Sorry, I can not type chinese now $ g6 t/ U _. V5 X3 k 5 ?( p8 W2 G# M6 P6 c% S8 wBut, I put the poinsettia in a seperate room which should have more than 10hrs black time. Maybe it need more sun light?
at least 10hrs darkness, you can treat it 10~14hrs or longer ,it does not a matter, just a couple of hrs of sun light. and hopefully it can change corlor 3 weeks later till x-mas day.