When preparing our flower bulbs, we simulate winter in a cold storage room. Preparation primarily occurs with bulbs intended for tulip hatchery. A tulip requires a cold period for stem elongation and flowering. Normally, tulips experience their cold period outdoors in the ground during the winter. By artificially providing tulips with a cold period, they bloom earlier than their natural flowering time. The cold period for tulips begins at a temperature below nine degrees Celsius. The bulb requires a cold period of 10 to 16 weeks. Once the tulips have experienced the cold, they are ready for forcing. This way, tulips are available throughout the year.
Developmental Stage
Different temperatures are maintained for tulip bulbs. For flower development within the bulb, we begin with a warmer temperature. To determine the correct temperature, it is always necessary to first identify the developmental stage of the flower. The developmental stages are: I, II, P1, A1, A2, and G. This allows us to determine the right temperature and duration in the cold storage room.
Stage I
Leaf-forming period. No flower formation yet; the growing point is slightly indented.
Stage II
Onset of flower formation. The growing point is now bulbous.
Stage P1
At this stage, the outer circle of petals is formed.
Stage P2/A1
At this stage, the inner circle of petals is formed.
Stage A2
The inner circle of stamens is developed.
Stage G
The pistil is formed.