Your Monstera deliciosa or Swiss cheese plant’s delightfully split leaves have taken on a new attribute lately, which is curling. Some of the Monstera’s leaves are curling down while other leaves have parts that are curling upward. I’ll tell you exactly why the Swiss cheese plant’s leaves curl and what you can do about it.
Why are my Monstera’s leaves curling? The Monstera’s leaves often curl for two main reasons: the plant’s conditions are too dry, or the Swiss cheese plant needs more hydration. Additionally, rootbound conditions, heat stress, pest infestations, transplant shock, and overwatering are other causes.
Ahead, I’ll talk further about what causes a Monstera’s leaves to curl, including downward and upward curling causes. I’ll also discuss how to treat the curling leaves on your monstera, so keep reading!
Why Are My Monstera Leaves Curling? + How to Fix It
The Monstera deliciosa or Swiss cheese plant is considered an easy indoor plant to grow. Easy though doesn’t always mean effortless, as you may have realized since your monstera plant’s leaves have begun to curl.
Sometimes, this curling can be upward, and you might even notice the Monstera leaves curling downward.
Per the intro, let’s look further at why your Monstera plant’s leaves are curling in any direction.
Lack of Humidity
The split-leaf philodendron or Monstera needs higher humidity than average, at least 60 percent and up to 80 percent.
Your home or office likely only has a relative humidity between 30 and 50 percent. Clearly you’ll need to add some humidity to create an atmosphere where your monstera can thrive.
You can see then very easily how you’re creating a humidity deficit for the Swiss cheese plant, even though it’s completely unintentional.
The reason the Monstera needs humidity is to replicate its tropical conditions, as this plant originates in southern Mexico’s forests.
Allow me to explain why plant leaves curl and you’ll better understand why your Monstera deliciosa is behaving this way.
When a plant’s leaves curl, the plant is struggling for moisture. In an effort to retain what moisture is left on the surface of the leaf, the leaf curls up and usually won’t open again until conditions have improved.
So how do you know what the humidity levels are in your office or at home? You’ll need a hygrometer for that, which is a handy gardening tool that reads moisture.
Here’s a link to the hygrometer I use.
What if it turns out that the humidity levels for the Swiss cheese plant are too low indoors?
Skip misting your plant and buy a humidifier instead. Misting would take up far too much of your time and can possibly cause additional mold issues down the road.
Don’t get me wrong, the occasional misting of certain indoor plants can help in the short term. but when you’re dealing with the leaves on your monstera curling, misting is not an acceptable solution.
Using a spray bottle to mist leaves that are curling from lack of humidity is like opening your refrigerator to cool your house off. It’s too small and it’s just the wrong tool for the job.
This is a job for a humidifier.
Humidifiers are small, low-cost with a high return on your investment making them highly beneficial to your indoor garden for the long term.
For those growing a Monstera indoors, who have the bathroom space and enough light, you can also consider moving your monstera plant into your bathroom.
Each time you take a shower, or your roommate or family member does, the split-leaf philodendron gets a huge blast of moisture!
If a lack of moisture makes the Monstera’s leaves curl, then a lack of water will definitely do it.
Watering the Swiss cheese plant is one of the more difficult elements of its care. The plant needs consistently moist soil, but the soil has to be only slightly moist.
You should only allow the soil to dry out four inches max before you replenish the Swiss cheese plant’s water supply.
Should its conditions continue to get drier from there, then your plant is officially being underwatered.
If you’ve noticed that the Monstera leaves are curling and turning brown or yellow as well, underwatering is likely the reason.
Underwatering causes dehydration in plants like the Monstera deliciosa. The leaf tips and edges will die first, turning brown and feeling very dry and crispy.
The Monstera’s usually tall, proud leaves will begin to sag and fall flat too. All growth will stop.
Plus, you’ll see the telltale leaf curling in your split-leaf philodendron. The plant is desperate to retain whatever water it can, so the leaves curl up.
To fix an underwatered plant, water your Monstera more to maintain slightly moist conditions.
