Effect of planting dates on growth and flowering of selected rainy season annuals

The present investigation was conducted at the experimental farm of Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan (Himachal Pradesh), to evaluate the performance of eight rainy season annuals under different planting dates. The study involved tall zinnia, dwarf zinnia, balsam, gomphrena ‘pink’, gomphrena ‘magenta’, cosmos, African marigold, and china aster, planted on three dates: June 3rd, July 3rd, and August 3rd. Results revealed that tall zinnia recorded the maximum plant height, while gomphrena ‘pink’ showed the widest plant spread and longest flowering duration. Balsam exhibited the earliest flower bud initiation, earliest flowering, highest number of flowers per plant, and the highest flower yield both per plant and per plot. Tall zinnia produced the largest flower size. Among the planting dates, June 3rd (planting date 1) resulted in the best overall performance, including maximum plant height, plant spread, flower size, flowering duration, flower count, and yield per plant and per plot. In contrast, the earliest flower bud initiation and flowering were observed in the August 3rd planting (planting date 3). The study highlights the importance of cultivar selection and optimal planting time for maximizing growth and floral yield of rainy season annuals.