In this section, you will find the growing methods in use, the growing techniques, crop protection, disease control and variety choice of tulips, hyacinths and narcissus.

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3.4 Determination of flowering time When the first flowers are harvested depends on, amongst others, the time the cultivar reaches Stage G. As soon as this occurs, bulbs are stored at the intermediate temperature for at least one week. The intermediate temperature is immediately followed by the cold treatment. Before 15 September all bulbs must be cooled dry, after that date you may choose to provide the cold period to dry bulbs or to bulbs planted in trays. The bulbs must remain in the trays for at least 6 weeks. By adding up the total time spent in the greenhouse, the harvesting date can be calculated. The first bloom can be calculated from the time Stage G is reached, alternatively the beginning of the cold period may also be determined based on the required flowering time. For example, the desired flowering period is around 6 March, minus 21 greenhouse days gives a housing date of 14 February; deduct 16 cold weeks, which means that the cold phase must start from 25 October. Here, too, part of the required cold may be given to the dry bulbs, if the bulbs are to be stored in a planted condition for around 6 weeks and the dry cold period is completed at the latest around 15 December.