Poinsettias are among the most popular holiday plants, but they’re often treated as a “throw-away” plant. Unfortunately, as soon as the New Year arrives, most of them make their way to the garbage dump or compost pile. Rather than disposing of these lovely plants, they should be grown as a house-and-garden plant all year long. Even when not in flower, poinsettia’s dark green, tropical foliage is quite striking.
After the holidays pass, continue to keep your poinsettia in a bright window, but out of direct sunlight. With proper care, it will stay in flower for many weeks. Place your poinsettia in a room with a daytime temperature between 65 and 75 degrees F. Nights can be a bit cooler, but the temperature shouldn’t dip beneath 55. Be sure to keep you poinsettia away from cold drafts. These tropical plants resent cold temperatures. Also avoid hot drafts, such as those from appliances and forced-air heating ducts.
Water the poinsettia whenever the soil is dry to the touch. Do not allow it to completely dry out. To water, put the pot in the sink and flush tepid tap water through the pot until the potting soil is saturated. Allow the container to fully drain before putting the plant back on display.
Some of the leaves and bracts (the colored “leaves”) may drop off over the coming weeks. This is normal. While the plant is still in bloom, fertilize every three weeks with an organic, water-soluble liquid fertilizer. Allow the plant to continue to grow until all the bracts naturally drop in late winter. As soon as all the bracts drop, discontinue fertilization and reduce watering to once every 10 to 14 days.
From now until spring, the plant will be resting; perhaps entering a completely dormant state if all of the leaves drop off. As long as the stems remain flexible the plant is still alive. In early March, cut the plant back by a third. By removing the terminal portion of all the stems, branching is encouraged and the plant will stay compact and well-shaped.
In late April, begin to put the plant outdoors in a shady site only for a few hours during the day, and only if temperatures remain in the 50s or 60s. Bring it back indoors at night. The plant will slowly become acclimated to outdoor growing conditions and will begin to produce new leaves. Once the danger of frost has passed, repot the plant into a slightly larger container using new potting soil or plant it directly into the ground. Position it in full to partial shade. Keep it out of direct sun during the mid day.
Continue to water your poinsettia throughout the summer months and fertilize every two weeks with an organic, water-soluble fertilizer. In early July, prune the plant again, removing about a third of the plant’s height. This encourages further branching.
Once early September arrives, move the plant back indoors. You must do this before the nighttime temperatures drop below 50 degrees F. Starting Oct. 1, get the plant to re-bloom by keeping it in complete darkness for 14 hours each day. This period of darkness cannot be interrupted by any amount of light, natural or artificial. Many people put the plant into a dark closet until the 14 hours have passed. Doing so means that every day at 5 p.m. the plant goes into the closet, and every morning at 7 am it comes out, religiously and without fail. Poinsettias are so sensitive that if you miss a night or the room is not completely dark, the plant might not turn colors at all. You can also put the plant into a large, black plastic trash bag sealed with a twist tie for 14 hours each day.
Once the poinsettia begins to show color, about eight weeks later, you can discontinue the process and enjoy your beautiful blooms for another holiday season.