These plants absolutely need annual repotting to do well, and I usually do it in the fall (September). As far as blooming is concerned, the best quality blooms are the early ones since they open in cooler temperatures and hold bloom longer. The bulk of the blooms are in a bit warmer temperatures and the bloom quality suffers as a result. My best blooms are with 55-75F temperature spreads, and some do fine with 60F nights. The important factor is to limit the daytime heat.