What type of plants require longer daylight hours than a certain threshold to produce flowers?

Long-day plants are those that require longer daylight hours—typically more than 12 hours of light per day—to initiate flowering. These plants have adapted to bloom during the late spring and summer months when days are longer. The increased daylight triggers hormonal changes within the plant that lead to the development of flowers. This adaptation allows them to maximize their reproductive potential during a season that provides ample sunlight and favorable growing conditions.

In contrast, short-day plants flower when the daylight period falls below a certain threshold, typically less than 12 hours. Annual plants complete their life cycle in one growing season, and biennial plants generally require two growing seasons to flower, making them independent of the day length condition in flowering pathways. Understanding the specific light requirements of these plants is crucial for those interested in horticulture and agriculture, especially when planning planting schedules or managing growth conditions for different species.