How does temperature affect seed germination, flowering, and plant growth?

Temperature is a critical environmental factor that regulates the rate and extent of plant growth, seed germination, and flowering.1

Seed Germination

Temperature influences germination through specific requirements for dormancy release and optimal growth conditions. Many seeds require a period of cold exposure, known as stratification, to overcome dormancy and ensure uniform germination. Additionally, some species require a modest daily fluctuation between higher daytime and lower nighttime temperatures to trigger germination, which serves as an ecological cue for the seed's depth in the soil. While many seeds are resistant to extreme temperatures, optimal germination temperatures vary widely by species, ranging from as low as 1 °C to as high as 42 °C.2

Flowering

Many plants rely on vernalization, a process where exposure to low temperatures stimulates the transition from vegetative growth to flowering. This ensures that blooming occurs during favorable conditions, such as spring. Conversely, devernalization can occur if plants are exposed to high temperatures, reverting them to a nonflowering state.3

Plant Growth

Temperature directly affects the biochemical reactions necessary for life; as temperatures decrease, metabolism slows significantly. Thermoperiodicity describes how plants respond to alternating warm and cool periods, with many species requiring cooler nights for optimal growth and flower production. Extreme temperatures, however, can cause physiological damage, such as leaf scorching, stunting, or tissue necrosis.145