Fall is here in San Jose
Arnold Trachtenberg (Sun, 21 Sep 2008 18:15:18 PDT)

Bloom initiation has been discussed here at length. You may try
searching the archives.

I think there are many factors that cause a flower to bloom.

I have Arums in a basement under HID lights that know when fall is
approaching in spite of the fact that I never change the day length on
the artificial illumination. The temperature is relatively constant as
well.

Arnold