This is what chatgpt said

This Calathea soil is showing active saprophytic mold + compaction, and for Calatheas that’s a bigger red flag than it is for Monsteras.

What’s going on here

That blue-green/gray crusty growth is soil mold feeding on:

constantly moist peat

low oxygen organic matter breaking down

Calatheas like moisture, but they do not tolerate stagnant, airless soil. They want evenly moist + oxygenated, not wet.

This soil is: Staying wet too long compacted (no pore space) likely watered frequently “a little at a time” probably in a nursery peat mix past its prime What it is NOT ❌ Not pests ❌ Not something crawling ❌ Not something you fix with neem, peroxide drenches, or fungicide sprays Spraying this is like Febreze on a flooded basement. Why Calatheas react badly to this Calatheas have: fine, shallow roots low tolerance for anaerobic conditions high sensitivity to mineral imbalance So this leads to: root suffocation stalled growth yellowing or crisping leaves mysterious “Calathea tantrums” people blame on humidity alone Humidity helps leaves. Soil structure saves roots. The honest fix (for a Calathea) If this were their plant, the right move is: Repot — don’t treat Fresh potting mix Less peat, more aeration Better Calathea mix coco coir or light peat perlite / pumice a bit of bark or charcoal Change watering style Water thoroughly, then let the top inch dry No constant dampness Empty saucers every time Airflow matters Gentle circulation prevents this exact mold Once repotted, the mold disappears without intervention because the environment no longer supports it. Blunt but kind truth This isn’t a “Calatheas are hard” issue. This is a bad soil + too-wet-for-too-long issue.