Frost injury symptoms depend on which factor?

• A. Timing
• B. Soil pH
• C. Plant height
• D. Moisture level only during summer

Answer: (A)

Frost injury depends on when the frost occurs relative to the plant’s readiness and growth stage. The plant’s level of hardiness changes with the season: after a period of acclimation in fall, tissues become more tolerant of freezing, while during rapid new growth or before full hardening, tissues are much more susceptible. A frost hitting during a vulnerable stage—such as when buds, young shoots, or expanding leaves are forming—will show injuries like browning, necrosis, or tissue collapse more readily than a frost that occurs after the plant has hardened. The exact symptoms will often appear first on these tender tissues because they are the least frost-tolerant at that moment.

So the timing of the frost, in relation to the plant’s developmental stage and acclimation state, best explains why frost injury symptoms appear and how severe they are. Soil pH, plant height, or moisture levels during summer don’t determine the injury pattern in the same way, even though moisture and exposure can influence severity after the fact.