The number of days to visible buds and to flower was affected by temperature but not by irradiance treatments given prior to (3 L) the 3-leaf-pair stage. At this stage of development, flower buds may already be initiated and, therefore, development is largely dependent on temperature rather than irradiance. Once flowers are formed, it is important to avoid high temperatures (>27.C) to not only prevent the delay of flower bud development, but also prevent flower bud loss. Therefore, optimum temperatures for speed of flowering and maximum flower number may be around 24.27/16.C (D/N). For gloxinia, 24.29.C/15.18.C (D/N) was reported to be optimum for forcing (Aulenbach, 2009). The number of flowers in three cultivars of Achimenes was increased as day temperature was increased from 17 to 25.C for 10 weeks with plants that had not yet reached the visible buds stage (Vlahos, 1990b).