Last Updated on April 13, 2022 by Admin
Philodendron plants are generally tough and resilient plants that are easy to care for. However, dark patches and brown spots on philodendron leaves can sometimes appear.
These are a sign of concern, so it is important to quickly identify the cause and treat the problem.
Why are there brown spots on philodendron leaves? Philodendron leaves get brown spots usually because there is a fungal infection.
Although too much direct light exposure, overwatering and pest infestation can also cause brown spots on leaves to appear.
In some cases, low humidity, root rot and too much fertilizer are the reason as well.
Causes of Philodendron Brown Spots on Leaves
Below are the main causes of brown spots on philodendron leaves. Note that there are a few reasons why this can happen. As such, you don’t want to just choose the most common one and use the treatment there.
Instead, use the list below to narrow down the cause to those relevant to what’s happening to your plant. Then use the solution for that specific issue.
Too Much Light
Philodendrons live under the canopy of the rainforest in Central and South America. Thus, while they do get light, the do not take the brunt of the sun’s rays directly.
As such, they do best under bright, indirect, filtered or dappled light. They will also grow well in medium and low light.
However, they cannot tolerate more than 2-3 hours of direct sunlight. This is especially true during the hottest time of the day and the year.
More specifically, 10:30 a.m. to 3:30 pm. and during summer.
When the light is too intense or they receive excess light, their leaves will initially turn yellow. Then you’ll see brown spots start appearing.
In extreme cases, the leaves will later on get scorched leaving you with burn marks.
How to Fix Excess Light
Excess light is easy to fix. However, the important part is figuring out that it is getting too much light.
And if you see brown spots on its leaves, you’ll want to check whether the plant is getting hit by the sun’s direct rays during the day. If it is at any other time than mornings, then odds are it is getting too much exposure.
Therefore, move the plant to a less bright spot.
A spot near an east facing window is ideal. Although you can place it in the west and south.
In both the latter ones, make sure to use a filter like blinds or curtains block out some of the sun’s rays if you want to keep the plant near the window.
Otherwise, try to keep the plant at least 3 feet from the south or west windows.
Another common reason for brown spots on philodendron leaves is overwatering.
In general, philodendron are good growers. Not only do they have a healthy growth rate, they will also reach a god size. If you let them climb up a pole or similar support, they will happily do so.
Also, because the plant comes from tropical rainforests, it is used to damp environments.
As such, it enjoys moist soil. But avoid wet and soggy soil.
Too much water will cause the roots to suffocate or make them prone to fungal infections. Both can lead to root rot. Additionally, you’ll see yellow leaves, brown spots and then brown leaves as well.
Thus, the best way to water your philodendron is to wait until at least the top 2 inches of soil has dried before adding more water.
You can use your finger and stick it into the soil to feel for moisture. Similarly, you can use a moisture meter if you prefer going with a device.
How to Fix Overwatering
The trick is to keep soil moist without leaving it wet. However, this is easier said than done.
When there is too much water, the roots will drown in the moisture as the soil gets waterlogged. This can cause brown spots in leaves not to mention other symptoms as well.
As such, always check the soil before you add water.
If the soil feels wet or even a little moist at about 2 inches below the surface, wait a couple of more days before adding water. Never add before the top 2 inches of soil has completely dried.
This will help you avoid overwatering.
Similarly, you can water from below by placing the plant in a large container or a bathtub with some water. The soil will then absorb the water through the drainage holes of the pot.
By taking water from below, the soil absorbs moisture on its own rate.
And you can take the plant out of the water once the surface feels moist.
Make sure to let the soil completely drain after that.
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Root rot is one of the most serious problems for your philodendron. And if not treated, it can eventually kill the plant.
So, it is important to know the symptoms of root rot. The earlier you spot it, the bigger the chance of saving the plant.
If you notice streaks of black or brown spots on philodendron leaves, you may want to check the root ball to see if there is root rot. This is a symptom that appears when root rot is present.
Once you take the plant out, you’ll quickly be able to tell if there is root rot.
First, there will be a bad smell even before you get close to examining the roots. That’s foul odor is of rotted roots.
The roots themselves will be black, soft and mushy, although not all will be rotted yet. If most are, there’s no saving the plant unfortunately.
On the other hand, you’re looking for white slightly translucent roots that are pliable yet a bit firm to the touch. These are the healthy roots.
How to Fix Root Rot
Root rot is difficult to fix because a lot really depends on the plant and its survival ability.
What this means is you can only help it up to a certain point.
But if too many roots have rotted, sometimes the plant is beyond saving.
In any case, there is no way to fix root rot. Instead, the goal is to save and revive the plant.
This is done by repotting it to a new, fresh potting soil.
To do so, unpot the plant then prune all the rotted roots. You’ll also need to prune the leaves with the brown spots.
Don’t forget to reduce the overall all size of the plant proportionally to the number of roots you took out. That’s because the new, smaller plant will be easier for the remaining roots to keep alive.
Before you repot, disinfect the entire root system by dipping it into a solution of hydrogen peroxide and water. Use 1 tablespoon of hydrogen peroxide for every cup of water.
You want the entire root system soaked to get rid of any possible pathogens. Also, clean the pot where the plant was in. You can use the same solution.
