Brown Spots on Philodendron (Causes, Solutions, and Prevention)


Indoor philodendron leaves showing brown spots

Philodendron is one of the most forgiving, easy-to-grow plants which is why it is often recommended to newbie plant enthusiasts. 

Fuss-free attitude is their second name yet, like other plants, they are also susceptible to brown spots when kept in an environment not suited to them. 

Philodendron develops brown spots due to fungal infection. Too much light and overwatering are also common causes for brown spots on philodendron. In addition, Insect infestation, excess fertilizer application, low humidity or root rot can cause this common problem.

Let me walk you through various reasons for brown spots on philodendron. But before that it is important to understand what exactly these “brown spots” look like. 

Brown spots refer to dark brown patches on the leaves – sometimes in the center, sometimes at the edges spreading towards the direction of tips.

If the brown spots keep developing and are not dealt with at sight then the new growth (leaves) developing brown spots is inevitable.

Causes of Brown Spots on Philodendron Leaves 

Excess light

Philodendrons thrive in medium to low light settings because they are tropical plants. They are always shielded by larger plants and trees in the tropical forests. 

In a home setting, they prefer medium to low light. In other words, it thrives in part sun.

Philodendrons under excess light will initially have leaves turning yellow. Eventually, the foliage will begin developing brown spots. 

How to Fix

Place your philodendron, be it the trailing variety or the upright ones, near an east- facing window.

This is an ideal spot because while the sun may shine on the leaves, it will be only for a short period of time.

The intensity will also be much less than in the west or south-facing window which can result in brown spots on the leaves.

Excess water and water quality

Philodendrons are generally vigorous growers. They like to be moist at all times. But, given their resilient nature, they prefer drying out between watering. 

The general rule is to check the top oil by sticking in your finger by at least an inch deep. If your finger does not have any soil sticking then it means it is time to water. 

Normally, the foliage of a philodendron will droop if it is under-watered and has dried out.

But when along with the droopiness, the leaves begin to show brown spots, then it is a clear sign of excess water. James Wong of BotanyGeek, a London-based botanist, deems overwatering as the number one killer of houseplants. (Source: The Guardian)

The quality of water is also crucial for the health of philodendrons. Normal tap water consists of sodium and chlorine in large numbers.

This can cause salt buildup in the potting mix resulting in brown spots appearing on the foliage. 

How to Fix

Remember, philodendrons love staying moist but not wet. The leaves will start developing brown spots if your plant sits in water for an extended period of time.

This is because excess water causes the root ball to become waterlogged. In this scenario, it is not unusual for the new growth to display brown spots.

The key is to follow the “Less is more” approach. This means under watering is far better than overwatering. It is best to avoid watering with a water hose or running tap water on your plant in your kitchen sink.

Instead, you can place your plant pot in a tub filled with water. This way the roots of the plants get soaked and suck in only as much water as they need. 

Philodendrons love rainwater or distilled water. But not everyone has access to it.

If you give tap water to your plants then you should always let the water sit in the container with the lid open for at least a day.

This is for the chlorine and sodium to dissipate from water. This step is crucial for avoiding salt buildup that can cause brown spots on the stylish foliage of the philodendrons. 

Since overwatering can be fatal for your plants, it is also important to understand the result of waterlogged plants ultimately cause brown spots on leaves.

Root rot

When your philodendron keeps producing leaves streaked with brown spots, in spite of getting appropriate light and water, then it is time to inspect the root ball.

Sometimes, while the top soil appears to be bone dry, the root ball could be thoroughly wet. 

Ideally, the roots of a healthy philodendron should always be glistening white. Philodendron roots prefer being a little cramped and the plant shoots up aerial roots as well.

But brown, mushy roots show a possible root rot and are the prime reason for the growing number of brown spots on the foliage. 

Something to remember is the drainage holes in the pot. Make sure your plant is in a pot with enough drainage holes because you do not want it to sit in a pool of water.

It is not uncommon for soil to stick in the drainage holes, making it difficult for water to drain.

How to Fix

While it is difficult to save a plant with a mushy mass of roots, philodendrons are resilient plant species. They are an invasive plant variety of the tropical regions.

To revive it, it is very important to wash off the old wet soil and also get rid of the rotted root system. Snipping the leaves with brown spots is equally important to prevent further damage.

Then all this beautiful mess of a philodendron needs is some fresh, moistened potting medium. Within a few weeks, it should perk up and send up new growth.

The new growth is a clear sign that the roots have established and are doing well underneath the soil. 

To prevent root rot, you can also remove the plant from the pot and check the drainage holes. In fact, you should inspect the plant soil, roots and the bottom of the pot at least once a year.

Fertilizer 

Smaller size of leaves on a philodendron is its way of telling you that it needs a fertilizer with macro- nutrients. But some fertilizers are too strong for philodendrons and have adverse effects on the plant.

They result in brown spots on Mother Nature’s beauty. This includes liquid fertilizers as well. Additionally, too much fertilizer can cause the same problem

How to Fix

Slow- release pallets are an excellent alternative to liquid fertilizers. Plus they go a long way because they slowly release the nutrients as and when the plant needs them. Similarly, organic fertilizer is another great alternative.

Ideally, philodendrons need fertilizer every month from spring to summer and sparingly in fall and winter, about every six to eight weeks.

Humidity

Being tropical plants, philodendrons prefer humid conditions which can be a challenge to maintain indoors.

Additionally, dust accumulating on the leaves may further hinder them from accessing moisture in the environment. This ends up having brown spots and tips on the leaves. 

