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In this post, I will discuss why pothos plants get brown spots and how to address this problem. Pothos plants often get brown spots on their stems and leaves due to unfavorable growing conditions like extreme temperatures, humidity and light, and excessive applications of water and nutrients.
Insect pests and fungal and bacterial diseases also commonly cause brown spots on pothos plants. This problem can usually be solved by improving the growing conditions and treating any diseases that may be affecting pothos plants.
Pothos (Epipremnum aureum) is a hardy, low-maintenance plant species that rarely has brown spots when grown in favorable conditions. However, when grown in unfavorable conditions or infected by diseases, pothos leaves and stems sometimes develop unsightly brown spots.
Common causes of brown spots on pothos plants include:
- incorrect watering,
- too much direct sunlight
- fertilizer issues
- bacterial diseases
- fungal diseases
There are many ways to deal with the problem of brown spots on pothos plants. The affected parts of the plants are usually removed and discarded. If the cause of the problem is poor environmental conditions, it is critical to provide the appropriate temperature, light, and humidity levels for the pothos plants.
Brown spots on pothos plants can also result from poor maintenance practices such as incorrect watering. In these cases, you can remedy the problem by giving your plants adequate but not excessive amounts of water.
Over-fertilizing is another common practice that causes brown spots on pothos plants. The solution to over-fertilizing is to wait a few weeks before re-applying fertilizer (at 50% of the previous applications).
Insect pests also cause brown spots on pothos plants (usually on the upper side of the leaves). If the damage isn’t too severe, the brown spot problem can be solved by quarantining the plants, cutting off damaged plant parts, and eradicating the insects with an organic insecticidal spray.
If fungal or bacterial diseases are causing brown spots on your pothos plants, the problem can be usually be solved if diagnosed early.
A typical protocol involves quarantining the plants and removing affected leaves and stems, followed by an appropriate anti-fungal or anti-bacterial spray.
Insect and disease issues are themselves often caused by poor growing conditions. Improving the environmental conditions and implementing correct maintenance practices usually help address insect and diseases issues and resolve the problem of having brown spots on your pothos plant.
How To Identify Brown Spots On Pothos
Brown spots are easy to identify on pothos. Healthy pothos plants don’t have any spotted markings, so brown spots are starkly visible when they develop on the leaves and stems. In most cases, brown spots affect pothos leaves more than other parts of the plants.
The spots have a rounded (but not perfectly circular) shape. As the name implies, brown spots are usually brown and, depending on the cause of the problem, range in color from light grayish-brown to dark brown.
Causes Of Brown Spots On Pothos
Pothos plants can get brown spots for multiple reasons. Let’s look more closely at the most common causes of brown spots on pothos.
Incorrect watering is probably the most common cause of brown spots on pothos plants. Pothos plants are hardy and tolerate dry or waterlogged soil for brief periods. However, the plants suffer if under-watering or over-watering continues for too long.
It’s far easier to cause brown spots on pothos plants by over-watering than it is by under-watering them. The brown spots aren’t caused by the water but by the diseases that often result from repeated over-watering.
The problem starts when there is too much water in the soil. The excessive moisture stresses and weakens pothos plants because it starves their roots of oxygen, and the root tissues become soft.
At the time, over-watering also creates the ideal anaerobic conditions for fungal and bacterial pathogens.
These pathogens easily infect the roots of stressed and weak pothos plants, eventually causing diseases that are visible in symptoms like brown spots on the leaves and stems of the plants.
Too Much Direct Sunlight
Pothos plants are damaged easily by direct sunlight. When pothos plants receive direct sunlight that is too intense, they develop light brown spots and burned tips on their leaves.
The brown spots appear on the upper sides of pothos leaves that are most exposed to the light and can cover several inches of the leaves.
Pothos leaves get brown markings when exposed to direct sunlight because the leaves can’t photosynthesize and respire fast enough to process the sunlight. As a result, leaf tissue cells die, leaving the leaves with unsightly brown, scorched-looking markings.
If your pothos plant has brown spots on the leaves due to excessive direct sunlight, position the plants in indirect sunlight.
Finding a location with the ideal amount of indirect sunlight will depend on your latitude, climate, season, and the orientation of your indoor growing space.
