Watering
Water when the top 50% of the soil is dry. Watering too often to create soggy soil leads to root rot, but letting your poinsettia get bone dry can cause the roots to dry back. Water thoroughly until it flows out of the drainage hole and discard any excess water.
Lighting
Your poinsettia prefers indirect, but bright light. Too much light will cause the foliage to get crispy and brown, but too little light will cause yellow leaves. An eastern window is perfect for this plant, or a little further back from a southern or western window works as well.
Temperature
These tropical plants like consistent warm temperatures. Be sure to keep your poinsettia away from any drafty areas or open vents. A sudden change in temperate will cause your plant to go into shock.
Improper Fertilization
Plant fertilizer can give your potted plants a boost, but only when used properly. If you over-fertilize or apply incorrectly, you can burn your plant’s roots. Fertilize after the plant begins growing again in the spring, and then once a month during the growing season. No fertilizer is needed during the winter months. Never apply fertilizer to dry soil.