To maximize the color process, it is best to keep the plants in bright but indirect sunlight in the day (6 hour min) with complete darkness at night (out of street lights, landscape lights and other forms of man made lights). Complete darkness is required for optimal color, as poinsettias are photoperiodic.
The poinsettia should be watered frequently, but only when the soil no longer FEELS moist or lightens in color. DO NOT allow the soil to dry out. Avoid over watering as well as poinsettias should not sit in water. It is best to water poinsettias with the pot covers removed and allow the water to drain before replacing the cover or pot. If you do water with covers make sure to empty any water from a pot cover, pot or basket that may hold your poinsettia.
It is best to keep your poinsettia away from drafts, fluctuating temperatures, excess heat and ventilation ducts. Poinsettias enjoy areas of medium to high humidity as opposed to dry air. Temperatures less than 50 degrees Fahrenheit can be detrimental to the life of your poinsettia, as they are very sensitive to the cold. If you see the leaves are wilting after a cold snap leave it alone. Many people make the incorrect assumption it needs to be watered and then over water their plant. The best way to see if your poinsettia needs to be watered is to stick your finger in the soil a few inches.
Poinsettias can be kept as beautiful foliage plants once the holidays have passed. To ensure the continued health of your poinsettia, fertilization will be required. Cut the branches of the poinsettia back in May, about 6 inches. Pinch by mid-August and allow no night time light after Oct 1.
Contrary to popular belief, poinsettias are not poisonous, but like most ornamental plants they should not be eaten. Keep poinsettias away from children and animals.