(10/8/12) -- Regulating plant growth after flower induction is important because it gives the grower more control over timing and plant size for retail. Plants can easily become overgrown and/or grow too quickly before they're ready to ship. Growers should know which products and appropriate rates to use for different production stages. Use the tips below as a guide for plant growth regulator use on poinsettias.
Ultra low-rate Bonzi® plant growth regulator drenches: When plants are taller or growing faster than desired and Cycocel® plant growth regulator spray applications are not providing adequate growth control, an early- to mid-season (late September through October), Bonzi drench at a low-rate provides additional growth control without delaying color, distorting bracts or significantly reducing the bract size. Recommended drench rates after flower initiation and prior to 50 percent color are 0.05 to 0.1 ppm. The 0.1 ppm rate is used on vigorous-growing varieties and when moderate growth control is desired.
The 0.05 ppm rate is used on medium-growing varieties or when the growth rate needs to be slowed down slightly. Keep the total accumulated amount (from several drenches) to a maximum of 0.25 ppm until plants are at least 50 percent colored to prevent delaying color and reducing bract size. It is critical that the drench volumes are consistent from pot to pot. A good starting volume is about 1 fl. oz./1 in. pot diameter.
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Growth Regulation of Poinsettias After Flower Induction
