Brown Tips on calathea
What's Happening
Brown leaf tips on Calathea result from mineral salt accumulation at leaf apices where water transpires and evaporates, leaving calcium, magnesium, and sodium deposits. These salts create osmotic stress that dehydrates leaf cells, causing tissue death at the growing tip. The pattern differs from fungal disease: mineral burn shows uniform browning at the very tip progressing backward, while fungal issues create irregular spots or patches. Hard water with >120 ppm dissolved solids accelerates this process significantly.
How to Fix It
- 1
Switch to distilled, rainwater, or filtered water immediately
- 2
Flush soil thoroughly with 3x pot volume of distilled water to leach salts
- 3
Trim brown tips with sterile scissors following natural leaf shape
- 4
Repot in fresh potting mix if white salt crust visible on soil surface
- 5
Maintain proper humidity to reduce transpiration rate and mineral concentration
How to Prevent It
Use only low-mineral water sources (distilled, rainwater, RO filtered). Flush soil monthly with distilled water to prevent salt accumulation. Avoid softened water which adds sodium. Test water hardness - aim for <50 ppm total dissolved solids.