Why Do Calathea Leaves Close At Night? (With Possible Problems)

Calatheas have a very active lifestyle accompanied by their beautiful patterns. They tend to move their leaf position during the day and close up during the night. This is the reason they are also called prayer-plants. 

But why do calathea leaves close at night? Can there be possible problems? Let’s find out.

In general, most varieties of calathea move their leaf joints following the light, so they close their leaves at night. However, if a calathea is not folding up at night, it indicates something is wrong, such as lighting issues, watering problems, inappropriate humidity, or temperature.

This guide will discuss when, how, and why a calathea moves during the day and closes up at night. We will also explain the reasons behind a calathea not folding up during the night.

Do all Calatheas close at night?

Calatheas are available in many varieties. But whichever Calathea variety you choose for growing indoors, all of them will close up at night. 

That is the reason they are known as prayer plants. It seems like they fold up their leaves for praying. 

Calathea and the plants belonging to the family Marantaceae (arrowroot family) fold up their leaves at night. Both of them fall under the prayer plant family.

Not only do calathea close, but they also move their leaves throughout the day. 

If you own a bunch of Calathea varieties, all their leaves will move in different patterns and positions. It is natural and looks unique. 

Some varieties will move their leaves more dramatically than the other varieties.

So, you must not worry about the different movements in your Calathea leaves or the closing up of their leaves at night. Nothing is wrong with your plant. 

When the Calathea doesn’t move or close at night, then that is instead a problem.

When do Calatheas move and fold up?

Time Lapse Calathea's moving their leaves.

Calathea plant leaves keep moving throughout the day to adjust themselves in positions. They are constantly moving upwards or downwards, according to the movements of the light they receive.

One drastic change in their movement appears when the evening arrives.

After sunset, when it gets dark, the Calathea leaves fold up in a vertical position. 

From being bushy spread-out leaves, the leaves suddenly turn into long feather-like shapes. Sometimes, when they fold up, they reveal beautiful rose-like colors under the leaves hidden during the daytime.

This movement in the Calathea plant is known as nyctinasty. Even the Maranta leuconeura plants fold up their leaves. Both these plants are known as prayer plants because they go through this nyctinastic behavior.

The timing of Calathea leaves movement depends upon the movement of sunlight. 

When the sun rises, the leaves start their movements, and the moment the sunsets and sunlight disappears, the leaves start folding up. It is a dramatic and unique feature found in all Prayer plants. 

Calathea generally opens up in the morning 20-30 minutes after the morning sunlight hits them. They will start folding up gradually when the light starts fading from the afternoon.

How does Calathea move and close up?

Calathea is supposed to have a unique organ known as the pulvinus. It is a tube with thin-walled cells through which water can be quickly be taken up or released. It enables the leaves to swell and shrink dramatically.

These organs are to be found in the Calathea leaf base. You cannot spot them easily, though. 

When this pulvinus organ holds a good amount of water, you can identify the organ while seeing the thickening of stems under the leaves.

This Nyctinasty behavior differs for some plants that change and adjust their positions by facing the sun. This movement is known as Phototropism. 

It happens when the growth rate of the cells is quite different on the opposite side of the plants. The shady portion of the stem will grow faster and curve towards sunlight.

Calathea’s movement depends more upon the light’s intensity than direction. 

The organ present in Calathea stems does not tilt much towards the sun as Calatheas do not enjoy the direct sun. It moves based on the light’s intensity.

Why does Calathea move and close up?

The reason behind Calathea spreading out during the day and closing up during the night is debatable and quite the subject of argument and discussion. 

Some convincing theories behind this movement can be:

• Proper regulation of temperature: When the leaves close at night, the plant’s exposed regions close, which helps the plant lose heat during cold nights.
• Controls moisture: The closing up of the leaves vertically during the night promotes dripping water drops and water vapor downwards towards the roots. It allows the plant to receive a little more water. This further decreases the risk of fungus infestation due to wet leaves.
• Protection from insects: When the leaves are wide open, the insects can have a lot of places to hide. But the closing of the leaves at night reduces their chances of hiding.

