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Why Are My Calathea Zebrina Leaves Curling? (And How to Fix It)

Indoor potted Calathea Zebrina Leaves Curling

With its large striking ovate leaves in different flashes of colors, Calathea zebrina is undeniable of the most popular and well-loved species under the Calathea genus. 

However, any plant parent who owns a Calathea zebrina will agree with me that these tropical beauties are also among the most challenging to take care of as they have very specific needs in terms of light, water, soil, and humidity.

If you are a Calathea zebrina plant owner like me, you may have already seen, at some point or another, the leaves of your precious foliage curling. 

Calathea zebrina leaves curling or curling inward due to lack of moisture, low temperature, lack of light, or overwatering. Underwatering is the most common cause of Calathea zebrina leaves curling. Insect infestation and diseases are also responsible for this problem.

In this article, I will share with you the most common reasons your Calathea zebrina leaves are curling and how you can treat each so you can successfully revive your adored plant!

Causes of Calathea Zebrina Leaves Curling

Underwatering 

Just like other Calathea plants, your Calathea zebrina prefers moist, yet well-drained soil.

As such, you need to ensure you are not letting its soil dry out. This is especially true during the growing season when the plant calls for more water. 

When you fail to give the plant enough water and the soil dries excessively, it will not get enough nutrients, resulting in dry, curling leaves.

Avoid this from happening as this may stress your plant and adversely affect its growth.

How to Fix

If you have not already done so, set a watering schedule and consistently follow it.

You can also use the “poke-a-finger” method to determine if it is already time to water your Calathea zebrina. To do this, follow these steps:

  • Poke a finger about two to three inches deep into the top layer of the soil. 
  • If the soil feels wet, your plant still has good moisture levels, so you can skip watering for the day. 
  • If it feels dry, on the other hand, it’s time you water your plant. 

While this diva-like plant doesn’t like to dry out, remember that it also doesn’t like to get wet all the time! So, be careful not to overwater, as too much water can lead to yellow, mushy leaves.

Overfeeding with Fertilizer

Similar to other houseplants, you need to add fertilizer for optimum growth of your Calathea zebrina. An excess of a fertilizer, however, can harm the plant and cause various issues. 

When you overfeed your Calathea zebrina, it will take up too much salt which will pull moisture away from its roots.

When this happens, the plant is in danger of chemical burns and dehydration, causing leaves to burn and curl. 

How to Fix

If you think you’ve overfed your Calathea zebrina, you need to act fast. Flush the soil of the plant by watering it, letting streams of water run through its pot’s drainage holes. 

Let the excess water drain completely and wait until the soil has properly dried out before watering your plant again. 

It is also important to remember to suspend fertilizing your Calathea zebrina during winter, as plants are not actively growing during this season.

Lack of Nutrition

Calathea zebrina leaves curling can also be an indication that your plant isn’t getting enough nutrients that it needs.

The deficiency of Phosphorus, a nutrient needed for the development of adenosine triphosphate (energy), sugars, and nucleic acids.

It makes Calathea zebrina, appear weak and inhibits leaf expansion, causing leaves to curl and be small. 

How to Fix

Fertilize your Calathea zebrina during the spring and summer using a balanced all-purpose fertilizer, such as 10/10/10 ratio on Nitrogen, Phosphorous, and Potassium. You can do this on a monthly basis.

To feed your plant properly, it’s also useful to have an understanding of the pH levels in potting mediums.

Your goal is to achieve pH levels between 5.0 to 6.0, as it is the ideal pH for Calatheas. You can adjust pH by adding liming materials, such as dolomite or calcium carbonate, to your potting medium. (Source: University of Florida, IFAS)

Temperature Stress

Being a tropical plant, Calathea zebrina thrives in warm and humid environments that mimic tropical jungles and rainforests.

Grow your Calathea zebrina indoors with temperatures ranging from 65- 75º F (18-24º C). 

Additionally, don’t place your Calathea zebrina in locations exposed to warm and cold drafts.

Heat stress due to warm drafts can cause rapid evaporation, making leaves curl up to retain moisture. Cold drafts, on the other hand, cause wilting and yellowing of leaves. 

How to Fix

Find a spot in your home with the ideal temperature for your Calathea zebrina.

If the leaves stay curled up, try adjusting your thermostat and watch your plant for a few days. Keep adjusting the temperature until you see the leaves start to unfurl. 

Root Rot from Overwatering 

If the leaves of your Calathea zebrina start to curl, you may want to check the plant for any sign of root rot, a condition caused by soggy soil as a result of overwatering. 

Water and other nutrients can’t make their way up to the plant when its root is rotting.

As a result, the leaves become dehydrated and desperately try to retain moisture, leading to curling and drying. 

How to Fix

  • Remove the foliage from the soil and check the roots; if the roots look black and mushy, they are most likely affected by root rot. 
  • Wash the roots carefully under running water to remove the affected parts. If a significant part of the root system has been affected and removed, prune back one-third up to one-half of the leaves. This way, the plant will have a higher chance to regrow its roots, as it will not have to support as many leaves. 
  • Repot the plant in a new, well-draining potting mix and place it in a spot ideal for its growth.

Water Quality 

Do you know that tap water contains salt, chlorine, fluoride, and other minerals that can be harmful to plants?

The salt build-up in the soil inhibits the roots’ ability to absorb necessary nutrients, causing the leaves of your Calathea zebrina to curl.

How to Fix

The best way to address this is to filter your tap water using a filtration system.

