To keep a cut avocado fresh, whether it's ripe or not, sprinkle lemon or lime juice on the exposed flesh. This helps prevent the inside from turning brown. Wrap it in plastic wrap or place it in an airtight container and store it in the refrigerator up to four days.
If you have an avocado that is unripe and uncut, you can keep it fresh by storing it at room temperature between 65 and 75 degrees Fahrenheit for four to five days until it ripens.
Avocados are fruits that grow in warmer areas of the world, such as California, Mexico and parts of Central America.