Systemic Granules on calathea
What's Happening
Primary issue stems from overwatering in winter UK conditions: larger pot post-repot retains moisture longer due to cooler temps (slower evaporation/transpiration), causing root stress, yellowing, and eventual crispy edges. Conflicting advice overlooks Calathea's high humidity needs (60-80% ideal); humidifier proximity insufficient without verification, as indoor winter air is arid (<40% RH). Prior summer repot shock compounded by poor-draining mix led to chronic tip burn from inconsistent moisture/humidity.
How to Fix It
- 1
Verify soil dryness: insert finger 2 inches deep; water only if dry and leaves droop (Calathea's nyctinastic signal).
- 2
Bottom water sparingly (every 10-14 days in winter), ensuring full drainage.
- 3
Enhance humidity: use hygrometer to confirm >60% RH; add pebble tray or daily misting if humidifier ineffective.
- 4
Inspect roots for rot during next repot if yellowing persists; trim only irretrievable leaves to redirect energy.
- 5
Maintain indirect light, 18-24°C, no drafts; use rainwater or filtered water to avoid fluoride sensitivity.
How to Prevent It
Switch to airy aroid mix with perlite; monitor with hygrometer/soil probe; adjust watering seasonally (reduce 50% in winter); group with other high-humidity plants.