General crop chilling-injury principles, cold and wet root-zone exposure, low-temperature stress around germination and establishment, and the importance of temperature history when interpreting injury.
Abiotic disorders
Cold & Chilling Stress
Low tissue or root-zone temperatures can slow metabolism, water uptake, and growth. Chilling symptoms overlap with nutrient and root problems, so temperature history and location matter more than leaf color alone.
What to look for
- Slowed growth following cold nights, cold irrigation solution, or cold root-zone conditions
- Temporary wilt, discoloration, or pigmentation associated with temperature drops
- Symptoms strongest near cold walls, floors, intakes, or exposed outdoor locations
- Recovery lag even after air temperature improves
Important look-alikes
- Nutrient availability problems
- Root disease
- Drought stress
- Genetic anthocyanin expression
How to confirm
- Review minimum air, leaf, and root-zone temperatures
- Map cold locations rather than relying only on daytime averages
- Inspect roots and irrigation temperature
- Compare affected plants with protected plants of the same cultivar
Management principles
- Restore stable temperature conditions without abrupt extremes
- Do not diagnose cold-associated pigmentation as a nutrient shortage from color alone
- Protect root function as well as the canopy
- Assess recovery using subsequent growth
Prevention
- Monitor nighttime and root-zone minimum temperatures
- Avoid cold irrigation shocks where practical
- Identify cold-edge microclimates
- Harden plants gradually when transitioning outdoors
Visual study guide
- Cold-zone room map
- Chilling versus nutrient differential
- Root-zone temperature timeline
- Recovery growth comparison
Evidence & further reading
Sources connected to this lesson
These references support specific biological, diagnostic, environmental, or process concepts used in this lesson. They are not a substitute for crop-specific testing or local regulatory guidance.Cannabis gas exchange, photosynthesis, transpiration, stomatal conductance, PPFD, temperature, and carbon-dioxide response under measured conditions.