%0 Journal Article
%T Timing of a Short-Term Reduction in Temperature and Irradiance Affects Growth and Flowering of Four Annual Bedding Plants
%A James E. Altland
%A Jennifer K. Boldt
%J Horticulturae | An Open Access Journal from MDPI
%D 2019
%R https://doi.org/10.3390/horticulturae5010015
%X Heating and supplemental lighting are often provided during spring greenhouse production of 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 days when the low-energy exposure occurred before flowering. Flower number was reduced 40每61% in impatiens, 33每35% in petunia (low-energy weeks 5每6 and weeks 7每8, respectively), and 35% in pansy (weeks 5每6). Petunia and impatiens dry mass gradually decreased as the low-energy exposure occurred later in production; petunias were 26% (weeks 5每6) and 33% (weeks 7每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. View Full-Tex
%U https://www.mdpi.com/2311-7524/5/1/15