Papayas will become sweet and juicy at home if they have not been picked too green. Papayas are one of the few fruits that will ripen after they have been picked. Papayas are not ripe if they are hard and green. Unripe papayas can be left at room temperature where they will ripen in 2—3 days. Don't refrigerate papayas until they are ripe; they will not ripen in the refrigerator. Place papayas on a flat surface with space between the fruit. It is best to turn them occasionally so that they will ripen evenly. Once their skin turns yellow-orange and they yield to gentle pressure, they are ripe and ready to eat. If you will not be consuming them immediately after they have ripened, place them in the refrigerator.
Another natural way to ripen papayas is to place them in a paper bag for 2 to 3 days. The paper bag traps the ethylene gas produced by the papayas. The ethylene gas helps them to ripen more quickly, while the paper bag allows for healthy oxygen exchange through the bag. Keep the paper bag in a dark, cool place as excessive heat will cause the papayas to rot rather than ripen. Turn papayas occasionally. Adding a banana, apple or avocado to the bag will speed up the ripening because they increase the amount of ethylene gas in the bag.