Influence of different bulb size and planting time on growth, morphology, and flower quality of Narcissus tazetta under greenhouse conditions

Narcissus tazetta L. is an important ornamental geophyte widely cultivated for cut flower and bulb production; however, optimizing bulb size and planting time is essential to improve flower quality and production efficiency under greenhouse conditions. This study investigated the effects of bulb size and planting date on vegetative growth, flowering, and bulb characteristics during the 2022-2023 growing season. Bulbs collected from the natural flora of Hatay, Türkiye, were classified into four circumference groups (≤ 10 cm, 10-12 cm, 12-14 cm, and ≥ 14 cm) and planted on 15 September, 30 September, and 15 October at 15-day intervals in a greenhouse. Emergence time, flowering time, vegetative growth traits, flower quality parameters, bulb characteristics, and bulblet formation were evaluated. Bulb size significantly affected most measured variables. Although emergence occurred in all treatments, bulbs ≤ 10 cm did not flower at any planting date. Bulbs ≥ 10-12 cm were suitable for bulb production, while 12-14 cm and ≥ 14 cm bulbs were more appropriate for commercial flower production. The second and third planting dates improved flower quality and extended the harvest period. Optimizing bulb size and planting time can therefore enhance flower quality and prolong flowering duration in greenhouse-grown N. tazetta.