The process where water is absorbed by roots and released as water vapor from leaves, accounting for most water used by plants and cooling plant tissues.
In plain terms
Plants absorb water through roots and release most of it as water vapor through leaf stomata (transpiration). It's not waste—it cools plants and transports nutrients from roots to shoots. Dry air and warm temperatures increase transpiration (water loss). High humidity reduces transpiration (less water loss). Understanding transpiration explains why wilting happens in hot, dry weather even with watering.
Why this matters
Understanding transpiration explains water needs and wilting under stress. It also explains why humidity and wind affect plant water requirements.
In practice
Examples
Hot, dry day: high transpiration; plants wilt despite watering; shade and humidity help.
Cool, humid day: low transpiration; same watering meets plant needs.
New transplant in sun: high transpiration, damaged roots can't supply water fast enough; wilting; shade reduces transpiration, recovery occurs.
Windy day: transpiration increases dramatically; plants need more water despite cool temperature.
Practical applications
Water more frequently in hot, dry, windy weather (high transpiration).
Reduce water loss through mulch and shade in extreme heat.