Benchrunner Relay: Cold Growing Poinsettias

Benchrunner Relay: Cold Growing Poinsettias

If managed properly through variety selection and scheduling, Paul Ecke III says cold growing poinsettias makes total sense. He wrote us in response to an article in the July issue of Greenhouse Grower that stated cold growing at 61°F, based on research conducted for the article, wasn’t recommended.

Here is an excerpt of the letter Ecke wrote:


In the summary of the article, Dr. Lopez states cold poinsettia production at average day temperatures as low as 61° F is not recommended because of delayed flowering, a reduction in bract size and plant height, all impacting marketability of the finished product. While we agree there are risks to growing cold, if managed properly through variety selection and scheduling, cold growing does produce commercial quality plants with large bracts that size up to specification and are ready for peak season sales.

To help clarify, we are working with Dr. Lopez on this project and have more studies planned in 2008-09. What was not made clear in the article was that the trial was started late and results are based on growing conditions colder and darker than a poinsettia crop would normally experience. Trials in 2008 will be started earlier to come closer to a commercial schedule. Dr. Lopez shares with us a strong belief that cold growing is a feasible and reasonable practice to help growers manage production costs and stay competitive.

Growers in Europe already use cold growing extensively. Testing to support this program has been conducted over multiple years at several of the top research stations in Germany–and our genetics have been included. We have been carefully tracking results.

In North America, we are working proactively with researchers like Jim Faust from Clemson University and with commercial growers around the country to better understand how to grow poinsettias cold, not just how to finish them cold.  Dr. Lopez’s article presents some interesting data, but unfortunately due to the late start, data is not very practicable for growers. He achieved 61°F ADT (65/57°F (day/night)) at the start of short days. Such a low temperature is not likely to occur naturally in September when floral initiation normally occurs. Our trials have yielded reduced energy costs averaging 21 percent, a significant move toward cost control and sustainability. 

Success with cold growing is achievable with proper variety selection. We agree fully with Dr. Lopez that not every variety is adaptable to this regime. It also requires adjustments to production schedules and attention to height tracking to assure plants meet height specifications. To assist growers with cold growing, Ecke Ranch hosted two Webinars during July to discuss the program and answer questions from growers preparing for the upcoming season. Information, including a tool to help growers manage timing through temperature based on stage of development called the ‘Bract Meter’ is available at

Paul Ecke III
Chief Executive Officer
Paul Ecke Ranch