Excessively low humidity in the air is a common cause of brown spots on pothos plants. Pothos plants prefer medium to high relative humidity levels due to their tropical origin, so they are easily damaged if the relative humidity levels in the growing area are too low.
When relative humidity levels drop below about 50%, pothos plants lose moisture rapidly to evaporation and can become dehydrated (even if the soil is moist). This often happens during winter in indoor growing environments.
A clear symptom of insufficient humidity is that pothos leaf tips start to become brown and shriveled.
If low humidity is causing brown leaf-tips on pothos plants, increasing the humidity levels near the plants will address the problem. To increase humidity levels, use a humidifier, or place a tray with water and small pebbles underneath or near the pothos plants.
Pothos plants also get brown spots from high humidity, though this problem is relatively rare. When humidity levels are above 90% for prolonged periods, pothos leaves are unable to transpire properly.
The reduced transpiration causes excessive moisture accumulation in the plants and creates favorable conditions for fungal and bacterial disease.
These fungal and bacterial diseases are primarily responsible for the brown spots that often develop on pothos leaves and stems in conditions of extremely high humidity.
The solution is to decrease the humidity levels in the growing area and address the diseases using the appropriate methods such as quarantining and anti-pathogenic sprays.
Temperature extremes can also cause brown spots on pothos. Brown spots are most commonly a result of cold temperatures, as pothos is a tropical plant that prefers a warm growing environment between 65F and 75F.
When the temperatures drop below 50F, pothos leaves start developing brown patches that spread over the entire leaf. If the cold temperatures persist, the leaves turn black and die.
To address the problem, remove the damaged leaves and increase the temperature around the plant. Either reposition the plant in a sunnier, warmer spot or use artificial heating to warm the temperature in the growing area. If you use heating, take care not to dry the air out too much.
Though less common, excessively high temperatures can also cause brown spots on pothos plants.
Brown, scorched markings develop on pothos leaves when the growing environment is above 35F for extended periods, or when the leaves are in contact with a windowpane or exposed to intense direct sunlight.
To address brown discoloration caused by extremely high temperatures, move pothos plants to a more favorable spot with lower temperature and light levels. If necessary, place containers with ice water around the plants to create a cool micro-climate for them.
Applying incorrect amounts of fertilizer can cause brown spots on pothos plants. Giving pothos plants too much fertilizer is the most common fertilizer-related cause of brown discoloration (because the plants have relatively nutrient requirements).
Signs of fertilizer damage on pothos plants include leaves with brown, burned lips and margins, and large, brown patches toward the center of the leaves. Pothos plants are also prone to manganese toxicity which appears as yellowish-brown spots on the leaves.
If the over-fertilizing problem isn’t too severe, brown leaf markings on pothos plants can be addressed by waiting at least a month before considering re-applying fertilizer.
Remove damaged leaves and water the plants regularly to flush excess fertilizer from the soil, and remove the damaged leaves.
When re-applying fertilizer to the pothos plants, it is advisable to apply fertilizer at half the strength of previous applications.
Under-fertilizing is a less common cause of brown markings on pothos plants. When pothos plants receive insufficient fertilizer, they develop nutrient deficiencies that result in brown, burned leaf tips and leaf margins.
Applying small amounts of general-purpose dry or liquid fertilizer to pothos will usually address the nutrient deficiencies causing brown spots on the foliage.
Insect pests can create brown spots on pothos plants, though Epipremnum aureum doesn’t generally have pest problems.
The presence of insect pests on pothos plants is usually the result of poor growing conditions and incorrect maintenance practices like over-watering.
The pests that most commonly create brown spots on pothos plants include:
- spider mites,
Spider mites cause tiny, round, gray, or white-brown spots on pothos leaves. These minuscule insects are red or orange and are barely visible on the undersides of pothos leaves.
However, the presence of spider mites on pothos plants is easy to identify by the characteristic leave damage and spider-like webbing the mites create.
Scale is a dome-shaped insect that ranges in color from black to brown and orange. This insect pest also creates leaf spots when it feeds on pothos sap.
The spotted markings caused by scale are whitish-brown or gray and are slightly larger in diameter and more irregularly shaped than those caused by spider mites.
Thrips are another insect pest that can cause brown spots on pothos plants when feeding on the sap of the plants.
