Monstera sunburn can affect the plant’s leaves damaging them and leaving them unsightly.
When this happens, you’ll see yellow or brown leaves, browning of the leaf edges and tips as well as dark spots on foliage.
Unfortunately, the damage isn’t limited the aesthetics only.
That’s because plants rely on leaves to absorb sunlight which plays a vital role in photosynthesis.
So, a sunburn monstera with many damaged leaves will negatively affect its growth, make it weak and prone to illness, pests and diseases.
What are the signs of monstera sunburn? Excess direct sunlight or full sun exposure are the most common reasons for monstera sunburn. Very dry soil and hot temperatures also contribute to.
This causes brown leaf edges and tip, discoloration, bleaching and dark spots on the foliage.
Therefore, it is important to keep the plant away from the sun’s direct rays as much as possible.
What Causes Monstera Leaves to Sunburn?
Monstera sunburn is primarily caused by excess sunlight exposure. However, there are other things can cause it as well or make the plant more prone to it.
As such, I’ll go through the different things you need to know about sunburn in Monstera plants.
This way, by avoiding these conditions, you’ll be able to prevent potential sunburn from damaging the plant’s beautiful leaves.
Too Much Light
As mentioned majority of the time, monstera sunburn is caused by excess light.
Here, there are two things at play.
One is the intensity of the light. Second is the duration.
Both play a role. Although, intensity often dominates the two. That’s said, a slightly high intensity coupled with long durations can likewise cause sunburn in monstera plants.
As such, with monstera sunburn, there are a few lighting conditions you want to avoid.
Ideally, monstera plants like bright, indirect light indoors and partial shade outdoors. This is because they are native to tropical regions.
But while there’s a lot of hot sun in both Central and South America, the plant primarily grows in the rainforests.
There, its size, while big, is no match for the huge trees that tower overhead.
Therefore, the trees provide the Monsteras with shade. This is why there prefer indirect or filtered light indoors and partial or semi-shade outdoors.
It is also why they cannot tolerate more than 1-3 hours of direct sunlight indoors or full sun outdoors. They are just not used to the kind of intensity from lots of direct sunshine.
That said, you can gradually acclimate the plant if you wanted to.
This is why monsteras get sunburn with lots of exposure to strong, harsh or intense light.
Indoors, this means it is important to avoid direct sunlight. More importantly, you want to keep it away from the sun’s rays during the hottest times of the day and the hottest times of the year.
These are 10:30 a.m. to 3:30 p.m. daily. And during the peak of summer.
Outdoors avoid full sun.
In many cases, growers will take their monsteras outdoors during the spring and summer to get a bit of a tan. This is great for the plant as it enjoys bright light.
However, when you do, make sure it does not end up under the sun’s scorching rays. Otherwise, it will experience sunburn which will destroy its leaves.
Underwatering, especially dehydration is another reason for monstera sunburn.
Monsteras like water, although they cannot tolerate wet soil.
However, the plant enjoys consistently moist conditions because it is used to the rainforest environment.
As such, then left dry, it becomes prone to sunburn and leaf discoloration.
You’ll also notice then when they lack water or get thirsty, they’ll be more aggressive.
Thus, a monstera left if very dry soil or that’s dehydrated will develop brown, dry, and crispy leaf edges and tips.
This is where the damage begins.
You’ll also see the browning extend inwards and later cover entire leaves if the problem is not treated.
Additionally, dry, light brown spots or lesions will start showing up on its leaves.
Another common reason for sunburn leaves on monstera plant sis fertilizer burn. Some will call these chemical burns due to their cause, which are the excess salts contained in commercial fertilizers.
This occurs when you overfertilize the plant.
It is one reason why growers will always warn people never to overfeed their plants.
In concept, more fertilizer may seem better. But there’s a hidden danger, the salt in the fertilizer mix.
So, when you feed your monstera with more fertilizer, you end up not just giving it more nutrients but also more salt.
The problem is as salt builds up in the soil, it will dehydrate the root system.
Salts, as most of you know, drawn moisture. This makes difficult for the roots to absorb enough water since the water is attracted to the salt particles instead.
What happens then is that the roots cannot absorb as much water as they need. In the process, this also limits the nutrients they’re able to take in.
The lack of moisture and nutrients eventually cause the “sunburned” browning and damage in your monstera’s leaves.
So, technically, it is not burning from the sun. Instead, it is caused by the excess salts and minerals in the fertilizer product.
This is why it is never a good idea to feed your monstera more than it needs.
In general, it does very well with a balanced liquid fertilizer with 15-15-15 or 20-20-20 NPK ratio.
Apply this houseplant fertilizer once a month during spring and summer and stop around early to mid fall. Then start over next spring again once the weather is warm and the plant starts growing.
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Extreme temperatures are likewise a no-no for monstera plants. And while it may sound ironic, the you may notice monstera sunburn due to extreme cold.
The ideal temperature for monstera plants is between 60 and 85 degrees Fahrenheit.
Because of its tropical roots, it also does not mind hotter conditions up to 95 degrees Fahrenheit. However, you do want to be more careful as you go above its ideal range because heat can cause more water loss.
The plant prefers a more moderate to warm climate condition because it lives under the shade of the larger trees.
So, while it can get very hot (over 100 degrees Fahrenheit) in the tropics especially during summers, the plant prefers conditions that are more moderate.
