Why Are My Gasteria Leaves Curling?

Overwatering and root rot

Overwatering is the most common cause of problems in gasteria. The thick, fleshy leaves store water and the plant's natural habitat is rocky, fast-draining ground that dries out quickly between rain events. When kept in consistently moist compost, the roots rot and the plant loses the ability to absorb water and nutrients even though plenty of moisture surrounds the roots. The leaves begin to curl, turn pale or translucent at the base, and may feel soft and slightly waterlogged rather than firm and plump.

A gasteria in a plastic pot with moisture-retentive compost, watered on a regular weekly schedule, is the classic overwatering setup. Slow-growing plants use water slowly and do not need frequent attention.

What to do

• Remove the plant from its pot and examine the roots. Trim away any darkened, mushy, or hollow roots with clean scissors.
• Allow the plant to air-dry in a shaded location for 24 hours before repotting into fresh, gritty succulent compost in a terracotta pot with drainage holes.
• Do not water for one to two weeks after repotting.
• Going forward, water only when the compost has dried out completely, feeling the weight of the pot to judge moisture rather than relying on a schedule.

Too much direct sunlight

Gasteria is one of the few succulents that genuinely prefers indirect light over direct sun. In its natural habitat it grows in the shade of shrubs and in rocky overhangs where it receives bright but filtered or reflected light rather than hours of direct sun. When placed in a sunny window with intense afternoon light, the leaves curl, turn red or orange (a stress pigment response), and the tips can dry out and shrivel.

This is one of the most common mistakes made with gasteria, since many gardeners assume that all succulents need maximum sun. Unlike echeveria or aloe, gasteria will always look better in bright indirect light than in a blazing south-facing window.

What to do

• Move the plant to a position with bright indirect light. An east-facing window, or a position set back from a south-facing window, is ideal.
• North-facing windows, which would be unsuitable for most succulents, work well for gasteria provided the light level is reasonable.
• Once moved to appropriate light, the reddish colour will gradually fade as new green growth replaces the stressed foliage. Existing red-tinged leaves will not turn green again but the plant will produce healthy new growth.

Underwatering

Although gasteria stores water in its leaves and is drought-tolerant, it will eventually show signs of stress if deprived of water for too long. The leaves shrink slightly, feel less firm than usual, and may curl inward as the stored water is used up. Unlike overwatering damage, underwatering curling is accompanied by leaves that feel noticeably less plump and a compost that is completely dry and lightweight.

Gasteria grows slowly, which means it uses water slowly, but it still needs watering periodically through the year. In a centrally heated home in winter, it may dry out faster than expected.

What to do

• Water the plant thoroughly, allowing water to drain freely from the bottom, then discard the drainage.
• If the compost has dried out completely and water is not penetrating, bottom-water by placing the pot in a shallow bowl of water for 20 minutes.
• Within a week of adequate watering, the leaves should begin to firm up again. Full recovery of plumpness may take two to three weeks.

Temperature extremes

Gasteria is sensitive to frost and to sudden cold draughts. As a plant from the warmer parts of southern Africa, it should be kept above 10 degrees Celsius in winter. A position on a cold windowsill in winter, where the temperature drops sharply at night, can cause the outer leaves to turn translucent and soft, eventually curling and collapsing. Equally, very high temperatures combined with intense sun create stress that causes leaf curling, particularly at the tips.

What to do

• Keep gasteria at temperatures between 10 and 27 degrees Celsius year-round.
• Move plants away from cold windowsills in winter, or insulate beneath the pot with a cork mat or folded newspaper.
• Cold-damaged outer leaves can be removed at the base once the plant is in a warmer position, as they will not recover.
• In summer, if the plant is in a very warm room or conservatory, ensure good ventilation and move it away from glass that concentrates heat.

Mealybug infestation

Mealybugs are the most common pest of gasteria and its relatives. They congregate in the tight spaces between the leaves at the base of the plant and in the leaf axils, where their white waxy coating makes them look like small tufts of cotton. Sustained feeding weakens the plant, causes leaves to discolour and curl, and leaves behind sticky honeydew that can attract sooty mould. Because gasteria is slow-growing and compact, mealybug colonies can become established before the damage is noticed.

What to do

• Isolate the plant immediately to prevent mealybugs spreading to neighbouring succulents.
• Dab each visible mealybug with a cotton bud soaked in 70 percent isopropyl alcohol. Check between every leaf carefully, as a single missed cluster will allow the infestation to recover.
• Follow up with a spray of diluted neem oil or insecticidal soap over the whole plant, repeating every five to seven days for three to four weeks to catch any hatchlings from eggs the alcohol did not reach.
• Check the roots when repotting: root mealybugs (white waxy deposits on the roots) sometimes accompany leaf infestations and require a fresh compost change and root wash to eliminate.

Frequently asked questions

Why are my gasteria leaves curling?

Gasteria leaves curl most commonly from overwatering or too much direct sun. Unlike many succulents, gasteria is adapted to grow in the shade of rocks and shrubs in southern Africa and dislikes intense direct sunlight. Overwatering leads to root rot, which prevents water uptake and causes the fleshy leaves to curl and become soft.

How often should I water gasteria?

Allow the compost to dry out completely between waterings, then water thoroughly. In summer, this may be every two to three weeks; in winter, once a month or even less. Gasteria, like its relatives haworthia and aloe, is far more likely to be harmed by too much water than too little.

Can gasteria tolerate shade?

Yes, gasteria is one of the most shade-tolerant succulents available. It grows naturally under shrubs and in rock crevices where direct light is limited. It can thrive in north-facing windows and positions that most other succulents would find too dark. This makes it one of the best succulents for lower-light homes.

Why are gasteria leaves turning red and curling?

Reddening combined with curling is a classic sign of too much direct sun. The red colour is a stress pigment (anthocyanin) that the plant produces in response to intense light exposure. The curling accompanies the colour change as the leaves try to reduce the surface area exposed to light. Move the plant to bright indirect light to reverse the reddening.