What this "poinsettia in a can" actually is is a grow your own poinsettia kit. Why anyone wants to grow a poinsettia from seeds is beyond me, but I guess I shouldn't be too judgmental. I shop at dollar stores, and I bought a poinsettia in a can. So who am I too look down on the poinsettia buying habits of anyone.
You get a can's full of vermiculite and about ten seed of Euphorbia pulcherrima to grow. E. pulcherrima is native to Mexico and is the common red poinsettia you see everywhere around the holidays.
Growing Poinsettia from SeedI shouldn't be surprised by the fact that the instructions and artwork on the can make it seem like you'll have a "flowering" poinsettia growing in a short time in this can. Poinsettias can grow between 2-6 feet tall, making them too big of a plant to grow in this little can. Poinsettia seeds are dark germinators, they should be covered with a thin layer of growing medium and kept moist until they germinate. Which should take between one and two weeks. If you're sowing poinsettia seeds in December to have a "flowering" plant by Christmas, it isn't going to happen. You can get your seed grown poinsettia to "bloom" by next Christmas though.
Getting a Poinsettia to FlowerHow do you get a poinsettia to bloom? Most people who buy poinsettias, and probably those trying to grow them from seeds, don't realize that the "flower" we associate with poinsettias are actually bracts. In botany, bracts are modified leaves that are associated with the reproductive parts of a plant's flower. Actual poinsettia flowers are small and pretty insignificant. The colored, most often red, parts of poinsettias that are thought of as flowers are leaves. These leaves turn the familiar red with changes in the day and night cycle. If you want a poinsettia to flower by Christmas, you'll need to start giving it 12 hours of total darkness every day in October. Keep the poinsettia at 68 to 72 degrees and either cover it with a box or set it in another room where no lights will be turned on for those 12 hours. When December rolls around you'll see the bracts start to turn the red you're looking for.
Wonder how they get poinsettias to be all compact and bushy? See the guest post The Pathogen in Your Poinsettias.
I've always thought that poinsettias where the SPAM of the gardening world. Seeing a poinsettia in a can just solidifies my belief.