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Timing of a Short-Term Reduction in Temperature and Irradiance Affects Growth and Flowering of Four Annual Bedding Plants

Author:
Boldt, Jennifer, Altland, James
Source:
Horticulturae 2019 v.5 no.1 pp. 15
ISSN:
2311-7524
Subject:
Antirrhinum majus, Impatiens walleriana, Petunia hybrida, Viola, annuals, bedding plants, energy, energy conservation, flowering, flowers, greenhouse production, heat, light intensity, lighting, spring, temperature
Abstract:
Heating and supplemental lighting are often provided during greenhouse production of spring bedding plants, but energy inputs are a major production cost. Different energy-savings strategies can be utilized, but effects on plant growth and flowering must be considered. We evaluated the impact and timing of a two-week low-energy (reduced temperature and irradiance) interval on flowering and growth of impatiens (Impatiens walleriana Hook.f. ‘Accent Orange’), pansy (Viola ×wittrockiana Gams. ‘Delta Premium Blue Blotch’), petunia (Petunia ×hybrida Hort. Vilm.-Andr. ‘Dreams Pink’), and snapdragon (Antirrhinum majus L. ‘Montego Violet’). Flowering was delayed 7 to 10 d when the low-energy exposure occurred prior to flowering. Flower number was reduced 40%-61% in impatiens, 33%-35% in petunia (low-energy weeks 5-6 and weeks 7-8, respectively), and 35% in pansy (weeks 5-6). Petunia and impatiens dry mass gradually decreased as the low-energy exposure occurred later in production; petunias were 26% (weeks 5-6) and 33% (weeks 7-8) smaller, and impatiens were 20% to 31% smaller than ambient plants. Estimated energy savings were 14% to 16% for the eight week period, but only up to 7% from transplant to flowering. Growers can consider including a two-week reduction in temperature and irradiance to reduce energy, provided an additional week of production is scheduled.
Agid:
6472484
Handle:
10113/6472484