Keep the plant short and compact by pinching out the tips of all new shoots that develop until the middle of August. Water the plant with a solution containing one teaspoon of soluble fertilizer per one gallon of water every two weeks throughout the summer. Since poinsettias are very sensitive to cold, bring the potted poinsettias into the house well before the first frost. Start new plants during the summer by allowing the shoots to become three to five inches long and then remove them. Root them in a pot of sterilized sand.
Poinsettias are plants that show a photoperiodic response.
In this case, these plants demand at least 12 hours of absolute darkness each evening to bloom. It is important that the cover be light-tight. Only 5 minutes of light an evening from a 60-watt bulb will delay flowering by two weeks. Continue to water and fertilize during this period. In the more northern climes where darkness reaches the 12 hour period in late fall, the use of shade cloth or other shading devices may not be necessary unless other light sources are present that will prevent flower bud formation.