Brown tips and edges

Brown tips are cosmetic on their own, but they're the plant telling you something about water. The brown won't turn green again; the aim is clean new growth.

How to tell which cause it is

• Crispy tips, worst in winter, near a radiator: dry air. Calatheas, ferns and palms show it first.
• Brown edges after the soil dried out completely: irregular watering.
• Brown tips plus a white crust on the soil or pot rim: salt build-up from fertiliser or hard water.
• Tips browning on a spider plant, dracaena or calathea despite good care: sensitivity to fluoride and chlorine in tap water.
• Dry, pale-brown patches on the side facing the window: sunburn.
• Soft, dark brown patches with wet soil: not dryness but overwatering. See yellow leaves and root rot.

How to fix it

Trim the brown with clean, sharp scissors, following the leaf's natural shape and leaving a thin line of brown so you don't cut into healthy tissue.

Dry air: move plants away from radiators and heating vents, and group them together. A humidifier helps more than misting, which lasts minutes.

Uneven watering: water thoroughly when the top of the soil is dry, rather than little and often or rarely and in a panic.

Salts: flush the soil: run water through the pot for a minute or two and let it drain. Feed at half strength, and only in the growing season.

Tap water: for sensitive plants use rainwater, filtered water, or tap water left out overnight.

How to prevent it

Keep watering even, feed lightly, flush the soil every three or four months, and give humidity-loving plants the brightest humid room you have — often the bathroom or kitchen.