Symptom differential
Upward Curl / Tacoing
Leaf margins curling upward can be associated with high radiant load, heat, low humidity, airflow, root-water limitations, genetics, or other stress. It should be interpreted alongside leaf temperature and canopy position.
Pattern questions
- Is the symptom concentrated near the light or hottest canopy zone?
- Are leaf temperatures elevated relative to air?
- Does curl improve during lower-demand periods?
- Are roots and substrate moisture adequate?
Plausible cause categories
- High light or radiant load
- Heat stress
- High evaporative demand
- Root-water limitation
- Airflow exposure
- Genetic leaf posture
Discriminating checks
- Measure PPFD and leaf temperature
- Map temperature/RH and airflow
- Check substrate moisture and roots
- Compare shaded or lower-canopy leaves
Red flags
- Bleaching or tissue death
- Persistent wilt
- Root failure
- Symptoms continuing after environmental demand is reduced
Visual study guide
- Tacoing posture plate
- Leaf-temperature concept
- High-light canopy map
- Airflow exposure comparison