Answer: Sudden yellowing and drooping can indicate dessication (drying) due to hot, windy conditions, or it could be a symptom of overly wet soil. To check soil moisture, dig down near the roots of the plant. If soil is damp 3-4" below the surface, you won't need to water (regardless of the temperature). If it's dry or barely moist, it's time to water. Roots in poorly draining soils can suffocate because water drives out air and air is essential to good root development.
The nice thing about banana plants is that they can die down to soil level (usually because of a cold snap) and then begin to grow a brand-new main stem the following spring. So, if the worst happens and the top of your plant dies down, give it a few months to recover and it will probably send up a new sprout.
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