Plants aren’t able to whine or complain when they don’t feel good. However, that doesn’t mean that they’re not communicating. Brown spots can be an early warning that something in your Philodendron’s environment isn’t quite right.
The primary causes of brown spots on Philodendron leaves are:
- Too much sunlight
- Lack of humidity
- Root rot
- No air circulation
- Leaf spot
There are subtle differences in the spots and in the behavior of your plant and soil that can make it easier to identify what the cause may be. Keep reading to learn more about the causes – and solutions – of brown spots on your Philodendron leaves.
What Causes Brown Spots on Philodendron Leaves?
Too Much Sunlight
Though you might associate tropical plants like the Philodendron with a lot of sunlight, for the majority of tropical plants on the shorter side, that isn’t the case. Think about a jungle. Though it is sunny outside, the jungle is usually well shaded by the canopy of trees above. The plants under those trees tend to live in a lot of shade.
That’s where these Philodendrons live in their natural habitat. Though they like being near the sun, they don’t ever want direct sunlight. Instead, they do better in sunny areas without direct sun, or even dimly light areas.
Brown spots, tips, or burned areas on the leaves getting direct sun could be an indicator that the plant is in too much sun.
Simply move your plant to an area with lower light levels. If some leaves have died or are in the process of dying, you can cut them off as well, so your plant isn’t wasting energy on trying to keep them alive.
To best mimic the tropical area they naturally live in, keep them in the shade of other plants. You can also use a light mulch to keep the soil cooler and reflect a majority of the light it receives.
Overwatering is a common problem with many plants, and the Philodendron is one of them. Initially, when a plant is overwatered, the leaves will begin to droop. If the problem persists, then your Philodendron will also begin to develop brown spots.
While overwatered and underwatered Philodendrons start off looking the same with droopy leaves, the brown spots are a clear sign of overwatering.
Generally, Philodendrons only need to be watered every one or two weeks. Usually, once a week is enough in the summer and spring, and in winter and fall, they can be watered as little as every two weeks. However, based on other conditions, this can change, so always check the soil moisture levels before watering again.
Before watering your plant, always test the soil moisture level. You can do this with specific tools designed to read the levels, or you can simply stick your finger into the soil and see if any of the soil is moist or clings to your finger.
If it does, the soil is likely still too wet to water. When you do go to water your plant, Philodendrons do best with the soaking method. This just means you take your pot and fully submerge it for a few minutes in water so the roots can soak up what they need.
Just make sure your soil can drain properly afterward.
If your soil has the incorrect pH or nutrient level, then you may find your plants are developing brown spots and blemishes on the leaves. Leaves lower to the soil may also look yellow and wilted. Philodendrons do best with a pH of around 5.0 to 6.0.
To fix an over-fertilized plant, the most important step is to halt fertilization until your plant is looking healthier.
Then, you need to begin the process of removing the excess fertilization. If you see any visible fertilizer, try to remove it. Also, replace the first couple of inches of soil with new soil. If your Philodendron needs watering soon, pour water over the top to help rinse out the fertilizer rather than soaking it.
If it doesn’t seem to be working, repotting with new soil is another option.
Once the problem is fixed, you must prevent it from happening again. Philodendrons only need to be fertilized once a month in the spring and summer, and every two months in the fall and winter.
Using a slow-release fertilizer can also help to make sure your plant doesn’t receive too high of a concentration.
Lack of Humidity
Remember that these are tropical plants, and therefore need a lot of humidity. If you live in a drier state, you may not be able to easily achieve this indoors. Your Philodendron will begin to show signs of stress, which commonly leads to small brown spots on its leaves.
Mist your plant regularly with distilled or filtered water or place a humidifier in the room. In addition, make sure to dust your plants, as dust can block moisture absorption by the leaves.
If your plant stays overwatered for a long time, or can’t drain properly, it may begin to develop root rot. If a Philodendron starts to develop root rot, the leaves will be covered in dark brown spots.
To confirm whether the cause of the spots is root rot, pull your plant out of the soil and look at the root ball. If you’ve never looked at the roots before, what you should be seeing are white and crowded roots that are firm to the touch.
If the roots look brown and feel mushy, then it is highly likely you have root rot.