Prune the dead parts of the leaves, as they’re not coming back. You don’t have to cut off the entire leaf though, only the brown or black parts. Disinfect your shears when you finish.
The Monstera deliciosa can reach sizes of 10 to 15 feet long, 4 to 6 feet tall, and up to eight feet wide indoors. It’s no small plant by any means, and will likely need to be repotted multiple times throughout its life.
The only way a healthy Monstera plant can remain in the same pot would be because you pruned it annually or biannually.
Admittedly, it can take many years for the Monstera plant to reach its full size. About two to three feet of growth can occur every year if you’re lucky. Without proper light, growth will slow and you may only see about one foot of growth in any direction.
Thus, about every two or three years, it’s time to repot the Swiss cheese plant. If you aren’t already doing so, then that can explain why your plant has curled leaves.
More than likely, your Monstera is rootbound. If you’re new to indoorplantsforbeginners.com or indoor plants in general, allow me to explain what rootbound means.
A plant’s roots grow deep in the soil. When you regularly upgrade your plant’s pot, the roots have a place to stretch out and expand appropriately.
Without upsizing the pot, the roots are stuck. They will begin to circle the interior of the container and then latch onto the sides. Roots from rootbound plants often emerge from the pot’s drainage holes too.
Even if that doesn’t happen, the Monstera’s root system is still under duress.
The root system is trying to provide nutrients to the new leaves, but it can’t do it. This causes any new growth in your Monstera to have an unnatural shape. The leaves will also curl.
How do you fix a rootbound plant?
In short, safely remove the plant and repot it in a container that’s between 5 and 10% larger than the container it was in previously. Avoid repotting it in a pot or container that’s much larger than it’s existing container
SIDE NOTE: Repotting a plant in a container that’s too large for it to avoid having to repot it again in a year or so is a sure way to sentence your plant to death by root rot.
You’re going to have to take it out of its pot. For an indoor plant the size of a mature or fully grown Monstera, this is a lot easier said than done.
Depending on the size of the monstera you may need another person, maybe even a second person to help you. One person should hold onto the base of the Monstera while the other person grabs the pot.
If the Swiss cheese plant won’t budge, then take a knife and encircle the base of the pot with it, shoving the knife down as far as it will go (but gently!).
This is sort of like when you cut around the perimeter of a cake to get it out of the pan. You’re trying to dislodge the Monstera roots from the side of the pot so you can take the plant out.
Once your split-leaf philodendron is finally free, prune back that overstressed root system. Be sure to clean your pruning tools when you’re finished to prevent passing on any fungus or plant diseases you may have come in contact with..
Now it’s time for a new pot for the Monstera deliciosa. Measure the current pot diameter and then buy a pot with a diameter that’s two to four inches greater than the original size.
Fill the new pot with soil, put your Monstera plant in the pot, and add some water so conditions aren’t too dry. The new Monstera leaves should soon stop curling.
Some new indoor gardeners might assume that because the Swiss cheese plants needs lots of humidity that it must like very hot temperatures as well.
That simply isn’t true. The Monstera appreciates only some warmth, preferring temperatures between 60 and 80 degrees Fahrenheit.
Once the temps exceed 80, your split-leaf philodendron is in trouble.
All indoor plants are susceptible to heat stress, which is induced when the plant is exposed to temperatures outside of its comfort range.
Sometimes, it only takes temps a few degrees higher than that comfort range for heat stress to kick in.
In the case of the Monstera deliciosa, it can handle temperatures no higher than 85 degrees. In hotter conditions still, it will begin to show signs of heat stress.
The Monstera plant’s leaf edges will dry out as they did when you underwatered the plant. Your Swiss cheese plant will also wilt and sag.
The leaves can roll or cup to hold close whatever moisture is left.
In severe cases, the Monstera plant can look sun-scalded like it received too much sunlight.
What can do you do for an indoor plant that’s suffering from heat stress? First and foremost, get the split-leaf philodendron out of the heat immediately.
