You may offer this plant lower temperature about 10-14 degrees C, but this is not necessary. Just colder windowsill will be good. The plant need a lot of light still.
Transplant your poinsettia to the same pot, but full with fresh soil. Transplanting to larger pot will cause plant's larger vegetative growth, but it harder will be to get coloured leaves at the top. Add fertilizer every 2 weeks.
As result, anyway, you will get the plant which will be larger from previous size and those available in the shop, because manufacturers use special repressing growth substances, so plant is more compact. If you want to make it also more compact, use this special technique of pruning, that will keep it more compact. On the beginning of July prune every new stem about 2 cm. In August, cut off all new growth about 1-2 cm.Poinsettia neeeds "short day" (10 hours of light a day) in order to grow coloured leaves. The night has to last at least 14 hours – even the tiny bit of light during dark hours will cause lack of colour.
One and a half month before appointed deadline, when you want to have coloured plant you may start to artificially darken the plant. You may close it in a wardrobe, cover with cardboard box. Choose the easiest way, because you will be doing this for 6 weeks.
If it don't do it, your poinsettia will get naturally color mid of January. Practically whole December and whole January day lasts shorter than 10 hours, so mid of January the leaflets will start to change color.
1. Keep her safe from cold air.
2. Draughts is killing the plant.
3. In sunny place.
4. Provide moist to the soil constantly. Manufacturers usually use very quickly drying up basis unfortunately, therefore it is difficult to keep th eplant moist all the tome. Ponsettia also can not be standing in water, soil should be only moist.
5. Do not cut flowers (these tiny yellow on top), because they are necessary to get coloured leaves.
6. In period of blooming add fertilizer every weeks.
What about you? Do you still have poinsettia around? Will you give it a chance?