I need advice about length of time my phals need the 10-15 degree temperature drop at night to induce blooming. I bought a small window A/C unit ($119 at Lowes) for my orchid room because here in Florida without it I can't give them that differential. According to the AOS culture sheet they need it for several weeks in the fall. But how long is that? If I have to use the A/C year round I will but if I only need to have it on say August through September it would help with the electric bill.