If you don’t have a filter, fill your watering container with water and leave it open overnight so the chemicals can dissipate. For best results, use distilled water or rainwater.

Too Much Direct Sunlight 

Calathea zebrina prefers bright or medium, indirect light. Too much direct sunlight, especially in the afternoon during the hottest time of the day. It will put a strain on the plant, causing its leaves to curl, as it tries to reduce its surface area exposed to the sun. 

How to Fix

If you’ve accidentally left your Calatheas soaking in the sun, move the plant immediately to a shady or partially shady location with a moderate amount of ambient light, such as a shaded garden or balcony. 

The most recommended spots are well-lit rooms that also filter direct sunlight, such as a conservatory or greenhouses.

Lack of Light

Plants, including your Calathea zebrina, need enough light to photosynthesize and produce energy in the form of glucose that is used to create roots, stems, leaves. 

If your plant doesn’t get enough light, it will curl its leaves and lean or stretch towards the source of light.

Insufficient light inhibits growth and may cause your plant to die due to its inability to produce food through photosynthesis. 

How to Fix

If you have kept your Calathea in a dark spot, such as a low-lit room or a bathroom with a small window, slowly acclimate the plant by gradually moving it to a brighter location.

You can also turn to artificial lights—from fluorescent, incandescent, LED, to horticultural grow lights—to grow your Calathea zebrina indoors, especially if the rooms in your house receive limited to no sunlight. 

Insect Infestation 

Curling leaves—along with speckled discoloration, browning, and drying—may also indicate that unwelcome visitors have infested your Calathea zebrina. 

Insect pests cause the leaves to curl when they suck the juices of young or new leaves that are still growing. 

Some of the most common culprits that infest house plants like Calathea zebrina are fungus gnats, mealybugs, aphids, spider mites, and scales. 

How to Fix

  • The first step is to isolate your Calathea zebrina plant from your other house plants until you have the pests completely controlled.
  • Check the infestations; if only a small and isolated part of the plant is infested, just remove and destroy the infected parts. If the roots of the plant are infested, on the other hand, take a cutting and start a new plant in a clean pot with sterile and well-draining potting soil. 
  • Dip a cotton swab in rubbing alcohol to wipe off aphids and mealybugs. You may need to use a fingernail to remove scales. For spider mites, you can spray the plant with water to remove the pests. 
  • If the pest infestation is in its early stages, spray the infested plant with insecticidal soap to eliminate the pests. 
  • If the infestation is severe, you may need to let the plant go so that it won’t infect other house plants. 

Diseases 

The high humidity that Calatheas zebrina requires in order to thrive also encourages fungal and bacterial diseases, which can manifest through curling leaves, wilting, and yellowing. 

One common disease among Calatheas is a soil-borne fungus called fusarium, which can develop when the plants are placed in a spot with low light and bad air movement. 

How to Fix

You can use a copper fungicide as a treatment for fusarium, but the best solution is to remove the plant from the soil, dispose of the soil, wash the roots, change the potting medium, and re-pot it to a new plant container. 

Low Humidity 

For Calathea zebrina plants, high humidity is a must! The plant absorbs moisture through its leaves; if the air is dry, the leaves will start to curl and turn brown. 

As such, it is important to up the humidity around the plant, especially during the winter months. 

How to Fix

While it is not a long-term solution, misting is the fastest way to address low humidity, as it can provide moisture for two to three hours.

When you are misting, make sure that the water you use is clean to avoid any bacterial or fungal overgrowth.

To achieve high humidity, you may want to use a humidity tray or an electronic humidifier to provide the necessary moisture.

You may also want to place your plant next to other tropical plants in your living space, as this can help promote humidity.

Calathea Zebrina Leaves Curling After Repotting 

Calathea zebrina does not tolerate frequent repotting, as the plant easily gets stressed. Only repot your Calathea zebrina once every two years, during the spring season, or when it is root-bound. 

If you’ve recently re-pot your Calathea and you notice that the leaves are curling, the plant may be exhibiting signs of repotting stress. Some common causes of repotting stress on plants, including Calathea zebrina, are the following:

  • Use of a different type of soil than the plant previously lived in.
  • Leaving roots exposed to air for a long time during the re-potting process
  • Placing the plant in a spot with a different lighting condition.

How to Fix

  • Make sure to use a similar type of fertile and well-draining soil. 
  • Check if the new container has sufficient draining holes. If it doesn’t have enough holes, you can drill holes to the new pot to allow excess water to drain. 
  • Place your plant in the exact same spot it originally inhabits so that it can get the same temperature and light it had before.
  • Provide enough water and feed the plant to promote growth. 

How to Prevent Calathea Zebrina Leaves From Curling 

Now that you know the most common reasons the leaves of your Calathea zebrina are curling, you are now better equipped at avoiding this from happening. 

The best way to prevent your Calathea Zebrina leaves from curling is to provide your plant with the right growing conditions to ensure that it grows healthy. 

Grow the plant in fertile, well-draining soil and follow a consistent watering schedule. Protect the foliage from direct sunlight, but give it enough light. 

Feed the plant the right amount of nutrients and always look for possible signs of diseases or insect infestation. 

Most importantly, make sure that you are providing the plant with an environment that is warm and humid, which is conducive to its optimum growth. 

Caring for Calathea zebrina can be a little tricky, as this tropical plant is finicky and requires special attention and care. 

With the right amount of information, however, you can successfully grow this lush foliage and turn your living space into a tropical paradise.