Nutrient potassium is critical in plantain (Musa species cv. AAB) nutrition. It plays a key role in the vegetative growth and bunch development. Application of 300 kg muriate of potash (K20) per hectare was beneficial in the plant crop, while a higher rate (400 kg K20/ha) enhanced growth and favorable yield components (number of hands and fingers/bunch, finger mass, girth and length). Plants fertilized with 400 kg K20/ha were tallest (3.5m), had largest pseudostem girth (56-58cm) with highest (11-12) number of functional leaves at flowering and attained flowering stage after 9 mouths of vegetative growth. Bunch mass, bunch yield/ha and yield components were significantly (P = 0.05) highest at 300 kg k20/ha in plant crop and at 400 kg K20/ha in ratoon crop. Heaviest bunches were 8.8 and 9.8 kg/plant in plant and ratoon crops, respectively, giving the respective corresponding bunch yields of 14.66 and 16.33 tonnes/ha. Application of 400 kg K20/ha appeared adequate for sustainable production of false horn plantain in the high rainforest zone of Cross River State.