9 Reasons The Leaves on Your Calathea Plant are Curling

Calatheas are grown for many reasons, but the top of the list has to be their stunning foliage. Their leaves are often described as painted, featuring careful brushstrokes, intricate patterns and a contrasting underside of maroon or burgundy.

These interesting leaves have given the plants many common names including peacock plant, cathedral window plant, rattlesnake plant, zebra plant or prayer plant (to name a few).

With the right care, Calatheas can thrive in an indoor setting with ease. However, as with any houseplants, there are times when they need extra help – particularly when their lush, large leaves begin to curl.

This common issue has many causes. Take a look at your plant and assess your care routine to see which of these 9 potential reasons for curling leaves are most likely.

Lack of Water

Calatheas will curl their leaves to let you know that they are unhappy. One of the most common reasons for this unhappiness is lack of water.

Underwatered Calatheas will typically curl their leaves inwards rather than outwards in an attempt to conserve moisture. These plants prefer soil that is consistently moist, allowed to dry out only slightly before watering again. Water any less than this and you may notice a curling pattern emerging.

It’s best to water your Calatheas regularly from the bottom drainage holes. Place water in a sink or bucket and allow the potted plant to soak up moisture from the bottom for around half an hour.

You may need to top up from the top to make sure the soil is saturated and to flush the soil every few waterings. But, be careful not to splash the leaves of the plant when watering. This encourages leaf spot, especially if the humidity is high.

Bad Water Quality

Some plants are affected by tap water that contains added minerals, chlorine, fluoride and salts. Calatheas are one of them.

Curling leaves may be a sign that your plants are unhappy with long-term tap water use. You may also find the tips browning due to salt build-up in the soil. Change to distilled or filtered water, or if possible, harvest rainwater for the best results. You can leave water out for a day or two to reduce some of the chlorine content before use.

If you have salt build-up in your soil, flush the soil thoroughly with warm water from the top of the container, allowing the excess to drain. You may need to do this a few times to completely rid the soil of excess salts.

Incorrect Temperature

The ideal temperature for Calatheas is between 60F and 85F. If the plant gets too cold, it will curl its leaves to protect them from damage. This also applies to areas with cold or dry drafts from open windows or air conditioners. Check the temperature in the area the plant is positioned to determine if this may be the cause of your problems.

If your Calatheas are growing on a balcony or patio, they should be moved indoors during excessively cold or hot weather. Extremes in temperature are detrimental to the health of your plants.

Lack of Humidity

The conditions in their native environments will tell you that Calatheas love high humidity. The humidity level in your home should be between 40 and 60%, but Calatheas will be happier with humidity levels closer to 60%.

You can increase the humidity levels around your plant by using a humidifier. For a slight increase in humidity, place your plants on trays of pebbles filled with water to give your plants a boost, especially in drier climates.

Overwatering

Too much water is equally bad for a Calathea and more than likely a result of bad drainage. Although they enjoy moist soil, it should not be waterlogged. Any excess water must drain out from the drainage holes without stagnating in trays or pot covers.

Any excess water, whether it be from lack of drainage or watering at the wrong time, is likely to cause root rot. This condition leads to stress that causes curling, yellowing and wilting.

The base of the plant may also turn black if the problem is severe. In this case, you will need to repot your plant, adding more drainage materials like perlite and coconut coir. Trim off the affected roots to avoid spreading the problem to the rest of the plant.

Excess Sunlight

The luscious leaves of a Calathea are quite sensitive to sunlight. They enjoy bright indirect sunlight and don’t handle direct sun very well.

Excess sunlight will cause curling for the plants to protect themselves from the harsh rays and to conserve moisture. It will also cause the leaves to fade and develop brown spots on the parts exposed to direct sun.

An easy fix is to move the plant into an area with less light. It shouldn’t be completely dark – simply moved away from the path of the direct sun to prevent damage. Cut off any burnt or damaged leaves and the plant should unfurl within a couple of days.

Overfertilization

Calatheas grow strongest when given a balanced fertilizer every couple of months during the growing season. But apply too much and you may notice leaf curl soon afterward.

Overfertilizing calatheas can cause the roots to become dehydrated and damaged. This transfers to the leaves which will become brittle, curl and dry out.

Try flushing the excess minerals out of the soil, rinsing until the water leaving the drainage holes run clear. Avoid fertilizing for several months to give the plant time to recover.

Pests and Diseases

Various pests and diseases may cause leaf curl. Tackling them immediately is key to saving your plant and preventing any further damage.

Small brown patches on the leaves may be a sign of leaf spot. This is usually caused by incorrect watering of the plants and not the soil. This can also be caused by the use of tap water. Remove the affected parts of the plant and water from the bottom in future.

Red Spider Mites are another pest that can cause leaf curl. These tiny pests are difficult to see and usually attack from the underside of the plant. It is wise to check all the undersides of the leaves of all your houseplants regularly to catch these pests before they become a real problem.

The first sign of spider mite infestation is webbing between the leaves and stems. The leaves may become mottled and curl with constant abuse. Improve air circulation and control using insecticidal soaps or horticultural oil.

Also look out for fungi like powdery mildew which forms white spots on the leaves and causes them to curl, botrytis in high humidity that causes grey mold, and southern blight that will kill off the plant quickly, causing root rot and lesions on the plant. In moist areas, you may also encounter rust, which forms visible rust-colored blisters.

Treat these issues with fungicides formulated for the control of these specific diseases and follow the instructions carefully. Isolate the plants from other houseplants and treat outdoors if possible.

Natural Movement

Calatheas will naturally move their leaves during the day and into the night. This is a tactic to preserve the plant’s energy. Some will move more than others and some will fold up at night to show the underside of their leaves, opening outwards during the day.

This may at first seem that the plant is unhappy and that the leaves are curling due to stress. But this is actually a natural phenomenon, and you should rather be concerned if your plant isn’t folding up at night. It’s particularly noticeable as calatheas get bigger, because these houseplants can have very large leaves.

Check for other signs of concern and if there are none, don’t worry about a little curling according to the times of the day.