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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9.2 Determination of flowering The flowering time of the earliest 5°C tulips depends amongst others on when the cultivar in question reaches stage G. After reaching this stage, most cultivars are given an intermediate temperature treatment, al-though for other cultivars the cold treatment starts immediately after reaching stage G. By adding up the time required in the greenhouse, the time of harvest can be calculated. The start of the cold period given to batches not intended for early, but for late flowering, is not determined by the completion of stage G, but by simply counting back from the required flowering time. For example: the required flowering period is 8 March; by counting back 50 days, this gives a planting date of 18 January, minus 12 cold weeks gives 24 October as the desired start of the cold phase.