Though the reason behind Calathea’s nyctinasty behavior has always been a puzzle, these reasons are accepted as quite convincing logic to some extent.

Why is my Calathea not closing up at night?

Calathea closing up at night is a common occurrence. Instead, when a Calathea doesn’t close at night, it is a sign of distress. 

The whole plant will stop its dramatic movement during the night and the daytime. In this point, I will discuss some common reasons behind Calathea not closing at night and how to fix the problem.

Lighting issues

Just as the sun comes up and goes down every day, humans rise in the morning and sleep at night, Calathea behaves the same way. 

When the first sunlight touches them, they spread out, and when the sun goes down, they close up their leaves. It is their natural cycle.

But, when the plant doesn’t close up, it means they are not getting enough darkness to close up. This happens when the Calathea gets too much light, even after dark. 

The first thing to do is give your Calathea the required darkness.

Solution:

• Ensure that your Calathea receives ample indirect sunlight throughout the day and the required darkness at night. It will fix the problem of Calathea leaves not closing.
• If your Calathea plant’s position doesn’t get such ideal light conditions, you can try changing its position to receive both indirect light and darkness equally side by side.
• You can place your plant near an east-facing window. It will give the perfect light and darkness.
• As these are tropical plants, never expose them to direct sunlight. That might result in sunburns.

Overwatering

It is not only excessive light that results in not closing of Calathea leaves but also inadequate watering. It is a mistake done by more or less all houseplant growers. But with little practice, anyone can master this.

Calatheas enjoy growing in moist soil but not damp or soggy soil. A waterlogged Calathea will not allow the leaves to close at night.

Moreover, in the worst conditions, your calathea might face root rot, which is another nightmare.

Due to such unhealthy situations, the roots will suffocate due to excess water, and the calathea will fail to intake water or release it through their pulvinus organ. 

As a result, the nyctinasty behavior won’t occur, and thus the plant will not close up.

Solution:

To solve this issue, you should stop watering for a while. Try taking some preventive measures to stop overwatering:

• Ensure that your potting mix supports sound drainage.
• The pot you use for your Calathea should have working drainage holes to drain the excess water.
• Water your Calathea plant only when the top 2 inches of soil dries up. Keep checking the soil’s moisture by using a moisture meter or poking your finger into the soil.
• Place your calathea in a place with a good amount of airflow and bright indirect sunlight. Both of these will help in drying out the soil quicker.
• Observe your Calathea daily to watch for any signs of overwatering like yellow leaves, brown tips, edges in the leaves, droopy leaves, etc.
• Whenever you find such signs, check the roots immediately. Get rid of all the mushy, soft, and dark brown roots. 
• Repot with new pot and fresh soil if the condition is worse.
• If all goes well, your calathea will be healthy within 1-2 weeks.

Underwatering

Another common reason behind Calathea leaves not closing is the lack of water. 

If your calathea doesn’t get enough water, water intake and release won’t occur through the plant’s pulvinus organ. Thus there won’t be any natural movement of the plant without water.

Moreover, a dry plant will always hamper the plant’s health, for which the plant won’t function properly, including the closing of leaves.

Solution:

Treating an underwatered plant is relatively easy than overwatering because immediate adequate watering can solve the issue. But the plant will take time to come back to its normal health and behavior.

To prevent underwatering:

• Water your plant immediately when the top 2 inches dry up. Regularly check the moisture level, and don’t keep your plant soil dry for too long.
• As Calathea are tropical plants, try to provide high humidity. It would keep them hydrated to some extent.
• If you are a bit ignorant about following a correct watering routine, you can try using self-watering pots for your plant. You just need to refill the reservoir once a month, and the pot will perform all the correct watering for your plant.

Also read: Overwatering Vs Underwatering Plants: Signs, Fix & More

Low humidity

As Calathea belongs to the tropical regions, they will need a high amount of humidity to thrive, around 60%. They are more habituated to humid and moist conditions.

