Phalaenopsis "Gone Crazy": Healthy Growth But No Flowers for Years

Jane (UK) has a 5-6 year old Phalaenopsis with 6 healthy leaves, a flower spike with 7 light-green nodules that refuses to develop, healthy aerial roots, proper watering (by pot weight), occasional misting, 16-23°C temps, indirect light from overhead window, humidity trays, and biweekly spring feeding. Other orchids (Paphiopedilum, Cattleya, other Phals) thrive.

Three Likely Issues

1. Temperature: 16°C (61°F) minimum may be too warm. A brief chill to ~13°C (55°F) for a couple weeks often triggers spiking.
2. Fertilizer formulation: High nitrogen (first number) promotes leaves, not flowers. Switch to a "bloom booster" with high middle number (e.g., 10-30-10).
3. Light level: Leaves should be light green, not dark green. Increase light slightly to stimulate pigment and flowering.

Outlook

This plant has enormous stored energy. Correcting these factors should produce a spectacular bloom.