Anytime, but like a banana, it will taste better when it is ripe and it won't give you a tummy ache. Have you tried them deep fried? Wow! Freeze the plantain first, then slice it and drop the frozen slices into a Fry Daddy or a small pan of hot oil. Stand back because it will splatter, but it is worth the risk. What you get is a great tasting snack that is even better with saviche or your favorite lime flavored dipping sauce.