Why Are My Kalanchoe Leaves Curling?

Overwatering and root rot

Kalanchoe is a succulent and stores water in its leaves and stems. It is far more likely to be killed by too much water than too little. When the roots sit in waterlogged compost they quickly rot, losing the ability to absorb water and nutrients. The plant responds with yellowing, curling, and eventually collapsing leaves even though the compost may still be wet.

Lift the pot and feel the weight. A waterlogged pot is surprisingly heavy. Then remove the plant and check the roots: healthy roots are white and firm, while rotten ones are brown or black and feel mushy or hollow. A faint unpleasant smell is another tell-tale sign of root rot.

What to do

• Remove the plant from its pot and cut away all blackened or mushy roots using clean, sharp scissors.
• Allow the plant to sit out of its pot in a shaded, airy spot for 24 hours to let the damaged tissue dry slightly before repotting.
• Repot into fresh, well-draining compost (a cactus and succulent mix is ideal) in a clean pot with drainage holes.
• Do not water for one week after repotting, then resume watering only when the top 2 to 3 cm of compost feel dry.
• Empty saucers after watering so the plant is never sitting in standing water.

Too much direct sunlight

Kalanchoe thrives in bright light but can struggle with intense, direct afternoon sun through glass, which is often far stronger than outdoor sun and can heat the leaves rapidly. Leaves exposed to excessive sun intensity may curl downward or inward, develop bleached or papery patches, and turn pale yellow-green rather than their healthy deep green.

Morning sun from an east-facing window or filtered light from a south-facing window through a net curtain is the ideal balance. If the plant has been on a very sunny sill during a heatwave, that is the most likely trigger.

What to do

• Move the plant to a position with bright, indirect light or gentle morning sun rather than intense afternoon direct sun.
• Use a sheer curtain or blind to filter midday and afternoon light on south or west-facing windowsills.
• Scorched leaves will not recover but healthy new growth will emerge once light levels are corrected.

Underwatering

Although kalanchoe tolerates drought better than most houseplants, prolonged underwatering eventually causes the leaves to shrivel, wrinkle, and curl inward as the plant uses up its stored water reserves. This type of curling is accompanied by leaves that feel thin, leathery, or slightly rubbery rather than firm and plump, and compost that is completely dry all the way through.

Kalanchoe is much more forgiving of underwatering than overwatering, but in warm summer conditions a plant in a small pot can dry out faster than expected, especially if it is in a sunny spot.

What to do

• Water thoroughly until it runs freely from the drainage holes, then discard any water that collects in the saucer.
• If the compost has completely dried and is pulling away from the pot sides, soak the pot in a bowl of water for 15 to 20 minutes to rehydrate the root zone evenly.
• In summer, check the compost more frequently and water as soon as the top 2 to 3 cm are dry rather than waiting until the whole pot has dried out.

Cold damage

Kalanchoe is a tropical plant that is not cold-hardy. In the UK it must be kept indoors year-round and protected from temperatures below about 10 degrees Celsius. Exposure to draughts from badly fitting windows, being left on a cold windowsill overnight in winter, or a brief spell in an unheated conservatory can all cause the leaves to curl, develop translucent or water-soaked patches, and eventually collapse.

Cold damage often appears on the side of the plant closest to the cold air source and may not become fully apparent until a day or two after the cold event.

What to do

• Move the plant to a consistently warm spot, ideally between 15 and 25 degrees Celsius, away from exterior walls and draughty windows.
• Do not place kalanchoe on windowsills in winter unless you are confident the window is well-insulated and sealed.
• Remove leaves that have turned translucent, mushy, or collapsed, as they will not recover and may encourage fungal rot if left on the plant.
• Once the plant is warm and stable, reduce watering slightly while it recovers, as cold-damaged roots are temporarily less efficient at uptake.

Mealybug and aphid infestation

Mealybugs and aphids both feed on kalanchoe sap, and a significant infestation causes leaves to curl, pucker, and distort as the plant responds to repeated puncturing of leaf tissue. Mealybugs are most often found at leaf axils and on the undersides of leaves where they look like small tufts of white waxy fluff. Aphids cluster along new growth and flower stems, often appearing in green, black, or grey colonies.

Check closely under curled leaves and at joints between leaves and stems. A sticky residue (honeydew) on the leaves or pot surface is another sign of active pest feeding.

What to do

• Isolate the affected plant immediately to prevent pests spreading to nearby houseplants.
• For mealybugs, dab each visible pest with a cotton bud dipped in rubbing alcohol (isopropyl alcohol), then follow up with a spray of diluted neem oil or insecticidal soap every five to seven days for three to four weeks.
• For aphids, wipe off heavy infestations with a damp cloth, then treat with insecticidal soap spray, repeating every five days until the population is eliminated.
• Once the infestation is under control, damaged or distorted leaves can be removed to improve the appearance of the plant.

Frequently asked questions

Why are my kalanchoe leaves curling?

Kalanchoe leaf curling is most often caused by overwatering, which leads to root rot and prevents the plant from drawing up water properly. Too much direct afternoon sun, underwatering in summer, and mealybug or aphid infestations are also common causes.

How much should I water kalanchoe?

Water thoroughly when the top 2 to 3 cm of compost feel dry, then allow it to drain fully and empty the saucer after 30 minutes. In winter, water even less frequently as the plant slows down almost to dormancy.

Why are kalanchoe leaves curling and turning yellow?

Yellow curling leaves usually indicate overwatering or root rot. Remove the plant from its pot and inspect the roots. Healthy roots are white and firm; roots damaged by rot are brown, black, and mushy.

Can kalanchoe survive frost?

No. Kalanchoe is frost-tender and any exposure to temperatures below 5 degrees Celsius will cause leaf damage, curling, and tissue collapse. In the UK, always keep kalanchoe indoors through winter and well away from cold windowsills overnight.