These tiny, winged insects are light brown and congregate on the undersides of pothos leaves. Thrips create light-brown, gray, and black spotted clusters on the top of pothos leaves.
If the pest problem is identified early enough, it can usually be solved by quarantining the affected plants, removing damaged leaves, and eradicating the pests with a mild pesticide spray.
In most cases, this with be sufficient to deal with pests that are causing spotted discoloration on pothos leaves.
Leaf Spot Diseases
Many different fungal, bacterial, and viral pathogens cause leaf spot diseases on pothos. These microbial pathogens feed on the sap and tissue of pothos leaves, which damages the leaves and creates unsightly spotted markings.
Depending on the pathogen in question, leaf spot disease appears as spots ranging from white to gray, brown, and black. The center of the marking is usually much lighter than the borders, which are generally dark brown or black.
Leaf spot diseases often result from excessive moisture in the soil and when pothos leaves get wet. Lack of airflow compounds the problem of excessive moisture, making conditions more conducive to the development of leaf spot diseases.
The general strategy for treating leaf spot diseases on pothos plants is to isolate the affected plants from the growing area. Once quarantined, gently remove the affected leaves, and spray the plants with a mild concentration of an appropriate type of pesticide.
Bacterial Leaf Spot
Bacterial leaf spot disease causes brown spots on pothos plants. The disease often develops when pothos leaves get soaked with water or when the soil is water-logged.
The excessive moisture creates ideal conditions for bacteria like Pseudomonas cichorii to infect the plants and cause leaf spot disease (www.extension.psu.edu).
Bacterial leaf spot disease on pothos leaves usually appears as light brown spots with yellow borders. If the foliage keeps getting wet and the disease progresses, the markings join together to create large whitish-brown patches on the leaves. In drier conditions, the spots remain small, and they turn reddish-brown (www.hgic.clemson.edu).
When leaf spot disease is severe, affected pothos plants might need to be discarded. However, if the disease is detected early enough, the plants can be saved by removing diseased leaves and ceasing overhead watering. Placing the plants in a dry location with high airflow will also help the plants recover.
Fungal Leaf Spots
Fungal diseases can cause leaf spots on pothos leaves (www.edis.ifas.ufl.edu). As with bacterial leaf spot disease, factors that lead to fungal leaf spot disease on pothos plants include water-logged soil, wet foliage, and insufficient airflow in the growing area.
Leaf spots caused by pathogenic fungi species appearon pothos leaves as light brown dots with yellow borders. As the disease progresses, the spots merge and form tiny black dots. Eventually, fungal leaf spot disease causes pothos leaves to die back.
Fungal root rot diseases can also create brown spots on pothos leaves. For instance, pothos can be susceptible to infections by Phytophthora nicotianae, a type of water mold that causes a root rot disease called Phytophthora.
While Phytophthora and other fungal root rot diseases infect the roots of pothos plants, they cause brown markings on the leaves. In the advanced stages of the disease, these brown markings turn black, and the leaves eventually die.
Treating pothos plants affected by fungal leaf spot disease involves quarantining the plants, removing the damaged leaves, and spraying the plants with a mild organic fungicide.
When the plant has recovered, place the plant in a location with bright indirect light and adequate airflow, and void over-watering the plants.
Anthracnose is a common fungal disease that causes discolored markings on pothos plants. The disease is caused by several different genera of fungi, including Colletrotrichum andGloeosporium (www.ipm.ucanr.edu). Pothos often develops anthracnose when growing conditions are excessively moist and lack adequate airflow.
Pothos plants affected by anthracnose disease develop light brown leaf spots that turn dark brown followed by black. These leaf markings also grow and spread across the leaf surface as the disease progresses.
When left untreated, anthracnose will kill the affected leaves and, eventually, the whole plant will die.
If your pothos plant has anthracnose, follow the same general protocol for treating fungal disease in pothos plants. Isolate the diseased plant, remove the damaged leaves, and spray the plant with a low concentration of organic fungicide.
If the pothos plants recover from their anthracnose infections, ensure to place them in an area with sufficient airflow and indirect light. Try to avoid creating excessively moist growing conditions. Do not give the pothos plants too much water, and don’t get the foliage wet.
Rust is also a common fungal disease that causes brown markings on pothos plants. A wide variety of different fungi cause rust (www.rhs.org.uk). This fungal disease often starts in overly moist growing conditions.