This ensures that if fungal infection was the cause of the root rot, it will not follow the plant.
Allow the roots to dry, then repot into a new container or the same one after it was disinfected. Use new, fresh soil that is dry.
Too Much Fertilizer
Philodendron plants need fertilizer to grow their best. But too much fertilizer will also case brown spots on leaves. Additionally, it can lead to fertilizer burn which can damage the roots.
As such, avoid using too much, too frequently or too high a concentration.
Follow the instructions on the label.
You can use a balance water soluble fertilizer diluted to half strength once a month during its growing season. Don’t feed in during fall or winter.
Alternatively, slow release pellets also reduce the risk of over fertilizing because they release the nutrients (and salt) over intervals. This decreases the amount of fertilizer applied each time and distributes it over a longer period.
How to Fix Excess Fertilizer
If you know the plant is suffering from too much fertilizer or suspect it, flush the soil using water.
To do so, run water to the soil for 5-10 minutes. You can use a low flow on the garden hose and rest it on the rim of the pot. Move the hose every so often to distribute the water on the soil.
This will allow water to carry the salts and excess minerals that have built up in the soil away with it as it drips down the bottom of the pot.
After 5-10 minutes, allow the soil to completely drain before you return the pot to its original spot.
You can do this every few months to reduce the risk of fertilizer burn due to excess salts building up in the soil.
The philodendron is native to the tropical rainforests of Central and South America. As such, it is used to high humidity. And it prefers 60% to 70% humidity. Although, it can tolerate 40% humidity as well.
But if you keep the plant somewhere with dry air with humidity that’s way below its desired ranged, the plant will not be happy.
And it will show this.
One symptom is brown spots on the philodendron leaves. You’ll also see brown and crispy tips and edges.
How to Fix Humidity Issues
The only way to fix low humidity is to increase it. But you don’t need to increase humidity in your entire home or the room where the plant is in. All you need to do is increase humidity around the plant.
Thus, my favorite free method is to use a humidity tray.
Just get a large tray that’s a few inches deep. This will let it hold water. Then place some rocks so that the top of the rocks is somewhat flat and above the water line.
Then put the plant’s pot on top of the rocks.
When the water evaporates, the vapor increases humidity around the plant. You don’t have to do anything else except refill the water once it gets depleted.
Of course, you can also buy a humidifier, mist the plant or move it to the bath room.
Philodendron are not overly prone to pests. But there are some bugs that like to attack them including mealybugs, spider mites and aphids. These are all dangerous because they can cause serious damage once they grow in number.
When they feed on the plant, the damage will initially produce certain symptoms among them brown spots on leaves. However, this will get bigger and you’ll end up with larger patches before the entire leave will turn brown and curl up.
How to Get Rid of Pests in Philodendron
If you notice pests like spider mites or mealybugs, the first step I always take is to spray them off with water. if you philodendron is still not too big you can use the sink.
But for bigger philodendron plants, you can take it to the bathroom and use the showerhead or go outside and use the garden hose.
Use a light stream but be thorough. The goal is to spray off the bugs as the water will remove them and carry them away from the plant.
This is a quick way to get rid of a lot of the bugs. But it may not get them all.
You’ll need to repeat every few days when you see more bugs. And it can take 3 to 5 times of spraying.
Alternatively, you can use an insecticidal soap spray or neem oil. It will usually take several weeks to resolve as well on a once a week application.
Another common reason for brown spots on philodendron leaves is disease. This is something that can happen even if you take proper care of your plant and give it everything it needs.
However, in most cases, excess moisture is usually the cause for disease.
This can be from watering too much or too frequently, wetting the leaves, watering later in the day, lack of light or air circulation to let the wet spots dry faster.
Brown leaves on philodendron leaves that are caused by diseased usually is accompanied by either yellow foliage or brown patches that grow along with it.
When this happens, it is very likely that your plant has an infection.
The two most common problems on this end for philodendrons are:
- Bacterial leaf spot disease
- Fungal leaf spot disease
With bacterial leaf spot, you’ll see brown spots with yellow halos around them. The spots will be irregularly shaped and they will appear as clusters on either side of the foliage.
The leaves will also turn yellow.
With fungal leaf spot, the brown spots appear on the surface of the leaf and are a bit spread out although they will blotch all over most of the foliage area.
The leaves won’t always turn yellow. And issue will spread to the stems as well.
If there is new growth, they will have brown blotches as well and soon die and fall off.
Again, both these diseases are caused by excess moisture. So, be mindful of how you water and how often you do it. Avoid leaving the soil and leaves wet.
How to Get Rid of Disease in Philodendron
First is let the plant dry out a bit first. You don’t want more water because moisture will encourage disease growth.
With bacterial diseases, you can prune the leaves. They will usually be localized to the affected leaves. So, once you remove these foliage and let the plant dry it should resolve in time.
With fungal diseases, you’ll also want to prune the leaves to limit the infection from spreading. But you’ll likewise need to apply fungicide spray to get rid of them.
To prevent disease from happening again, be mindful of how and when you water. Additionally, keep the plant in a well-lit location with good air circulation. Both will help any wetness dry faster to avoid infections.