A healthy, well-nourished pothos plant will have broad and flat leaves. The entire leaf can stretch toward a light source when there is insufficient light, but when the edges of the leaves curl upward or downward, take it as a sign that something is off with the growing conditions.
There’s a plethora of reasons for pothos leaves curling, yet every single one is because the plant is stressed. Usually, the cause is dehydration resulting in plant stress for every houseplant, regardless of the species.
The tricky part with pothos plants is figuring out the underlying cause of stress.
Common Reasons for Pothos Leaves Curling
1 – New Leaves Curling Is Natural
When new leaves come through on a pothos, it is natural for the edges to curl slightly. As they mature, they unfurl.
The leaves will only curl in the beginning to retain enough moisture for sufficient growth. As it matures, the leaf unfurls, flattening out. Eventually, you should only be seeing small new leaves on a pothos with a slight curling on the edges, but all other mature leaves will be completely flat.
2 – Old Leaves Discolor and Curl
Similar to new leaves on pothos curling, when old leaves are on their way out, they can curl upward in a bid for survival by retaining as much water as possible.
When mature leaves are turning yellow or brown, and curling, they can be cut away to make room for new growth. A huge part in making a pothos plant fuller is pruning. The same applies about pruning for making pothos leaves bigger.
Remove old and fading leaves early and leave the brightest leaves to keep on growing bigger. Fading leaves will only deplete the plant of energy.
3 – Insufficient Water
Underwatering a pothos plant is the most common reason for the leaves to curl. It does it to preserve what little water it does have left. It is a natural trait of all houseplants. When plants become thirsty, leaves curl to preserve moisture. It is a sign of when to water it.
Before watering, check the top inch of the soil is dry to the touch. If the soil is moist, it does not need a drink. Dry soil and curling leaves are a sign to add water.
This is a plant trait that can be used as a guide to watering houseplants. Wait until the leaves curl, then top up with water. There is absolutely nothing wrong with that.
Moist soil and curling leaves indicate a different type of problem.
Staying with the watering issue, consider if it has too much moisture because overwatering is far worse.
It leads to rot and it’s usually caused by the pot being too big rather than plant parents being overly generous with watering.
4 – Adding Too Much Water
When too much water is retained in the soil, it damages the root system of plants. Overwatering will show the same signs as underwatering because technically, it is underwatered due to the fact that the roots are sitting in a compacted soil mix, lacking oxygen, causing damage to the roots to such an extent that they are unable to take up moisture from the soil to deliver nutrients to the rest of the plant.
The result from damaged roots is a plant with drooping and curling leaves because they lack the water to keep them nourished.
The overwatering issue is not always because indoor gardeners keep on topping up the pot with water. Decorative planters often have no drainage hole. Pothos need those.
When drainage holes aren’t present in the plant pot, water cannot drain efficiently. The technique to use with planters without holes for drainage in pots is to double pot your pothos.
What Is Double Potting?
Double potting is when you keep your plant in its nursery pot with the drainage hole and place it inside a decorative planter without one. The bottom of the decorative container needs to have at least 1” to 1.5” of gravel. The gravel absorbs the water that seeps through the drainage hole in the nursery pot.
An added advantage is the elevated humidity that comes from the water evaporating from the base gravel releasing excess moisture throughout the day. Double potting with a layer of gravel inside a decorative plant pot has the same effect as using a humidity tray.
If you want your pothos to flower, the higher humidity will be needed.
5 – Overheating
Soaring temperatures cause pothos to go into a defensive mode to retain moisture in the leaves. When it is too warm for the plant, the leaf tips curl upward. This is referred to as “cupping.”
The usual culprit that causes cupping on pothos plants is having it placed in direct sunlight, or a light source being too close to the plant, or a lack of airflow around the plant that will cause heat to continually accumulate throughout the day.
The ideal temperature range for a pothos is 70oF (21oC) to 90oF (32oC). When temperatures are outside of that range, in addition to the pothos leaves curling, it also causes the leaves on pothos to turn yellow or brown.
Browning leaves on pothos will usually be caused by exposure to direct sunlight. They need bright indirect light, otherwise leaf scorching is likely to occur.
Take into consideration that the ideal temperature for pothos refers to the temperature of the leaves and not the room temperature.
Appliances can alter the leaf temperatures of houseplants so do be aware of placing pothos too close to heaters, fireplaces, air conditioners, fans and similar appliances, as they are likely to alter the temperature around your plant.
6 – Inadequate Lighting
Leaves on pothos should be flat. No part of the leaf should be curling upward or downwards. When you are certain there is not a watering problem, drainage issues, and the temperatures are in the correct range, there is one last check to do pertaining to the growing climate, which is the lighting.
When the leaf is curling towards light, it points to a lack of light. When it curls away from light, it is too bright, or more likely, too warm because of the close proximity to the light source.
A common misconception with LED grow lights is that they do not produce heat. The bulbs themselves do not heat up excessively, but the housing units do!
