ISHS Acta Horticulturae 51: Symposium on Protected Cultivation of Flowers and Vegetables
SUPPLEMENTARY LIGHTING FOR SPRAY CHRYSANTHEMUMS |
| Author: | A.E. Canham |
| Abstract:
Poor winter light conditions during the first two weeks of the short-day period delay both flower initiation and flowering of pot and spray varieties of year-round chrysanthemums. During long days it reduces the rate of vegetative growth and increases the number of long days required for an adequate length of stem. In both cases the length of time the plants occupy the greenhouse is increased, resulting in increased production costs. The use of high-intensity supplementary artificial light has been shown to mitigate these effects in the case of plants grown in pots. In this paper the results of treatments given during both the long-day and short-day periods on spray varieties are presented. Lighting during the long-day period increased the rate of vegetative growth and the length of stem, but did not promote flowering. The results suggested that the length of the long-day period could be reduced from four to two weeks with the cv. 'Yellow Polaris' provided supplementary light was given for at least one of the two weeks. When supplementary light was given during the first two weeks of short days the plants flowered up to thirteen days earlier. | |
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