Thin-walled containers that allow light to penetrate are less desirable than thicker walled pots, as light inhibits root growth. White pots are not desirable for this same reason. Mixes with adequate pore space for good aeration and good moisture retention work best. It is important that whatever medium is used, it is free of insects or diseases. No single commercial fertilizer is available to fill every poinsettia growth requirement.
Most growers use a rotation of fertilizers to complement key growth stages.
All essential elements must be supplied in appropriate rates and balances for optimum growth. Approximately 2 weeks from sale drop all fertilizer and irrigate with clear water unless plants show symptoms of yellowing or other nutrient deficiencies. For more information, see Technical Information Bulletin on Fertilization. Height control may involve preventing internode stretch that causes plants to get too tall, or promoting stem elongation that allows plants to reach their desired height. The challenge is to understand when the appropriate action is required.