, you may need to repot your plant into a larger container so the roots have more room to expand.

Final Thoughts

Monstera/Swiss Cheese Plant Leaves With Black/Brown/Yellow Spots

Monstera plants are a holey, evergreen plant that can grow to massive size. They do not require a lot of maintenance, although you do need to use caution when watering. These plants need a medium to bright indirect light, as direct sunlight can cause the leaves to burn.

Be aware that Monstera leaves are toxic to humans and animals, so you want to keep these plants out of reach for pets and young children. And always wash your hands after caring for your Swiss Cheese plant. Happy growing, my friends!