Bring the plant to cooler conditions than usual, at least for a few hours. Deeply water your Monstera plant, as it likely lost all the hydration in its pot.
The next day, once your plant has had some time to recover from the shock, you can prune away the dead leaf bits.
The Monstera deliciosa is prone to a variety of pests, including scale insects, whiteflies, aphids, and spider mites.
Although these insect species couldn’t be more disparate, they all have one goal in mind. They want to suck your Monstera plant dry.
How do you know your poor plant has a pest infestation? Well, in many cases, the insects leave a residue behind or might be visibly noticeable.
Scale insects, which are flat and very tiny, are hard to miss when they congregate together.
Mealybugs secrete a sticky residue known as honeydew, usually on the underside of the leaves where they live and feed.
The honeydew can eventually lead to the development of sooty mold, which is black.
Spider mites spin white, silken webs that, if spread across the surface of a Monstera plant’s leaves, should be easy enough to see.
If you somehow miss a plant infestation on your Swiss cheese plant, your plant will tell you that something is wrong in other ways.
It could drop leaves even when it’s never done that before. The branches, stems, and leaves may develop abnormal yellow spots.
Entire leaves can turn yellow as well, and the yellow leaves will curl.
The first step when treating a pest infestation in the split-leaf philodendron is identifying which insect has invaded your plant. I recommend using the above information to help you do that.
Whether it’s aphids, whiteflies, or the other insects I’ve talked about in this section, you can kill them all using water and rubbing alcohol.
If you don’t have rubbing alcohol available, you can use liquid dish soap in its place. You need a gallon of water and then a tablespoon of dish soap.
In the case of aphids, if you’re feeling brazen enough, you can manually remove them from your Monstera plant using chopsticks or another long instrument.
Are your Monstera leaves curling after repotting? Then it’s likely a case of transplant shock.
I talked earlier about upgrading your Swiss cheese plant’s pot, which you’ll have to do every couple of years. Moving your plant is a natural part of life, but that doesn’t mean your plant has to like it.
The Monstera deliciosa, like all other indoor plants, can fall victim to transplant shock.
The symptoms that appear are like those caused by heat stress, but this time, it’s because you moved your plant.
Your Monstera plant may develop leaf scorching, which causes the leaves to become golden or bronze, especially around the leaf margins and veins. Then that tarnished tissue turns dry and crispy.
The other symptoms include leaf shedding or wilting and leaf curling.
Although moving your plant is inevitable, you should only do it when it’s absolutely necessary.
If your Monstera is suffering from transplant shock, you can also help it.
Now is it not the time to get lax in your care routine for the Swiss cheese plant. Maintain slightly moist soil and set temperatures no higher than 80 degrees.
After watering your struggling monstera with sugar water many indoor plants bounce right back while others, it has no effect. It’s worth attempting though.
Many indoor plants survive transplant shock, but it can take days to years for the plant to make a full recovery.
The last cause of Monstera leaves curling is overwatering.
This may seem strange to you. All along, your Swiss cheese plant has curled its leaves to retain water. If the plant is being overwatered, why would it need to cup its leaves like that?
Well, it’s sort of like a defense mechanism. The split-leaf philodendron is trying very hard to shield itself from stress, which in this case is caused by overwatering.
You may notice that the Monstera plant’s leaves curl upward.
Overwatering can be dangerous for your plant, as it can lead to a fungal disease known as root rot.
Root rot kills your Monstera deliciosa’s healthy roots until the plant cannot sustain itself and dies.
If you’ve been guilty of overwatering your Monstera plant a time or two before, allow the water to exit the drainage holes. Wait a little longer to water the plant again.
Root rot shouldn’t be an issue if you’ve overwatered seldomly.
What if root rot has already taken hold? You’ll have to remove your Swiss cheese plant from its pot and prune the dead roots.
Buy a new pot and fill it with fresh, dry soil. After pruning (and disinfecting your shears), place the Monstera plant in the pot and water it only a little bit.
If your split-leaf philodendron’s root system is stable enough with the dead roots removed, then the plant will live.