No Spike - No Bloom Lady Slippers

[Gunde]

I am new to the forum. Your help will be VERY APPRECIATED!

I live in Las Vegas and over the years have purchased many orchids from Trader Joe’s Market. The orchids are kept in a 78 degree F room during most of the year. Most shot up a spike and bloomed without the twenty-degree night-day temperature differential that is supposed to be required to trigger a new spike. After the blooms were finished, I cut the “spikes”. All have been fed following the directions on the orchid food bottle. All bloomed again the next year EXCEPT the lady slipper orchids. We had a real spring in Las Vegas this year, so I put the slippers outside for several weeks to no avail. Still no spikes and no blooms. What am I doing wrong?