More importantly, since there is no winter or even cold months in the tropics, it cannot withstand the cold.
This is why it is important not to get temperature drop under 50 degrees Fahrenheit around your monstera. Some growers will be more mindful keeping their plant at least 55 degrees Fahrenheit or higher.
The colder it gets below this threshold, the higher the risk that its leaves will experience “sunburn”. You’ll see browning and a scorch-like color and texture like the leaves were “burned” by too much heat.
But this was actually caused to excess cold or leaving it in a cold place for too long.
On the other hand, while it isn’t as prevalent because the plant can tolerate more heat, monstera sunburn can like wise occur due to excessively high temperatures.
In this case, heat injury is the culprit.
And you’ll see brown leaf tips and edges develop as well.
Certain diseases can likewise cause the monstera sunburn effect. Again, there is no actual burning of its leaves due to the sun.
Instead, it is the diseases causing the leaf discoloration that makes them look like they’ve been scorched by excess heat or light.
In this case, the culprit is usually some kind of leaf spot disease.
And you’ll be able to tell as there will be brown spots with yellow rings around them that develop.
If you see these browning, it is caused by fungal infections.
Fungal problems on leaves of monsteras happen due to excess watering, too much misting or very high humidity.
It is the excess moisture that makes the damp environment conducive for fungi to grow and spread.
Therefore, you can cut down on watering and let the plant dry a bit. Or you can aerate it by leaving the plant somewhere with good air circulation.
Using a fungicide works just as well.
To avoid this from happening again, avoid overwatering or wetting the leaves when you water or mist the plant.
How to Treat / Save a Sunburn Monstera
So, what do you do if your plant experiences monstera sunburn?
Below, I’ll go through the different treatments and fixes you can do so save a sunburn monstera plant.
Not that you don’t have to do all of the fixes.
Instead, apply those that are relevant to what the cause of the leaf damage is.
Move the Monstera from Direct Sunlight
If monstera sunburn happens due to too much light, the one thing you need to do to save the plant is to move it away from the strong light.
Note that this light can mean different things.
Outdoors, it usually means too much exposure to the sun’s rays. In most cases, leaving the plant under full sun or an area where it gets direct sunshine exposure especially during the middle of the day.
If this is the case, move the plant to a partially shaded location that is well-lit.
Indoors, monstera sunburn will often happen from excess intensity of direct sunlight.
Usually, this means exposure near a south facing window which gets the brunt of the hottest times of the day. But it can also happen near a west facing window.
In this case, move the plant to a location with lots of light but where the sun’s rays will never touch the plant the plant.
A more hidden danger are grow lights.
Artificial lights work well for the monstera especially if you don’t get lots of natural sunshine into your home. Or you can use it to supplement light in the winter.
But grow lights will emit heat.
So, you want to keep the plant a safe distance from the bulbs.
Otherwise, the intensity of the bulbs along with the long hours of exposure can cause sunburn in monstera leaves.
In this case, it is the proximity of the grow lights to the leaves that causes this. But the long hours (12-16 hours a day) that will cause most of the damage in the long term.
So, ideally keep the plant at least 8 to 12 inches from the bulbs to avoid this.
Prune the Damage Leaves
Once the leaves of your monstera get sunburned, there is no recovering.
It is not like your skin that will regenerate after getting too much sun in the beach.
With plants, the damage is permanent.
This is why you want to avoid monstera sunburn especially if your plant already has huge, fenestrated leaves. It would be such a waste.
If the damage is small or only affecting some sections, you can reshape the leaves by just trimming off just the damaged sections.
Of course, how the leaves will ultimately look will depend on where the burn marks are and how big they are.
So, you may end up with some awkward or weird shaped leaves after.
The other option is to just cut off the damaged leaves altogether. This will allow new leaves will grow. But it will take patience for them to get big.
Add Water if it is Dehydrated
If the monstera sunburn is caused by dehydration then you’ll need to figure out what the cause was.
In many cases, it could just be lack of water.
However, it the dehydration was accelerated by too much light or very hot temperature in that location, then it is a good idea to fix the other issues as well.
As for a dehydrated monstera, it is important to avoid this as much as possible.
The longer the soil stays bone dry, the higher the risk that the roots dry out. When the latter happens, it could cause the plant to eventually die.
In some cases, the roots will get very brittle and break.
This means you lose those roots which will affect how much moisture and nutrients the plant will later be able to absorb from the soil.
The best way to rehydrate your monstera is to use bottom watering.
Depending on how big your monstera is, you can use a sink, bathtub, large container or something else.
Just place the plant in a receptacle and fill that with a 3 or so inches of water.
The holes at the bottom of the pot will let the plant’s soil absorb the water at its own rate.
And the goal is to all the soil to get saturated. You’ll know when this happens by feeling the surface of the soil.
Once its gets moist, you can take the plant out of the sink, bathtub or container.
Then let it completely drain afterwards.
This takes a while as the water is absorbed at the soil’s own pace.
So, a small plant can take 10-15 minutes, while a larger plant can take 30 minutes to 1 hour. Just come back to check the soil.
Once the top 2 or so inches feel moist, you’re done.
Make sure to let the soil completely drain after to avoid overwatering.
Again, this can take anywhere from 10 to 30 or so minutes.