Calathea Leaves Curling | Causes and Solutions

Calathea plants, Calathea sp., commonly referred to as rattlesnake plant, prayer plant, and zebra plant, make wonderful additions to any household for their striking striped foliage, quick-growing nature, and if given the proper growing conditions, their almost maintenance-free existence. 

Unfortunately, these popular houseplants don’t tolerate inconsistencies, which lead to problems with leaf curling, yellowing, and browning. So, if you encounter Calathea leaves curling, then you’ll benefit from reading this article to determine how to fix it before it is too late!  

Reasons for Calathea Leaves Curling

Environmental factors, especially those associated with soil moisture, climate, and nutrient availability, will cause leaf curling in Calathea plants. Leaf curling is often the first sign of trouble and can quickly lead to chlorosis or yellowing of the leaves, which is followed by leaf browning and plant death. 

Leaf Curl Symptoms and How To Fix

Inadequate soil moisture levels, temperature stress, low humidity, and nutrient deficiencies are among the top causes of curling leaves on Calathea plants. Here are all the symptoms you should look out for, the likely causes, and exactly what you need to do to fix them.

Downward Curling & Wilting: 

Overwatering causes root rot issues that lead to downward leaf curling and wilting. This is then quickly followed by leaf chlorosis which causes the leaves to appear pale and soggy. 

If the soil remains saturated for a prolonged period, then the roots will suffocate and the Calathea will likely not recover. 

How to Fix

If your calathea’s soil is not drying out between waterings, then switch to a soil mixture that will provide better drainage while still having enough water retention for optimal growth.  

The following soil mixture works great for tropical plants including Calathea:

  • 50% Organic Potting Soil 
  • 20% Orchid Bark 
  • 20% Perlite
  • 10% Worm Castings

Upward Curling & Wilting: 

Underwatering causes leaf curling, often in the upwards direction, and is the plant’s attempt to prevent any further water loss from transpiring leaves. 

Leaf curling is followed by wilting and leaf chlorosis and if severe enough, browned leaf edges will appear and spread as the plant dies. 

How to Fix

Slowly water your thirsty Calathea by giving it a cup of water every few hours for 1 – 2 days. This method prevents plant shock from over-saturated soil and reduces the leaching of precious nutrients. 

Thereafter, water only when the top 2 inches of the soil feels dry, which should be about once per week in the growing season. 

Sudden Curling of Green Leaves:

Temperature fluctuations that reach below 55 or above 80 degrees Fahrenheit will cause Calathea leaves to suddenly curl. During the beginning stages, leaves often remain green but will begin to yellow and brown if improper temperature conditions continue. 

How to Fix

Relocate your Calathea away from main doors, sources of blowing air, and out of direct sunlight. Keep the temperatures in the room between 65 – 80 degrees Fahrenheit and water thoroughly after any damage has occurred. 

Curling and Browning Leaf Tips:

Low relative humidity levels will cause curling and browning of leaf tips on most tropical plant species. The browning is often accompanied by leaf chlorosis near the damaged tissue. 

How to Fix

Keep the humidity above 50% by using a humidifier or by adding a bed of moistened gravel to the catch tray of your plant.

Curling and Browning Leaf Edges: 

The use of unfiltered tap water can cause salt, mineral, and chemical build-up in the soil of your Calathea plant, which can lead to the browning and curling of leaf edges. If not rectified, wilting and chlorosis from nutrient deficiencies will quickly ensue.

How to Fix

Flush your calathea’s soil with fresh, filtered, or rainwater. Use enough water to fill the volume of the container the plant is in. Repeat 2 – 3 times over the next week. 

If your Calathea doesn’t recover after a week of flushing, then the build-up is too severe, and transplanting your plant into fresh soil will be necessary to help prevent the roots from absorbing any more chemicals.  

Lower Leaves Curl and Drop: 

Calathea plants naturally shed their lowest leaves as they grow. As the leaves die, they will start to curl, turn yellow, and eventually fall off. 

How to Fix

This is a natural process, so if the rest of your plant is green and healthy, then there is nothing that needs to be done! But removing these spent leaves will reduce the chances of pest infestation. 

Leaves Twisting: 

Herbicide injury is a common cause of twisting, curling, and deformed leaves, especially on new growth. This can be caused by outdoor herbicide drift, misuse of common products, or using contaminated soil, compost, or mulch. 

How to Fix

Rinse the entire plant thoroughly of any residue, which will dilute the herbicide and minimize its damaging effects but must be done promptly for it to work. 

If the herbicide is soil-active, then incorporate activated charcoal at least 6 inches into the soil so that it will absorb the herbicide and render it inactive. Apply at a rate of ¼ lb per 12.5 square foot. 

Curling and Yellowing Leaves: 

Potassium deficiencies can cause curling along the edges, as well as Calathea leaves to turn yellow (also known as leaf chlorosis). If the deficiency is severe, then dark purplish scorched spots will appear along the leaf’s margins. 

How to Fix

Mix 1 teaspoon of all-purpose fertilizer into 1 gallon of water. Use an NPK ratio of 15-15-15 to limit the burning of sensitive roots and prevent nitrogen deficiencies, which are also common in Calatheas. 

Then, replace a watering with this solution at least once per month during the growing season. Limit any fertilization during dormancy to prevent salt build-up in the soil. 

Curling leaves with Yellowing Leaves and Dark Spots: 

Bacterial Leaf Spot Disease will cause leaf curling that is accompanied by black lesions with yellow halos. The beginning symptoms of this disease include water-soaked spots on young leaves and sticky secretions from forming lesions. 

How to Fix

Foliar applications of copper bactericides can aid in disease prevention or early-stage treatment but are ineffective for large-scale or severe infestations. Disposal of infected plants is the best option. 

Since treatment of bacterial leaf spot disease in Calathea plants is so difficult, switching to drip irrigation or watering without wetting the leaves and isolating any newcomers are the best means of preventing initial infection or spreading.