Why does my calathea have curling leaves?

On a calathea the leaves roll inwards along their length, the two edges curling towards each other so that the round leaf becomes a trough or a tube. The surface of the leaf looks duller than usual, and it may feel thinner and drier to the touch. Do not mistake this for the normal movement: the RHS notes that the leaves fold upwards at night like hands in prayer.

The most likely cause, as the entry says, is that the compost has dried out, or the air is too dry. The NC State plant toolbox says the leaves can curl from lack of water or from low humidity. This is a plant that wants its compost kept lightly moist, so it is watered about every 5 days in the growing season and 9 in winter, and the RHS says never to let the compost dry out completely.

To confirm it in a minute, check the leaf in the morning rather than at night, because the normal movement is nightly. Then push a finger into the compost and lift the pot. Dry compost and a light pot say thirst. If the compost is still moist, think about the air: curling that began when the heating came on, on a plant near a radiator, points to the air.

Two other causes are worth ruling out. Heat or strong sun curls leaves during the hottest part of the day, and they relax again by evening, which tells you the place is wrong. The entry says direct sun bleaches the silver banding within days. And cold gives a darker, slightly translucent curl on a plant near a window in winter, and the RHS wants it at 16 degrees or above.

If thirst was the cause you will see the leaves open the day after a proper drink. If the air was the cause, give the plant a week or two in the humid spot and watch whether the newest leaves unroll flat.

What this plant wants

The fix

Water more evenly and move it somewhere more humid. Leaves that curl from thirst open again within a day of watering.

Read on

Leaves curling inwards or under

The same sign on any plant, with the causes in the order they are likely.

Calathea care

Light, water, feeding, repotting and the rest of the entry.

Check it in the diagnoser

Opens with the plant, the part and the sign already chosen.