A frequent question at the Extension offices every year as fall approaches is "When should I pick my pears?" Most people know that if you let pears ripen on the tree, they are likely to break down at the core and be soft and mushy when eaten or canned.
Commercial growers use a pressure tester to determine proper pear maturity for harvest. By determining the pressure necessary to puncture the flesh, they can determine when pears are ripe enough to pick, but not overripe. What do you do if you don't have such an instrument?
In most years we can determine within a week or two, when individual pear varieties should be getting close to proper maturity. The following chart should cover western Washington. Choose the earlier date for southwest Washington and the later date for more northerly or colder areas.
The next step in determining picking readiness is ease of fruit removal. If you notice several pears dropping from the tree, you may be too late, but it's a sure sign they should all be picked. Every few days as you approach the harvest period above, give the pears the "lift test." Putting your index finger on the stem, lift the pear from the normal vertical orientation to a horizontal or flat position, perhaps with a slight twist. If the fruit "snaps" off cleanly between the stem and the twig, the pears are ready to strip from the tree. If you have to wrench off the fruit either breaking the twig or the fruit stem, the fruit is probably not ready. On larger trees, fruit growing in the top often ripens earlier than fruit in the shaded interior.
Certain late ripening pear varieties (Anjou, Bosc and Comice) may not ripen properly if just picked off the tree and allowed to ripen naturally. These varieties, particularly Anjou, need 3-4 weeks of storage at 32° - 45° F. This can be done in the refrigerator or possibly in a root cellar. Some kind of wrapping to reduce shriveling is a good idea.
How about Asian Pears? These are easy to pick since they ripen on the tree. Simply sample them from time to time as they ripen from greenish to various shades of yellow or orange. When they taste good, pick them. You don't have to pick them all at once, but if they are left on the tree too long, they may develop a "winey" taste that you may not like.
For more information contact your local WSU Extension Office.