In a reversal of overwintering flowers, I over-summered this poinsettia. Basically, I treated it like any other container plant during the summer, watering and some fertilizer. In the fall, I moved it into the sunroom. I avoided letting it get any artificial light, just what the sun provided. It rebloomed nicely, nice and red.
This is my first try at reblooming a Poinsettia. Here are my observations.
1. The original soil might be fine for greenhouse growth and transport, but has really lousy water retention and once dry, can't be re-wetted easily. Once I repotted the plant into a "normal" potting soil, removing most of the old peat. It did much better and was much easier to keep watered after repotting.
2. The stems are quite brittle and break easily. They need support or protection.
3. The flower was smaller than for the purchased plant. I still like it anyway, very pretty.
We'll see if I can keep it another year. I'd like to prune it back a bit to make it bushier.
Meanwhile, I bought a new one at Winco.
We'll see how that over-summers too. It's kind of fun doing that.