Calathea: tap water damage — what does it look like?

Crisp brown margins around an otherwise green leaf, often with a thin yellow halo. Uniform across the whole plant rather than isolated. Switch to distilled, filtered or rainwater. Existing damage will not reverse — judge recovery by new leaves only.

Calathea: low humidity — what does it look like?

Edges curling inward, crisping at the tips, leaves failing to unfurl fully. Needs genuinely humid air, not occasional misting. A pebble tray or humidifier is the actual fix.

Calathea: root rot from staying wet — what does it look like?

Whole leaves yellowing and drooping without recovering overnight, soil permanently damp. Calathea wants consistently moist, never wet. The margin between the two is genuinely narrow.

Field Guide/Calathea

What went wrong

Calathea

Calathea / Goeppertia

Beautiful, and quietly furious about your tap water.

Calathea is the plant most likely to have been killed by something its owner never suspected. It is unusually sensitive to the fluoride, chlorine and dissolved salts in ordinary tap water, and the damage shows up as crisp brown leaf edges that look exactly like underwatering. The natural response is to water more, with the same water, which accelerates it.

Add genuinely high humidity requirements and a strong dislike of cold drafts, and you have a plant that fails slowly and confusingly in an average heated home.

Usually one of these

3 Likely Causes

Ranked by how often it is actually this.

01
Tap water damage
The signature cause
What you saw
Crisp brown margins around an otherwise green leaf, often with a thin yellow halo. Uniform across the whole plant rather than isolated.
What it means
Switch to distilled, filtered or rainwater. Existing damage will not reverse — judge recovery by new leaves only.
02
Low humidity
Very common in winter
What you saw
Edges curling inward, crisping at the tips, leaves failing to unfurl fully.
What it means
Needs genuinely humid air, not occasional misting. A pebble tray or humidifier is the actual fix.
03
Root rot from staying wet
Common, often from over-correcting
What you saw
Whole leaves yellowing and drooping without recovering overnight, soil permanently damp.
What it means
Calathea wants consistently moist, never wet. The margin between the two is genuinely narrow.

The question you actually have

Dead or dormant?

Calatheas move their leaves on a daily rhythm, rising at night and lowering by day — a plant still doing this is alive regardless of how ragged it looks. If the foliage is entirely dead, check for firm rhizomes below the soil; calathea frequently resprouts from the base after losing every leaf, particularly in spring.

If it did not make it