Now while they grow in their natural habitat, they get everything adequately from Mother Nature. But, indoors, you will have to provide the correct quantity of humidity, at least 50%.

Indoors, the humidity is relatively less than outdoors, and they will grow less rapidly. Low humidity will be responsible for Calathea plants not closing up at night.

Solution:

Increasing the humidity if your Calathea is not getting enough is an excellent way of helping your Calathea close up at night.

• If you have many tropical plants along with Calathea, installing a humidifier in your room will provide the humidity they need to thrive.
• If you don’t have a humidifier, use pebble trays to increase the humidity for your Calathea plant.
• Keep all moisture-loving houseplants together in one place. It will help the plants to create their ideal humid environment with their transpiration.
• You can place your Calathea in locations with high humidity, like the bathroom or kitchen (away from ovens).

Low and fluctuating temperatures

Being tropical plants, Calatheas need warm weather conditions for survival. Thus, they should not be exposed to low temperatures or cold drafts. 

The ideal temperature for Calatheas ranges between 65°F-80°F. It usually is available in all houses. 

As most houses have air conditioners, you should be careful while positioning your plant. 

The cold drafts from the air conditioners can be very harmful to your Calathea plant. It will affect their health, hampering the plant’s normal functioning, including not closing up the leaves during the night.

Solution:

• Keep your plant away from air conditioners. You can keep both AC and your Calathea in the same room, provided your plant is away from the AC, and the temperature of your AC should be within limits.
• Avoid keeping your Calathea under the direct air of fans.
• If your plant is kept near an open window, remove it from there if it is cold and windy outside.
• Your Calathea will need special care during the winters, such as less watering, no fertilizing, maintaining proper humidity, keeping them near bright areas, etc.

Pest infestation

Another critical cause behind the no closing up of the Calathea leaves is pest attack in the plants. 

Pests such as spider mites or aphids are found in more or less all the indoor plants, including Calathea.

The mites create a web-like structure on the leaves, harm the tissues of the leaves, resulting in zero movements of the leaves. 

You will find fine web lines on the leaf edges and surfaces. The spider mites will look like tiny dots all over the leaf surface.

Aphids suck out all the saps from the leaves, leaving the plant lifeless and its leaves distorted. It will harm the plant’s health. 

Without proper health, the plant will not perform well, which means neither will it close at night nor make any movements during the day.

Controlling pests:

• You can handpick them if their colonies are large and visible. Wear gloves before dealing.
• You can give your Calathea a good shower and place it under a bright area for some time.
• Soak a cotton ball in rubbing alcohol to wipe out the pests.
• Spray neem oil. This spray is very effective for treating and preventing pests. Spray some and let the solution remain on the leaves. Use this until all the pests are gone.
• You can use any other readymade organic insecticides like liquid dish wash spray or herbal sprays.
• If an organic method doesn’t work, use chemical ones. But be careful before applying.
• After trying these ways, provide your plant with its requirements adequately.

Final thoughts

Calathea closing up at night is a prevalent and expected behavior in this particular plant. However, Calathea not closing up is a problem, but nothing serious. With the correct steps, you can fix this issue.

Calatheas, not closing indicates that something is wrong in the plant, and you need to find out the problems and fix them quickly. Try every possible fixation needed to find out the exact reason behind Calathea not closing.

The reasons explained behind Calathea not closing also have other signs. So you need to know them and then declare the actual reason and fix it. 

For example, if your Calathea receives low humidity, along with Calathea not closing, there will be other signs, too, like browning at the tips and edges of the leaves. So inspect well and then take action.

Mostly improper lighting is responsible for the no closing up of Calathea during the night. Take good care of your plant’s lighting conditions, and you will again see those dramatic and unique movements in your Calathea.

Source: NCBI, University of Florida, Wikipedia,  Growing Indoor Plants with Success, Agriculture, and Natural Resources, University of California, Missouri Botanical Garden.