When the leaves are curling away from a light source, it is likely overheating. Curling towards the light indicates that your pothos in needing more light. Without sufficient light, photosynthesis cannot happen.
Without photosynthesis happening, the plant struggles to produce the food it needs to stay in good health. That is the reason for pothos to stretch towards light, resulting in a leggy pothos plant.
7 – An Excess of Fertilizer
It is common knowledge that plants grow better with fertilizer. That is true, but it can easily be overdone. Repotting is a necessity for pothos every couple of years to prevent the roots from becoming pot-bound, which is when they encircle the pot.
At that point, the soil is likely too compacted for the roots to absorb moisture and oxygen in the soil. Instead, because it lacks oxygenation, roots rot, growth is stunted, and any new leaves that do appear are smaller than you’d expect.
When there is an excess of fertilizer accumulated in the soil, leaf discoloration shows because of fertilizer burn and it does need to be fixed.
Usually, excessive fertilizing on pothos results in a darker green foliage, sometimes yellowing, but at the leaf tips, the pothos leaves will curl downward and turn brown. If you see that, pay attention to the top soil.
When excessive amounts of minerals from fertilizers build up in the soil, the top layer can present with a white crust. This is an excess mineral build-up from feeding the plant too much fertilizer.
If you notice a crust forming on the top layer of soil, you have two options. Either stop adding fertilizer and only top up the water, or the safer and faster route to recovery is to repot your pothos in a fresh potting mix, then go easy on the fertilizer next time around.
If you do choose to repot early, do some root pruning before popping your pothos in a fresh potting mix. When too much fertilizer has been used, it is likely that some of the roots will be damaged. Perhaps not rotted, but some will be headed in that direction due to the inability to absorb the nutrients required.
8 – Mealybugs and Scale Insects
Scale bugs can be hard or soft. The ones that are more prone to latching onto the stems of pothos are the soft scale bugs.
These are small brown bugs that are oval shaped. They tend to congregate on the stem where most of the nutrients are traveling through the plant to reach the leaves. As a result, the scale bugs intercept the nutrients intended to reach the leaves.
The result of soft scale bugs on pothos plants is yellowing leaves that curl upwards. If the damage is extensive, you can simply cut away the damaged leaf to make room for a new one to grow in.
Alternatively, if the damage is miniscule (when caught early), you can pick these off and dab the leaves with rubbing alcohol.
Take Care with Rubbing Alcohol
Use a mix of 1-part 70% Isopropyl Alcohol (IPA) diluted with 9 parts of water on pothos plants. Without diluting it, the alcohol concentration can cause leaf burn.
This is because pothos plants absorb moisture through their leaves. They will also absorb anything you spray onto the leaves, which is why you should always dilute any pesticide, natural or not, and any spray-on fertilizer.
As a precaution, use one of the most damaged leaves as a test surface (it will likely need to be removed anyway). Spray the diluted rubbing alcohol solution on the leaf surface, leave for two days, then inspect for any discoloration.
If there is damage, further dilute the rubbing alcohol. If there is no sign of discoloration, spray the diluted mixture over the rest of the plant to treat for soft scale insects.
Without treating for scale insects, a secondary issue likely to surface is sooty mold. This sets in when the waxy coating of honeydew (insect excrement) coats the leaves, which blocks sunlight from reaching the leaves resulting in a lack of photosynthesis. The plant won’t thrive, but the fungal growth will.
When to Pay Attention to Scale Bugs?
In the summer when humidity is at its highest. Scale insects thrive in high humidity environments. They need the moisture and will starve your plant of it. The wetter the leaves on pothos plants, the more attractive they will be for scale bugs.
9 – Sap Sucking Plant Pests
Any insect that sucks the sap from the leaves of plants will cause pothos leaves to curl. They have the same effect as scale insects.
The only difference is that scale insects eat the plant, whereas sap sucking insects pierce holes in the leaves to suck the juices from them. The damage is the same because both result in the nutrients being hijacked by insects.
The most common plant pests for pothos grown indoors are the spider mite, fungus gnats, whiteflies, and aphids. In the vast majority of cases, these congregate on the underside of leaves making them difficult to spot. A few of any will do little damage.
Extensive damage happens as a result of colonies emerging due to any species of insect breeding. All are fast breeders so in addition to cleaning and sterilizing the foliage when insects are spotted on a pothos plant, the soil mix should be replaced to get rid of unhatched eggs.
10 – Root Rot
Roots rot when they are left sitting in standing water, or in the case of pothos, when the soil is soggy. As with overwatering and feeding a pothos too much fertilizer, the tips of the leaves curl downwards when root rot is in its early stages.
The longer the plant’s roots are malnourished due to excess moisture, fertilizer, or just sitting in compacted soil, the rot will get progressively worse. The sooner the plant is repotted the better.
When symptoms of root rot are present, inspect the root system and prune off any discolored roots. The reason for this is that compacted and moist soil is a breeding ground for bacteria and fungi disease.
Healthy roots on pothos plants are white. Any that are not should be cut off the root system before transplanting in a fresh potting medium.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.