A symptom is an observation—not a diagnosis
Observation-First Diagnostic Center
Verify measurement systems, compare location and time patterns, preserve records, and test more than one plausible cause before acting.
Environment / VPD
Map canopy zones and timing; verify sensor location, RH, air/leaf temperature and VPD inputs.
Lighting
Map symptoms against fixtures and canopy position; verify meter, PPFD grid, DLI inputs and actual schedule.
Core rules
- Photograph affected and unaffected tissue consistently before changing the system.
- Verify instruments before interpreting plant response.
- Compare affected versus unaffected locations, time trends, developmental stage, and recent changes.
- Change one controlled variable at a time when safe and appropriate.
- Stop when safety, instrument integrity, contamination, or rapid crop-loss boundaries are crossed.
Continue learning
Use the visual library, THC Grow Doc, measurement guides, and records together. One symptom or one number is not a complete diagnosis.