Curling leaves are one of the most common signs that something is not quite right with a Calathea. In most cases, the plant is struggling to get enough moisture, either because the roots are too dry or the surrounding air lacks humidity. Dry compost is the most common culprit, but low humidity and a build-up of minerals from hard tap water can also cause the leaves to curl.
Calatheas, now often sold under the genus Goeppertia, are rainforest plants that are accustomed to warm, humid conditions and consistently moist soil. When conditions become too dry, their leaves can curl inwards as a natural response to reduce moisture loss.
The key is to identify what is causing the curling before reaching for the watering can or humidifier. Read through the most common causes below and look for the signs that best match your plant, then tackle that specific problem rather than changing several things at once.
Dry Soil
If the leaves curl and the top of the compost feels dry, the plant is simply too dry. Calathea likes its mix kept lightly and evenly moist, never bone dry and never waterlogged. In a warm room that usually means watering every 5 to 7 days in summer and a little less in winter.
Check with a finger before you water: if the top 2 to 3 cm is dry, water thoroughly and let the excess drain. Leaves that have curled from thirst usually relax within a day of a good drink. For the underlying watering routine, our tip on how often to water a houseplant is a useful starting point.
Low Humidity
Calathea comes from humid forest floors and struggles in dry indoor air, especially near radiators or in winter. If the soil is moist but the leaves still curl and the edges go crisp, humidity is the likely culprit.
Raise it properly: stand the pot on a pebble tray, group it with other plants, or run a humidifier in the room. A naturally humid spot such as a bright bathroom or kitchen also helps. We do not recommend misting; it barely lifts humidity and can encourage leaf spotting on Calathea. Our guide to increasing humidity for houseplants covers the options in more detail.
Hard or Chlorinated Tap Water
Calathea is sensitive to the minerals, chlorine and fluoride in hard tap water. Over time these build up and show as curling, browning edges and pale marks on the leaves.
If you are in a hard-water area, switch to rainwater, filtered water, or tap water left to stand overnight. It is one of the single biggest improvements you can make for a fussy Calathea. See whether you can use tap water for houseplants for the full picture.
Too Much Light or Heat
Direct sun and hot, dry spots make Calathea curl and fade to protect itself. It wants bright, indirect light, not a sunny windowsill. If the plant sits in strong afternoon sun or right above a radiator, move it somewhere brighter but out of direct rays and away from heat sources.
Cold and Draughts
Sudden cold, a draughty doorway or a chilly windowsill in winter can also trigger curling. Calathea likes steady warmth, ideally 18 to 24C, and dislikes being moved between very different conditions. Keep it away from draughts and cold glass.
How to Fix Curling Calathea Leaves
- Feel the soil. If dry, water thoroughly with room-temperature water and let it drain.
- If the soil is moist, look at humidity and water quality next.
- Switch to rainwater or filtered water if you are on hard tap water.
- Move the plant out of direct sun and away from radiators and draughts.
- Give it a week of steady conditions before judging progress. New leaves should open flat.
Older leaves that have browned badly will not fully recover, so it is the new growth you are watching. If curling comes with crispy brown edges, our tip on brown leaf tips is worth a read alongside this one.