Response of poinsettias to dynamic temperature integration with pre-morning and early morning temperature drop and root zone heating.

Hao, X.M., Zheng, J.M., and Little, C. (2015). "Response of poinsettias to dynamic temperature integration with pre-morning and early morning temperature drop and root zone heating.", Acta Horticulturae (ISHS), 1104, pp. 177-183. doi : 10.17660/ActaHortic.2015.1104.27  Access to full text

Abstract

Temperature control is one of the most important factors in greenhouse ornamental cultivation since it not only affects plant growth, quality, and the time of production cycle but also heating costs. Root-zone heating can reduce energy use in potted plant production but high root temperatures may be detrimental to roots. Since the highest heating energy use usually occurs during pre-morning or early morning periods, temperature drops during these periods could reduce energy use. In this study, two greenhouse experiments were conducted to investigate the response of poinsettias to dynamic temperature integration with pre-morning and early morning temperature drop and various root-zone temperatures to conserve energy while maintaining plant growth and quality. Two temperature integration (TI) regimes NDASH Control TI (17°C from 6 to 9 am, no temperature drop) and New TI with temperature drop (13°C from 6 to 9 am), were applied in 4 greenhouses (2 replications for each TI regime). Three root-zone temperatures (20, 24 and 28°C) were delivered inside each greenhouse. New TI improved or maintained plant growth and quality and also showed good potential for energy savings. Therefore, New TI, with proper pre-morning and early morning temperature drop, can save energy and maintain plant quality. High root-zone temperature reduced root growth at Control TI but not at New TI. Therefore, a higher root heating temperature may be used together with New TI for more energy saving.

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