Why are my calathea leaves curling?

The 4 most likely causes

The cause of calathea curling leaves usually narrows to one of the items below, ranked by how often we see each in Growli's diagnostic chats. Work down the list — most readers find their answer in the top two.

1. Low humidity (Likely)
   Calathea is native to humid environments and struggles when household humidity drops below 40%. The first sign is crispy brown leaf tips, followed by pale, curling foliage. A humidifier, a pebble tray, or grouping plants together raises local humidity meaningfully.
2. Underwatering or letting it dry too long (Likely)
   Calathea is a thirsty plant that wilts dramatically when it dries out. If the leaves are limp and the soil pulls away from the pot edge, it has gone too long between waterings. Soak the rootball thoroughly until water runs out the drainage hole.
3. Wrong light level (Possible)
   Calathea tolerates lower light than most, but tolerating is not thriving. In dim conditions it slows down, drops older leaves, and becomes more vulnerable to overwatering because the soil never dries. Give it medium indirect light, never direct sun.
4. Spider mites (in dry indoor air) (Possible)
   Calathea is a spider-mite favourite in dry indoor air. Hold a leaf up to a strong light and check the underside for fine webbing or tiny moving specks. A weekly shower in the sink and raising humidity above 50% breaks the cycle.

Why calathea in particular

Curling is the earliest distress signal a Calathea gives. The leaves fold along the midrib on cue each night through pulvinus 'motor cells' at the leaf base, so a plant that rolls tightly and stays rolled through the day has lost the internal water pressure those cells need. In this rainforest-floor genus that almost always means the air has dropped below the humidity it expects, or the rootball briefly went dry, well before any browning appears on the edges.

Normal turnover, or real trouble?

Watch the daily rhythm before you worry. A healthy Calathea furls its leaves upward and clasps them shut each evening, then reopens them flat by mid-morning, the praying motion that gives the family its name. That nightly close-and-open is a sign of health, not stress. The tell that something is wrong is leaves that stay rolled tight through the afternoon, or curl lengthwise into tubes exposing their undersides.

How to diagnose in 60 seconds

Run these quick checks before you change anything — the right fix depends on what you find.

• Is the curl upward (cupping) or downward (rolling)? Upward usually = heat or light stress; downward usually = water or pest issue.
• Check the newest leaves first — pests and herbicide damage hit new growth fastest.
• Calathea wants water when the top 1-2cm of soil is just dry, every 4-7 days. Push a finger into the mix and hold it against that: still damp well before it is due, alongside the symptom, is the overwatering signature.
• Check the underside of curled leaves for spider mites, aphids, or thrips with a phone-camera macro.

The fix — step by step

Feel the rootball with a finger rather than trusting a schedule. If it is dry, water thoroughly with room-temperature rainwater and the leaves should relax within a day. If the soil is already moist, the problem is dry air, not thirst, so group it with other plants or stand it on a wet-pebble tray and move it off any radiator. Misting alone evaporates too fast to hold humidity steady.

This is the recovery sequence Growli walks users through for calathea with curling leaves. Work through the steps in order; skipping ahead is the most common reason a plant fails to bounce back.

1. Identify the curl direction. Upward cupping points to heat or light stress; downward rolling points to water stress, pests, or cold shock. The fix depends on which one you see.
2. Inspect leaf undersides for pests. Hold a phone torch behind a curled leaf — spider mites show as fine webbing, aphids as clusters of green or black dots at the growth tips, thrips as silvery scrapes.
3. Adjust water or microclimate. If the soil is bone dry, soak calathea thoroughly. If the room is below 40% humidity and the species is humidity-loving, add a humidifier. If heat is the issue, move out of direct midday sun.
4. Treat any pests at the source. Rinse pests off in the sink, then spray leaf undersides with insecticidal soap or a neem-oil mix every 5-7 days for three weeks to break the egg cycle.
5. Wait for new growth. Curled leaves rarely uncurl. New growth will tell you if the cause is fixed — if the next set of leaves comes in flat, you have solved it.

When this can't be saved

Most cases of calathea curling leaves are recoverable, but a few red flags point to a plant that has gone past the point of return. If you spot any of these, consider propagating a clean cutting and starting over.

• New growth is thin, twisted, and fern-like (a classic herbicide-damage signature on calathea).
• Curl is paired with mosaic-pattern discolouration — that points to a viral infection with no cure.
• Every leaf curls within 24-48 hours of a single event — usually permanent shock damage.

Prevention

For calathea, the single biggest preventative is matching its native rhythm: when the top 1-2cm of soil is just dry, every 4-7 days, medium indirect light, never direct sun, and a free-draining pot with a working drainage hole. Outdoor edibles benefit from a thick mulch layer that stabilises soil temperature and moisture, both of which reduce curl. For indoor plants, keep a digital hygrometer in the room and aim for 50% humidity — humidifiers or pebble trays close the gap cheaply.

Common questions

Related guides

• What's wrong with my plant? — the diagnosis apps compared
• Is calathea toxic to cats and dogs? — pet-safe, per the ASPCA
• How often to water calathea — the watering brief
• When to repot calathea — pot size and timing
• Curling leaves on plants — the full diagnostic guide across species
• What's wrong with my plant? — Growli's flagship diagnosis index
• Calathea — yellow leaves
• Calathea — drooping
• Calathea — brown spots
• Monstera — curling leaves