Place the avocados you wish to stop from ripening loose in the refrigerator. However, if your refrigerator has a tendency to freeze in some parts, such as against the back or sides, do not place the avocados in these sections. Refrigerate your avocados for up to five days. The ripening process will be very slow during this period, and the avocados you remove from the refrigerator should look very similar to the ones you put in days before. Remove your avocados from the refrigerator three to five days before you are ready to use or serve them.