Cease watering your poinsettia plant once the leaves have dropped. Move it to a cool location where it receives indirect light. Maintain temperatures between 50 and 55 degrees until spring.
Cut the plant back to 3 to 8 inches above the soil in the spring when new growth appears. Cutting back is not necessary, but will produce a dense, compact plant.
Repot the poinsettia in a plant pot one to two sizes larger than the original. The University of Rhode Island horticulture program recommends a mixture of three parts potting soil, two parts compost or peat moss, and one part perlite for a potting medium. Add 1 1/2 to 2 teaspoons of bone meal per quart of potting medium.
Move the poinsettia plant to bright light. Water when the soil feels dry to the touch 1 inch below the surface of the soil.
Apply water-soluble fertilizer designed for houseplants following the recommended application rate. Repeat on a seven- to 10-day cycle.
Pinch back when the first clusters of leaves are approximately 1 inch long. Pinch out the center leaves, allowing 4 to 5 leaves per cluster to grow. This forces branching and produces new clusters of leaves at the end of each branch. Repeat again when the new clusters have formed leaves 1 inch long.