Phenology of potted Zinnia 'Profusion Cherry' grown in a greenhouse with plastic cover was evaluated for weekly sowing dates from: 2/4/05 to 6/17/05. The length of plant cycle was influenced by air temperature and photoperiod. The average length of the phase sowing to first open flower varied from 39 days for the sowing dates of 03/11/05 and 03/18/05 to 63 days for 06/10/05. It was also showed that estimates of the length (D) of the period sowing to first open flower could be obtained by the following equation: 1/D = 0.019108 + 0.001968 T - 0.00352 F (R² = 0.99) where, T is the mean air temperature (ºC) and F is the mean photoperiod (hours).
cycle; temperature; photoperiod
