Chances are, you know the ABC's of growing poinsettias by heart after growing them for years. . . But what about your employees? Circulate this newsletter to new employees in need of some basic poinsettia training.
Ideally, do not leave poinsettias in their sleeves for more than 24 hours. Sleeving for a long period may cause epinasty. If leaves remain bent upward for too long, the plant will produce ethylene, which causes droopy leaves and bracts.
Some fruits (apples, bananas for example) produce ethylene. Poinsettias should never be transported, store or displayed near these fruits. (When did you last visit your super market flower/plants section?) Ethylene production increases as temperature rises: higher temperatures during transport lead to higher ethylene levels, hence more severe epinasty. Not all cultivars are equally sensitive to ethylene. Newer cultivars tend to be much more resistant to this condition.
The best temperature range for transporting poinsettias from the greenhouse to the store is 50-55º. Below 50 º, chilling damage may occur. Plants can recover from this condition in 48 hrs. unless they have been sleeved for to long. Remember to teach your new employees to remove sleeves gently in order to avoid damage and bruises.
Low post-production quality can be manifested as a premature leaf drop and it may be associated with high growing mix EC (high salts) due to over fertilization in late production. To avoid this problem it is advisable to keep low growing mix EC in late production. It is often recommended to stop fertilizing the last two weeks of the crop. However, according to Dr. Bill Argo, that recommendation doesn't take into account how the crop has been managed up to that point. Poinsettias still need some nutrition during those last two weeks. He suggests that if you use low to moderate nutrient levels during production, you may want to continue applying some fertilizer for the last two weeks of the crop. If you use flood irrigation, do not stop fertilizing. With subirrigation, nutrients move rapidly from the root-zone to the medium surface. A single irrigation can remove almost all of the nutrients from the root-zone.
