Heat delay of poinsettia flowering is of growing concern across the U.S. as climate change has caused fall weather patterns to be less predictable and many regions of the country are experiencing higher average temperatures. A few extra degrees of heat at the wrong time can easily cause a one to two week delay in flowering, which can be disastrous for growers. Our research has focused on improving our understanding of the timing and magnitude of the high temperatures that cause heat delay and developing practical solutions to help growers avoid missing target market dates. Our results reveal that poinsettias are not equally susceptible to high temperatures throughout the fall. There are specific weeks of the poinsettia season that high temperatures will cause the largest delays in flowering. We have also identified the specific temperatures during the day and night that are most critical to avoid. By increasing our understanding of the variables that contribute to heat delay, we have identified practical solutions to avoid missing target market dates, such as cultivar selection and black-clothing. These solutions are discussed so that growers have practical options for addressing this phenomenon.

Speaker: Dean Kopsell, University of Florida Melissa Munoz, Clemson University

Growers seek to optimize plant growth while maintaining production costs. Interest in LED lighting has surged in recent years due to the potential energy savings. Growers continue to wonder if supplemental lighting with LEDs is needed for their greenhouse operations. Jim explains how to determine if your location and crops justify adding supplemental lighting.

Questions abound when considering the use of LED lighting. Choices of fixtures and light quality can be very confusing. Erik Runkle has been evaluating LED lighting since they were first available to the greenhouse industry. He simplifies the selection and use of LEDs, both indoors and in greenhouses.

Growing media seems to change constantly as growers seek a medium to grow plants successfully at the least costs. There have been major changes in growing media in the last 10 – 15 years. Topics include: What is important in a good growing media? Are there new components that growers should consider and are the components sustainable? What should growers be asking their supplier when selecting a high-quality growing media?