Calathea plants are part of the Marantaceae family, a tropical flowering plant, but don’t expect it to flower indoors. Calatheas are grown indoors for their gorgeous patterned leaves.
It’s a spectacular ornamental plant, if you have the conditions for it. If the conditions fall out of favor, the leaves will throw a pity party, letting you know something’s off in the growing conditions.
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Why Leaves Curl on Calatheas?
Leaves curling on Calathea plants are a defense mechanism. They curl to shade from direct heat or preserve water. Both are a result of low humidity levels, dry soil, over-exposure to light, heat stress, or dry soil, which can also be the result of watering with hard water that lowers oxygenation in the soil.
5 Reasons for Leaves Curling on Calathea Plants and How to Fix them
Too Low a Humidity Level
Being a tropical plant, Calathea’s need at least 50% humidity. In their native habitat, humidity is around 90%. You’d need a greenhouse environment to achieve close to those levels.
Fortunately, you don’t need to go to the extremes. Calathea plants do well with humidity levels of 50% to 70%. The higher the better.
One way to tell if the moisture levels are too low is to inspect the tips. When the air is too dry for it, the leaves turn brown and feel crisp.
If left in dry air for too long, they can become so brittle that the tips of the leaves snap off.
If the leaves are feeling brittle, spray it with a fine mist from a decent distance so that the force of water doesn’t break the leaf. Misting the leaves will give it a few hours of increased humidity, but it’s not a long-term solution.
For longer term humidity increases, consider using a room humidifier, or if your plant is on the smaller side, a small desktop humidifier placed near it can increase humidity levels enough to save you misting it frequently.
For smaller humidifiers, direct the mist into the air above the plant. Not onto it. You want the plant to absorb its moisture through the air rather than applying water directly onto the leaves.
If you have more plants, you can take advantage of the transpiration rates by grouping multiple plants together, and for better results, use a tray lined with pebbles.
Water the pebbles and they’ll release moisture into the air throughout the day.
Insufficient Temperatures
The ideal temperature range for Calathea plants is between 62ºF and 81ºF (16ºC to 27 °C). Too cold and the leaves will curl to preserve heat. Too warm, they shrivel under heat stress.
Keep in mind that the temperature on your thermostat can’t give you an accurate temperature for your plant.
Place it beside a vent, or near an air conditioning unit, the stream of dry air being directed at it will damage the leaves. Sometimes to the extent of discoloration.
Dry Soil
Calathea plants prefer the soil to be constantly moist. If it completely dries out, the leaves will get dramatic.
Under intense drought conditions, the leaves brown, curl, go limp and droop. It is not a pretty sight!
Best practice for watering is to water it when the top inch to 2-inches is dry. For small plant pots, water when the top inch of soil is dry to the touch, and for larger plants, don’t let the top 2” of soil dry out.
You could use a hygrometer to monitor the soil moisture, but your finger is really all you need. If it feels dry, it’s thirsty.
Watering with Tap Water
Calathea’s, being a tropical plant, are used to the purest of water. Rainwater. Tap water is treated with multiple contaminants to plants.
Chlorine or chloramine (a combination of ammonia and chlorine), fluoride, sodium and other minerals are all added to tap water. It’s far too much for delicate plants.
Some additives, such as chlorine, can release through evaporation if you leave it for long enough, but there’s always going to be impurities.
Extended watering with tap water can cause minerals to accumulate in the soil. The more minerals there are, the more compact the soil becomes. The result… less oxygen leading to the roots becoming stressed.
The ideal water to use for Calathea plants is rainwater or distilled water.
Over Exposure to Light
Just like dehydration leads to leaves curling on Calathea plants, so too does too much light. Under direct sunlight, the leaves will react by curling. It is a defense mechanism.
The ideal light conditions for Calathea plants are bright, indirect sunlight. In the wild, they’d grow on the jungle floor getting plenty of shade from a leaf canopy above them.
Indoors, they don’t have that canopy. If placed too close to a window, the sunlight can be too intense. They may need distanced, or a screen put on the window to filter the sunlight.
Calathea Leaf Curling FAQs
Do brown tips on curled leaves recover?
No. Brown leaves won’t regain their greenery. Once brown, they should be removed.
Depending on the extent of the damage, you can either remove all or part of the damaged leaf. Removing the entire leaf lets the plant put more energy into producing new growth.
The earlier you notice leaves curling, the sooner you can rectify the growing conditions to prevent the leaves turning brown.
Can misting increase humidity enough to prevent the Calathea leaves from curling?
Not really. Misting is better for reviving curled leaves. All it really does is wets the leaves.
Humidity levels for tropical plants is reliant on moisture being in the air. Not a fine mist of water sprayed on the leaves. They absorb moisture from the air through their leaves.
To raise levels enough, you really need to have water rising into the air from below. You can do that in one of two ways. Localized humidity by grouping plants together (with or without a humidity tray) or use a humidifier to raise the room humidity.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.