Annex White book.pdf

A1.5.2.2Flowering in storage roomsA1.5.2.2.1 Planting density in traysIn forced cultivation, it is important that the trays should be piled upin order to maintain as much bulbs as possible in limited space.Planting density depends on the size of the bulb. Given the fact thatthe recommended bulb diameter should be 30 mm or more, an averageof 472 bulbs is needed per m 2 (Valero et al, 2004). The bulbs remain inthe trays until the end of the flowering process and are planted directlythereupon, in the field in order to propagate.A1.5.2.2.2 UnderlayThe trays, where the bulbs are placed, are covered with an inertunderlay such as micanite that enables flattening. Its purpose is to holdhumidity and supply the growing layer for sprouts and roots.A1.5.2.2.3 Irrigation controlWhen climate conditions allow the transition from storage to flowering,then the time is appropriate for watering. Irrigation frequency andintensity depended largely on the underlay quality and the needs of thecultivation. Flowering initiation can be predicted with very narrow errormargin according to the first irrigation.A1.5.2.2.4 Temperature and light controlA temperature between 17 and 18 o C is suitable for flowering. Thetime needed for flower development at this temperature, varies accordingto storage duration. After long storage the flowers grow faster (Valeroet al, 2004).Bulbs do not need light except during flowering period, in order toavoid whitening (excessive and unbalanced leave and stamen developmentthat could use up all reserves and hinder flower growth).A1.5.2.2.5 Flowering periodFlowering may last around 100 days. The average flowering duration foreach bulb “compartment” is 13 days (Valero et al, 2004). Bulb production ineach tray is slow during the beginning and the end of the flowering period,while up to three maximum flowerings are possible during this time.119