Use of Growth Retardant on Classic Zinnia (Zinnia angustifolia Kunth) to Make Commercial Pot Plant

Abstract

This study was conducted to improve the potential of Zinnia angustifolia Kunth as pot plant. Paclobutrazol was used to make plants more impact and decrease its size to fit the 4-inch pot. It was effective in regulating the plant height and size. The change of growth retardant concentration while the plant was growing up increased their effectiveness in regulating the plant height, size and other aesthetic characteristics related to pot size. Using paclobutrazol at 10 ppm on 21-day-old plant 4 times and changing to 25 ppm 3 times gave the best result for Zinnia angustifolia Kunth grown in July-September (rainy season). The plant size fitted the pot best without reducing the flower size and number. However, This application was not suitable for those grown in October-January (winter) for it reduced the plant size and flower number. The best application for winter was using paclobutrazol at 10 ppm on 21-day-old plant 4 times.