If you can purchase a few rooted cuttings, you will enjoy growing both red and white poinsettias to flower at Christmas. Pot rooted cuttings in 2 1/2- or 3-inch pots in soil mix of three parts garden loam, one part clean sharp sand, and one part well-rotted manure. Water thoroughly; place in shade out of direct sunlight until they become established; mist or syringe lightly several times a day. Pinching to induce branching will produce more than one blossom per plant.
A hard pinch (removing entire top of plant including several leaves) should be made no later than August first; a soft pinch (removing tip only) can be made August 15. When plants outgrow small pots, repot singly, or several to a 6- or 8-inch pot. Water thoroughly after repotting. Maintain temperature at 60 F, avoid drafts, and water moderately. Too much or too little water, sudden changes in temperature, or drafts cause foliage to drop. Color should be evident by November fifteenth. Apply a complete fertilizer every two to three weeks after color appears, and full color should be attained by Christmas. Poinsettias set buds between October tenth and twentieth take care not to expose plants to artificial light during these ten days; otherwise, you may have no flowers.
After flowering, plants may be carried on as stock plants to furnish cuttings for the next season. Place pots on sides in a 50 to 55 F temperature until April; cut back to 8 inches and repot. Raise temperature to 60 or 65 F and syringe and water frequently. One ounce of ammonium sulfate dissolved in two gallons of water helps at this time. Anytime May to August make 4- to 6-inch cuttings, preferably in the morning. Place them in water for an hour to retard loss of milky juice, then pot directly in 2 1/2- or 3-inch pots, or root in sand first. Water thoroughly to firm soil around cutting. Place shade some distance above cuttings to allow free air circulation, and syringe or mist several times a clay for about ten days.