Lily bulbs that are grown in a greenhouse are very useful for propagation. This is one of the conclusions from research by the Greenhouse Horticulture Business Unit of Wageningen University & Research. However, the correct lighting must be chosen to ensure that as much energy as possible is put into the bulbs.
Lily growers usually produce their own propagation material. They use the scales of large bulbs for this: a new bulb grows on them. An efficient method, but also a risky one. Diseases and pests remain in this way. Therefore, it is difficult for lily growers to grow lilies without the use of crop protection agents.
WUR is looking for a solution for the rapid propagation of healthy lilies. For this, scales are produced from tissue culture in a greenhouse. The resulting planting material is also grown in the greenhouse. In the last year, the bulbs are cultivated in the open field. The reason for this is that otherwise a grower would need too many greenhouses. With the new method, the production process is considerably shortened: approximately 3 years (instead of 4 or 5 years). In addition, fewer pesticides are needed.
The latest tests show that the bulbs that are grown in the greenhouse are very useful for propagation. It is important that the correct light spectrum is selected. Usually, the purpose of lighting is that a crop puts a lot of energy into growing a flower; with lily bulbs, the energy must go to the bulb. That therefore requires a different spectrum. Using the same light recipe that turned out favorably with potatoes (with a lot of far red) does not appear to be the solution.
Another point of attention is the last phase of the cultivation in the greenhouse, before the bulb is planted outside. This is because the lily crop does not die, as it does with outdoor cultivation. The consequence of this is that later growth abnormalities are possible, such as a flattened top of the bulb or a splayed bulb. WUR is investigating how this can be prevented.
The 'Vital lily cultivation' project is funded by the Ministry of Agriculture, Nature and Food Quality.