How to Fix

Misting the leaves once a day provides enough moisture. It is also a good option for plant owners who end up overwatering their plants. Regular misting will also stop the leaves from the developing brown spots and tips. 

Other ways for raising humidity levels include keeping a tray with pebbles under the plant pot and regularly misting them, using a humidifier or simply keeping several plants together at a spot.

But make sure your philodendron is not consistently in a wet condition because it can only serve as a breeding ground for pests. 

In a favorable humid environment, your philodendron leaves will be spotless and back to being their shiny selves!

Pest infestation

Philodendrons are not much prone to pests in comparison to other houseplants. Being vigorous growers, they can sometimes get dust mites. They can also get spider mites on the underside of their leaves.

Spider mites can cause more damage because they damage the plant cells in an attempt to feed themselves.

And this may result in brown spots on the leaves – and these spots can grow continuously until the entire leaf curls up and become brown. 

This article goes more in-depth about the causes and solutions of philodendron leaves curling.

How to Fix

Dust mites are easy to deal with. Spraying the leaves with water and wiping them off should do the job. Regular misting and wiping individual leaves on both sides should keep dust mites from appearing all together. 

For spider mites, you can make a solution of 3 parts water and one part dish cleaning liquid. Applying it on the leaves and wiping them off should keep them away. Spraying Neem oil on the leaves and stems is also helpful.

Two diseases common to Philodendron family

Imagine everything being fine and you are taking care of your philodendron like a pro. But you still see brown spots appearing regularly.

If the leaves wilt quickly, turn yellow on a frequent basis, or new growth appears with brown patches, then it is time to investigate for the two diseases philodendrons are most susceptible to. 

Below is a breakdown for the causes behind, symptoms of and prevention and treatment measures for each.

1. Philodendron Bacterial Leaf Spot Disease

Causes:

  • Microorganisms infect the leaves
  • Wet and cool conditions promote this bacterial disease.
  • Bacteria divide and reproduce therefore it quickly spreads. 

Symptoms:

  • Brown spots with yellow hues
  • Irregularly shaped spots 
  • May appear in clusters on the top or underside of leaves
  • Leaves turn yellow

2. Fungal Leaf Spot Disease

Causes:

  • Pathogens that cause it can come into contact with the foliage through wind, rain, or contaminated soil
  • High moisture is an ideal condition for fungus to thrive.

Symptoms: 

  • Brown spots occur on the leaf surface 
  • Spots spread and blotch most of the leaf
  • Leaf does not necessarily turn yellow
  • A visible progression from leaves to stems and roots or vice versa
  • New growth marked with brown blotches and dies soon.

Prevention And Treatment of the Diseases

⦿ Maintain a temperature of at least 70°F(21°C)

⦿ Adopt watering from the bottom to avoid the risk of overwatering. 

⦿ Ensure Philodendron stays pest-free

⦿ Isolate the sick philodendron 

⦿ Immediately separate the infected leaves from the plant to prevent it from spreading, while cleaning the pruning tool with a water and bleach solution.

⦿ Use bactericides to treat bacterial leaf spot

⦿ Use a copper fungicide to curb fungal growth

⦿ Do not prune excessively at one time – spread it over a period of time. Wounds are from where bacteria and fungi enter any plant

How to Prevent Brown Spots on Philodendron Leaves

Philodendrons adapt to their environment, be it the trailing variety or the upright ones, and it is this no-fuss attitude that makes them such a low maintenance plant. But the above-mentioned diseases can be detrimental to overall plant health and need attention as soon as they appear.

Here are some easy ways to maintain optimum health of your philodendrons. By following them you can keep the brown spots away from the incredibly beautiful foliage of your philodendron plants. 

⦿ Reduce overhead irrigation- top-down watering always has a risk of overwatering.

⦿ Give your philodendrons a drink early morning so that they have the entire day to get recharged and soak up the sunlight to initiate photosynthesis. 

⦿ Use terracotta pots for they are porous and absorb excess water in the soil. This could prevent root rot from overwatering in the long run which means prevention of brown spots on the leaves. 

⦿ Repot, if needed, only before or during spring. Never repot at other times of the year as this can send the plant in shock and shoot up brown-streaked leaves. 

⦿ Always mist leaves and wipes them with a paper napkin or a cloth. This way, the leaves benefit from the humidity, and wiping them clears up the dust which keeps dust mites away. 

⦿ Prune your philodendrons frequently. This is not only known to make those vines or climbers bushy by producing new growth but also strengthens the plant to fight infestations. 

⦿ Pay close attention to the size of leaves and the space between them. Small leaves and wider space between leaves on a vine indicate a lack of light. While philodendrons are low light tolerant, they will grow extensively in bright light. 

⦿ Rotate your pot every month for even growth. Vines always reach for light and leaves always face the direction of light. Therefore, rotating helps ensure that the plant is growing from all sides. 

⦿ If using liquid fertilizer then always dilute it with water before feeding it to the plants to avoid causing a burn which results in brown spots. 

Final Words

All in all, Philodendron is a tough plant variety that is not so easy to kill. While it can survive in any condition, it will thrive in ideal conditions, and with its sprawling display of beautiful leaves (some varieties have gorgeous variegation), it has the potential to give you tropical vibes!

Arifur Rahman

I'm the owner of gardenforindoor.com. After completing my bachelor of science in agriculture, I'm serving as a civil service officer at the Department of Agricultural Extension, Bangladesh. I started Garden For Indoor to make your indoor gardening journey easy and enjoyable.

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