Here are few tips to maximize the blooming period of your poinsettia and keep it healthy after the holiday season.
How to care for a poinsettia in bloom
Light
Place your poinsettia in a well-lit room, with as much indirect sunlight as possible.
Temperature
Keep the poinsettia at normal room temperature, but ideally not above 20°C. Nighttime temperatures of 16 to 17°C are best. Too much heat will shorten the blooming period.
The poinsettia is sensitive to extreme temperatures (below 10°C and above 30°C). Keep it away from heat sources like radiators and heaters. Also, avoid cold drafts and protect it during transport.
Watering
Water with water at room temperature when the soil feels dry to the touch. Moisten the soil thoroughly until the excess water drains out through the holes in the bottom of the pot, but never leave water in the saucer.
Between waterings, allow the soil surface to dry out. Avoid over-watering, which will cause the roots to rot, but don’t wait until the poinsettia is suffering from a lack of water before watering it either.
Fertilizing
Fertilization is not needed while the poinsettia is in the bract coloration stage.
Care After “Blooming”: The Vegetative Period
Depending on the cultivar, a poinsettia may remain in bloom for four months. After that time, its bracts will gradually lose their color.
The poinsettia is often replaced each year. However, if you wish to keep it as a green plant or attempt to make it bloom again, here’s how to care for it during the vegetative growth period.
Pruning and repotting
In late April, prune your poinsettia, cutting all the stems back by one third. For a more compact plant, keep only two or three leaves on each stem. Be sure to mist the plant with water to limit the seepage of latex and prevent it from drying out.
Poinsettias do not like to have " wet feet ". Repot the plant in an aerated, well-drained medium. You can use a ready-mixed commercial substrate or blend your own, using equal parts potting soil, perlite and peat moss.
Prune the plant again in late July or early August, or pinch back the ends of the stems (leaving three or four leaves per stem) to encourage bushy, compact growth. Never pinch a plant back after early September if you want it to rebloom.
Light
Give your poinsettia as much light as possible, even full sun. If possible, place it outdoors during the summer in a partially shaded or sunny spot, acclimating it gradually.
Wait for night-time temperatures to stay above 13°C before taking it outside. Bring it back indoors in September.
Temperature
After pruning, a temperature of 20°C is ideal. During the growing period after that, indoor temperatures from 20°C to 24°C are adequate.
Watering
After pruning, the poinsettia will require less water. Give it only enough to prevent the soil from drying out completely. Once growth resumes, water as necessary, allowing the soil surface to dry out between waterings. Outside, especially in full sun, be sure not to let it wilt!
Fertilizing
After the bracts show color (from late April to mid-September), use a soluble all-purpose fertilizer (N-P-K ratio: 1-1-1)* mixed with the watering water once a month. When new leaves appear, fertilize every two weeks to promote vigorous growth.
*Note: A fertilizer with a lower phosphorus content and an N-P-K ratio of 3-1-4 or 2-1-2 is ideal. As this type of fertilizer can be hard to find, a balanced soluble fertilizer (such as 20-20-20) can be used. Natural fertilizers can also be used. In all cases, follow the manufacturer's recommendations.