When your plant is suffering from root rot, the best solution is to remove all of the bad roots with scissors or pruning shears and replant the Philodendron in a new plot.
Since root rot is caused by a fungus, you want to use fungicide or diluted bleach (one part bleach to three parts water) to clean the new pot and the roots. Everything that touches the roots, including the scissors or shears, should be cleaned using this method.
Use a new soil mix as well, as the fungus can continue lurking in the soil, plotting its return and eliminating any success as a result of your efforts.
No Air Circulation
If your plant doesn’t get enough air circulation, bacteria and other germs can begin to host on the leaves of your plants. This likelihood increases with plants like the Philodendron, which can benefit from frequent misting or spraying to keep them humid.
The best solution is to create little air pockets in the soil when you water your plant, using chopsticks or a similar tool. Additionally, you can place the plant in an area that is exposed to low-intensity air circulation.
Insects can cause injury and stress to your plant which leads to brown spots on Philodendrons.
Common pests include: Aphids, Mealybugs, Scales, and Spider Mites.
These all leave various forms of brown blotches and spots on the leaves, and small bugs may be present on the underside of the plant’s leaves.
If you catch it early enough, you can quickly prune the leaves that are hosting the pests. Once it becomes more widespread, however, using neem oil and insecticides on the underside of the plant works best.
Leaf spot is caused by both a fungus and bacteria. Brown spots associated with leaf spot will often look like sunken patches, and sometimes cankers will grow on the branches. Sometimes, the brown patches will look burned, be uneven, and have yellow halo patterns as well.
The best solution is to trim the leaves that are infected. If you can identify the difference between bacterial and fungal leaf spot, you may be able to provide more specialized treatment.
Fungal Vs Bacterial Leaf Spot
What Does Fungal Leaf Spot Look Like?
Brown spots will appear on the surface of the leaves. These spots will grow as time goes on. Even new growth will have spots and will usually die off quickly. These are usually just plain brown without a halo or a red tinge and may cause a sunken area on your leaf where the brown is present.
What Does Bacterial Leaf Spot Look Like?
Bacterial leaf spot tends to present as brown and red spots that are almost translucent. These spots are irregularly shaped and tend to have faint yellow halos surrounding them. It may almost look like your plant is burnt in spots.
They will often form in clusters on certain leaves.
How Do You Treat Fungal Leaf Spot on Philodendrons?
There are fungicides readily available that you can add to the leaves or soil and that can help to eradicate the fungus.
It is best to do this immediately after you start to notice signs of fungal leaf spot, in order to have the best chance of eliminating it.
Also, half a teaspoon of baking soda to one gallon of water is said to help with fungus. You can apply this to the leaves themselves, on both sides, to help your plants.
How Do You Treat Bacterial Leaf Spot on Philodendrons?
It is worth noting that this is a very contagious disease. As soon as you notice a plant has it, you need to isolate it from the others.
Next, remove any leaves that have signs of infection. A solution containing two tablespoons of baking soda and a drop of dish soap to a gallon of water can be used on small areas where there are signs of infection.
Keep a close eye on your plant and trim new infections as they pop up to increase the chances of your plant surviving.
Should I Cut Brown Leaves off My Philodendron?
It is always a good idea to cut the brown leaves off of your Philodendron. Not only does this make your plant look nicer, but it allows your plant to focus its energy and nutrients on new growth and flowers.
Plant leaves that are in the process of dying can be cut off to allow your plant to not waste its time trying to bring them back to life. Generally, when you water your plant, you should also go ahead and cut off any leaves that you may notice are dying.
There are many reasons why a Philodendron might have brown spots on its leaves. Some are easy to fix, with simple solutions such as moving the plant out of the direct sun or putting it in a place with better airflow. However, sometimes brown spots may be a sign of a more serious condition like bacterial or fungal leaf spot.
The primary causes of brown spots on Philodendron leaves are: too much sunlight, overwatering, over-fertilization, lack of humidity, root rot, no air circulation, pests, and leaf spot.
Learning the subtle differences between the various potential causes of brown spots, and which signs are warnings of more serious problems, is important if you want to cultivate a healthy, happy Philodendron plant.