Why is my banana plant not producing fruit?

Banana takes 9–12 months from planting to fruiting. If it has been that long with no flower spike: the pot is too small (use 25+ litres for Dwarf Cavendish); potassium is deficient (banana needs heavy potassium feeding — apply 0:0:50 monthly); the plant has too many suckers competing for energy (keep only one sucker); or it is a non-fruiting ornamental variety. Full sun (8+ hours) is mandatory — shade delays flowering significantly.