Rust disease on pothos starts as small light-brown flat spots that turn into yellowy-orange or red bumps called pustules (depending on the specific fungal species), which are the spore-releasing parts of the fungus.
Severe cases of rust will result in pothos leaves turning yellow and falling off, and the entire plant may eventually die.
To address rust disease on pothos, implement a standard fungal treatment regime. The first step is to quarantine the diseased plants, remove damaged leaves, spray fungicide, and wait until the plants show signs of recovery. Lastly, ensure proper growing conditions when returning the recovered plants.
How To Prevent Brown Spots On Pothos
Preventing brown spots on pothos is straightforward and can be achieved by ensuring a favorable growing environment and appropriate maintenance practices.
By providing an optimum environment and using correct maintenance practices, you can support the health of the plants and keep them looking beautiful and free of blemishes.
The optimum growing environment for pothos plants includes:
- indirect light,
- warm temperatures,
- medium to high humidity,
- adequate airflow,
The growing location should provide pothos plants with exposure to bright indirect sunlight.
Pothos plants also need a warm growing area, so the temperature should ideally range between 65F and 75F. Relative humidity levels should be roughly 55% to 75% to keep pothos plants healthy.
Pothos plants need sufficient (but not excessive) air movement in the growing area to provide carbon dioxide and decrease the chances of fungal disease. Keeping the growing area free of dust and decomposing plant matter will also help to prevent fungal and bacterial diseases.
Pothos plants also require appropriate care to prevent brown spots from developing on the plants. Appropriate maintenance practices include:
- correct watering,
- appropriate fertilizer applications,
- leaf cleanliness.
Provide pothos plants with enough to keep them healthy, but be careful not to over-water the plants. The soil should be slightly moist most of the time but it’s advisable to let the top layer of the soil dry out somewhat before giving the pothos plants more water.
Ensure that pothos plants receive adequate fertilizer to meet their physiological needs. Due to their low nutrient requirements, over-fertilizing pothos usually poses a greater risk than under-fertilizing. Fertilizer should be applied infrequently and in low doses to avoid burning the plants with excessive nutrients.
Keep pothos leaves and stems clean by wiping them regularly with plain water or a mild solution of water and hydrogen peroxide or apple cider vinegar.
Maintaining clean leaves will help prevent dust accumulation and diseases from affecting the health of pothos plants.
Frequently Asked Questions
I’ve discussed most of the vital information you need to identify and treat brown spots on your pothos but there’s always more to know. Here are answers to some questions people frequently ask about pothos plants.
Why Does My Pothos Have Brown Spots On The Stem?
Diseases and pests are the most common cause of brown spots or markings on pothos stems.
Fungal diseases like anthracnose and rust can cause brown spots on pothos stems. Bacterial wilt disease also causes the stems of pothos plants to develop dark brown markings that eventually turn black and cover the stem as it dies. These fungal and bacterial diseases often result from over-watering.
Insect pests can also cause brown spots on pothos stems. The insects feed on pothos stems resulting in brown, irregular-shaped markings. Some insects like mealybugs and scale also create residues that appear as brown spots on the stems of pothos plants.
Poor growing environments and incorrect maintenance practices are generally the initial sources of the insect pests and diseases that cause brown spots on pothos stems.
Ensuring a favorable growing environment and applying appropriate amounts of water and fertilizing will usually solve the problem of brown discoloration on pothos stems.
Should I Cut Off Brown Spots On Pothos?
It is advisable to cut-off pothos leaves and stems with brown spots, though this depends on the severity of the problem. If you only see a few tiny spots that are not spreading rapidly, there might be no need to remove the affected leaf or stem.
If the brown spots or markings are rapidly expanding, remove the entire leaf or stem. After removing the affected parts of the pothos, implement appropriate remedial measures to solve the cause of the brown spots.
How To Tell If Your Pothos Is Dying?
You can generally tell if your pothos is dying when you see one or more of the following signs:
- severely stunted growth,
- drooping leaf and stem posture,
- dark brown or black markings on leaves and stems,
- leaves are dropping off.
However, the signs that a pothos plant is dying can vary depending on the cause of the problem, so it’s necessary to carefully inspect the plants so you can diagnose the problem correctly.